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Reverse osmosis (RO) is affected by multiple types of fouling such as biofouling, scaling, and organic fouling. Therefore, a multi-functional membrane capable of reducing more than one type of fouling is a need of the hour. The polyacrylic acid and graphene oxide (PAA-GO) nanocomposite functionalization of the RO membrane has shown its effectiveness against both mineral scaling and biofouling. In this research, the polyacrylic acid concentration and irradiation times were optimized for the PAA-GO-coated RO membrane using the response surface methodology (RSM) approach. The effect of these parameters on pure water permeability and salt rejection was investigated. The models were developed through the design of the experiment (DoE), which were further validated through the analysis of variance (ANOVA). The optimum conditions were found to be: 11.41 mg·L−1 (acrylic acid concentration) and 28.08 min (UV activation times) with the predicted results of 2.12 LMH·bar−1 and 98.5% NaCl rejection. The optimized membrane was prepared as per the model conditions, which showed an increase in both pure water permeability and salt rejection as compared to the control. The improvement in membrane surface smoothness and hydrophilicity for the optimized membrane also helped to inhibit mineral scaling by 98%. [ABSTRACT FROM AUTHOR]

Air-conditioning systems make the most significant part of energy consumption in the residential sector. There is no denying that it is essential to produce a comfortable indoor thermal environment for residents in a building. The actual goal is to achieve thermal comfort level without putting too much cost on the ecological system by trying to conserve the amount of energy consumed. An effective way to help achieve such a goal is by incorporating thermal insulation in buildings. Thermal insulations help reduce thermal energy gained during the implementation of a desired thermal comfort level. This study aims to use an environmentally friendly nanoparticle of date pits to create thermal insulations that can be used in buildings. Different ratios of the nanoparticle of the date pits and sand composite were investigated. Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the new materials. The material with nanoparticles of date pits and 50% by-volume epoxy provided good thermal insulation with thermal conductivity of 0.26 W⁄mK that could be used in the existing buildings. This has the potential to reduce the overall energy consumption by 4,494 kWh and thereby reduce CO2 emissions of a 570 m2 house by 1.8 tons annually. In conclusion, the future of using nanoparticles of date pits in construction is bright and promising due to their promising results. [ABSTRACT FROM AUTHOR]

In this study, municipal solid waste bottom ash (MSW-BA) and fly ash (MSW-FA) were used as a source of aluminosilicate to prepare geopolymer (GEO) adsorbents (GEO-MSWBA and GEO-MSWFA) for the removal of methylene blue (MB) from water. The effects of temperature, pH, and initial concentration on the MB adsorption onto GEO-MSWBA and GEO-MSWFA were evaluated. The adsorption isotherms parameters and thermodynamics were also determined. Detailed physical and chemical characterizations of the prepared adsorbents were carried out to further understand their impact on MB adsorption. The results from the scanning electron microscopy revealed a uniform granule-sphere like structure on both prepared geopolymers, which would facilitate the MB adsorption onto the adsorbents. The X-ray diffraction allowed observation of the microstructural transformations that occur after the alkaline activation. The surface areas of the GEO-MSWBA and the GEO-MSWFA were recorded as 32.78 m2/g and 4.5 m2/g, respectively. From the Fourier transform infrared, a stretching vibration of the aluminosilicate tetrahedral was observed, which indicated the success of geopolymerization. The prepared geopolymers showed a high capability of MB adsorption from an aqueous solution. The adsorption process was best suited and explained using the Langmuir isotherm model with a maximum adsorption capacity of 666.7 mg/g for the GEO-MSWBA (at 25°C) and 769.2 mg/g for the GEO-MSWFA (at 35°C). The positive value of the enthalpy (ΔHo) for the GEO-MSWBA suggested the reaction favored endothermic reaction while the negative value of entropy (ΔSo) indicated a solid/liquid random interaction. On the other hand, the negative ΔHo value for the GEO-MSWFA indicated the reaction followed an exothermic reaction causing energy to be released, the positive ΔSo value indicated a good affinity at the solid-liquid surface. The overall negative value for Gibbs free energy (ΔGo) for both adsorbents suggested the adsorption was spontaneous and feasible. It was also inferred that n- π interaction, direct and indirect hydrogen bond, and electrostatic interaction between the MB and the prepared geopolymers facilitated the adsorption process. The current study shows that the GEO-MSWBA and the GEO-MSWFA have a great potential of removing MB as a cationic dye from water without performing any sort of laborious pretreatments. [ABSTRACT FROM AUTHOR]

Incineration has emerged as one of the acceptable ways to treat municipal solid waste (MSW) due to its potential in reducing the mass and volume of the waste. However, it produces two major by-product residues, namely MSW-bottom ash (MSW-BA) and MSW-fly ash (MSW-FA). These residues have gained great attention to their hazardous nature and potential to be reused and recycled. In this paper, the physicochemical characterizations of the MSW-BA and the MSW-FA were performed, followed by a systematic investigation of metals extraction from MSW-BA and MSW-FA. Various extracting agents were used to investigate the possibility to extract 21 metals including cadmium (Cd), vanadium (V), chromium (Cr), and lead (Pb). It was revealed that some metals were present in a high amount in the MSW-BA while other metals were higher in the MSW-FA. Moreover, the energy-dispersive X-ray spectroscopy results revealed that the MSW-BA was dominated by oxygen (O) 55.4 ±0.6 wt%, silicon (Si) 22.5 ±0.3 wt%, and calcium (Ca) 18.5 ±0.2 wt%. On the other hand, the MSW-FA was enriched with Ca 45.2 ±0.5 wt%, and O 40.3 ±0.4 wt%. From the scanning electron microscopy, the MSW-BA was observed as flaky with an irregular surface that consisted of large pores, while, the MSW-FA was present as agglomerated particles and had a bimodal distribution. Moreover, Fourier transform infrared spectroscopy revealed that Al-Fe-OH, Al-Al-OH, Si-O, C-O, and C-H were some of the major functional groups present in the ashes. The F-tests concluded that the metal extraction from the MSW-BA and MSW-FA were significantly affected by the acid type. it is concluded that nitric acid and phosphoric acid were the best-suited acid for the MSW-BA while sulfuric acid and phosphoric acid for the MSW-FA. More than 11 wt% of Cd and 9 wt% of Cu were extracted from MSW-BA while 6 wt% of Pb and 4.5 wt% of V were extracted from the MSW-FA. The present methodology is an interesting development in metal extraction from the MSW-BA and the MSW-FA, which can develop in a cost-effective and sustainable option to utilize MSW. [ABSTRACT FROM AUTHOR]

In this study, activated carbons prepared from the green and black olive stone (green OSAC and black OSAC) were used as adsorbents to investigate their removal efficiencies for oxidation products and polar compounds from used sunflower and corn cooking oils. The degree of oxidation level and polar compounds were evaluated using Fourier transform infrared (FTIR) with the principal component analysis and ultra-performance liquid chromatography. Two FTIR absorption peaks were used for the oil evaluation, namely 3007–3009 cm-1, which is related to C-H symmetric stretching vibration of the cis double bonds, and ~1743 cm-1, which is related to = CH and ester carbonyl stretching vibration of the functional groups of the triglycerides, C = O. The principal component analysis results showed significant variations in the oxidation level of the sunflower and the corn oils occurred after consecutive heating and French fries frying for 10 days. The oxidation products that are adsorbed on the surface of the OSAC forms π-complexes with the C = C parts of the OSAC system. It can be concluded that the prepared adsorbents can be promising, efficient, economically effective, and environmentally friendly alternative adsorbents for oil treatment applications. [ABSTRACT FROM AUTHOR]

Background: The use of agricultural waste as a low-cost adsorbent for the removal of hazardous methylene blue (MB) from aqueous solution was investigated. In this research, the potentiality of using black nano olive stones (black NOS) and green nano olive stones (green NOS) for MB adsorption was conducted. Methods: Various remediation parameters such as initial MB concentration, pH, and temperature were investigated. Thermodynamic study was carried out to determine the homogeneity of the adsorbent and spontaneity of the adsorption process. Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius and pore volume. Results: It was found that NOS exhibits an acidic nature, however the highest MB removal efficiency was recorded at pH 10; reaching up to 71%. The negative value of the heat of the adsorption process (∆H °) indicated the reaction followed an exothermic pathway while the negative value of Gibbs adsorption (∆G °) further suggested its spontaneous nature. The results indicated that the Freundlich model described well the adsorption process with 99.5% correlation coefficient for green NOS. FTIR was used to analyze functional groups on the adsorbents' surfaces that could play vital roles in the remediation process. SEM analysis revealed that the adsorbents comprised of abundant spherical deep cavities and porous nature. Conclusion: The result obtained successfully demonstrated the potential of using black and green NOS as suitable adsorbents for the removal of MB from water. [ABSTRACT FROM AUTHOR]

This study aims to prepare an ion-imprinted polymer (IIP) using copper sulfate as a template and potassium persulfate as an initiator to selectively adsorb copper ions (Cu2+) from aqueous solutions and in an attempt to also test its applicability for removing strontium ions (Sr2+). The prepared polymer was denoted by IIP-Cu. Various physical and chemical characterizations were performed for the prepared IIP-Cu. The scanning electron microscopy and transmission electron microscopy analyses confirmed the cavities formed after the removal of the template. It also indicated that the IIP-Cu had a rough and porous topology. The X-ray photoelectron spectroscopy confirmed the successful removal of the Cu template from IIP-Cu. The Brunauer-Emmet-Teller revealed that the surface area of IIP-Cu is as high as 152.3 m2/g while the pore radius is 8.51 nm. The effect of pH indicated that the maximum adsorption of Cu2+ was achieved at pH 8 with 98.7%. Isotherm studies revealed that the adsorption of Cu2+ was best explained using Langmuir models with a maximum adsorption capacity of 159 mg/g. The effect of temperature revealed that an increase in temperature had an adverse impact on Cu2+ removal from the aqueous solution, which was further confirmed by thermodynamic studies. The negative value of standard enthalpy change (−4.641 kJ/mol) revealed that the adsorption of Cu2+ onto IIP-Cu was exothermic. While the continuous increase in Gibbs free energy from −6776 kJ/mol to −8385 kJ/mol with the increase in temperature indicated that the adsorption process was spontaneous and feasible. Lastly, the positive value of the standard entropy change (0.023 J/mol.K) suggested that the Cu2+ adsorption onto IIP-Cu had a good affinity at the solid-liquid surface. The efficiency of the prepared IIP-Cu was also tested by studying the adsorption capacity using Sr2+ and real brine water. The results revealed that IIP-Cu was able to remove 63.57% of Sr2+ at pH 8. While the adsorption studies revealed that the experiment was best described using the Langmuir model with a maximum adsorption capacity of 76.92 mg/g. Additionally, IIP-Cu was applied in a real brine sample, which consisted of various metal ions. The highest percentage of Cu2+ removal was 90.6% and the lowest was 65.63% in 1:4 and 1:1 brine ratios, respectively. However, this study indicates the successful application of IIP-Cu in a real sample when it comes to the effective and efficient removal of Cu2+ in a solution consisting of various competing ions. • IIP-Cu was successfully fabricated using potassium persulfate as an initiator. • The prepared IIP-Cu demonstrated high affinity and selectivity towards Cu2+. • The maximum removal of 98.7% Cu2+ and 63.57%.Sr2+ was achieved at pH 8. • High desorption efficiencies for both Cu2+ and Sr2+ were achieved. • IIP-Cu showed excellent removal removals 90.6% Cu2+ and 82.6% Sr2+ from real brine. [ABSTRACT FROM AUTHOR]

Boron in high concentration levels leads to harmful effects on the environment and human health. Hence, it needs to be eliminated from desalinated water in order to improve water quality. As a result, the removal of boron from aqueous solution using waste eggshell as an adsorbent was investigated. Eggshell, as an agricultural waste, was studied as they are low cost and environmentally friendly, where the presence of calcium carbonate makes it an effective sorbent. The percent removal capacity of boron was studied under various experimental conditions including pH, initial boron concentration and temperature. Surface characterization, morphology and functional groups on the external surface of the adsorbent were investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). FTIR showed that the main functional groups were C O and Ca O on the surface of the eggshells, and SEM indicated changes in surface morphology where well-defined structure was observed after calcination. However, after adsorption of boron, no significant morphology changes were detected. Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models were used to determine the best-fit equation to represent the experimental data. Results showed that removal efficiency of boron was 96.3% at pH 6, and the adsorption processes for both waste eggshell and calcined eggshell were exothermic and spontaneous. [ABSTRACT FROM AUTHOR]

This study investigated the use of eggshell membrane (ESM) as a bio-sorbent and the effect of temperature, pH, and initial concentration on its efficiency. Furthermore, by altering the chemical composition, modified eggshell membrane (MESM) was prepared, and its efficiency was compared with the ESM. Results showed that the adsorption of boron preferred an acidic condition; pH 6 at 35 °C. In addition, the positive value of ΔH° suggested that the reaction favored endothermic pathway, while the negative value for ΔG° further suggested that the adsorption process was spontaneous. Furthermore, the ESM could adsorb 97% of boron, while MESM was able to adsorb 95%. From the Fourier transform infrared (FTIR), different functional groups were recorded on the surface of the ESM and MESM, and they played key role in the boron adsorption mechanisms. Linear Freundlich model was suggested to best describe the experimental data with 99.4% correlation coefficient. [ABSTRACT FROM AUTHOR]

Bromide ions (Br − ) are associated with toxic by-products that might be produced during the disinfection of drinking water. The removal of Br − from water using roasted date pits (RODPs) and activated carbon was investigated. The percentage removal capacity of Br − was studied under various experimental conditions including solution pH, adsorbent mass and particle size, and initial Br − concentration. Surface characterisation was investigated using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). SEMs images showed the presence of fine particles (debris) on the surface of the adsorbent solids. The raw date pits (RDPs) surface images showed a marked difference in pore sizes upon roasting, whilst FTIR spectra showed a slight shifting in –O–H, C O, and –C–O stretching in addition to –O–H bending for the RODPs. In addition to the Freundlich and Langmuir isotherm models, the experimental data were fitted to different adsorption kinetic models. It was found that the adsorption of Br − onto RODPs followed pseudo-second order mechanism. Removal rates of around 54% were obtained at lower pH. [ABSTRACT FROM AUTHOR]

The occurrence of chlorine dioxide (ClO 2 ) disinfection by-products (DBPs) in drinking water, namely, chlorite, chlorate, and trihalomethanes (THMs), was investigated. Two-hundred-ninety-four drinking water samples were collected from seven desalination plants (DPs), four reservoirs (R), and eight mosques (M) distributed within various locations in southern and northern Qatar. The ClO 2 concentration levels ranged from 0.38 to <0.02 mg L −1 , with mean values of 0.17, 0.12, and 0.04 mg L −1 for the DPs, Rs, and Ms, respectively. The chlorite levels varied from 13 μg L −1 to 440 μg L −1 , with median values varying from 13 to 230 μg L −1 , 77–320 μg L −1 , and 85–440 μg L −1 for the DPs, Rs, and Ms, respectively. The chlorate levels varied from 11 μg L −1 to 280 μg L −1 , with mean values varying from 36 to 280 μg L −1 , 11–200 μg L −1 , and 11–150 μg L −1 in the DPs, Rs, and Ms, respectively. The average concentration of THMs was 5 μg L −1 , and the maximum value reached 77 μg L −1 However, all of the DBP concentrations fell within the range of the regulatory limits set by GSO 149/2009, the World Health Organization (WHO), and Kahramaa (KM). [ABSTRACT FROM AUTHOR]

Prosopis juliflora (Sw.) DC. Is highly recognized for its invasive character and its detrimental effects on different plant species across the world. In this study, a field survey was performed to assess the impact of P. juliflora on the surrounding native plants, followed by the effect of different concentrations of its aqueous leaf extract on seed germination and seedling growth of selected Qatari flora. Our field observations indicated a high prevalence of new recruitments of P. juliflora than other native-associated plants in the study site. Germination percentage and/or seed radicle length of the test species: Acacia tortilis (Forssk.) Hayne, Prosopis cineraria (L.) Druce, Sueda aegyptica (Hasselq.) Aellen, Halopeplis perfoliata (Forssk.) Bunge ex Schweinf. & Asch, and P. juliflora were significantly (p ≤ 0.05) reduced by the extracts at different concentration levels. Moreover, the germination rate of A. tortilis was not affected; however, the seed germination of P. cineraria was significantly affected at concentrations of 6 and 8 mg mL−1. The seed radicle lengths at 2 mg mL−1 were significantly reduced for both plant species. The seed germination and radicle length of S. aegyptica and H. perfoliata were significantly decreased at 2 mg mL−1 of extract of P. juliflora. Furthermore, the height and biomass of the seedlings of Aeluropus lagopoides (L.) Trin. ex Thwaites, Caroxylon imbricatum (Forssk.), and Tetraena qatarensis (Hadidi) Beier & Thulin were significantly reduced by the aqueous extracts at 6 and 8 mg mL−1. The aqueous extract reduced the seed germination and seedling growth at 6 and 8 mg mL−1, indicating an autotoxic effect. Such allelopathic behavior of P. juliflora designates the potential investigation of using its allelochemicals as naturally based herbicides in agrosystems. [ABSTRACT FROM AUTHOR]

Abstract: Application of microemulsion modified raw date pits as an inexpensive solid extractant for removing methylene blue (MB), copper ion (Cu2+) and cadmium ion (Cd2+) has been presented. The results summarised herein are also part of an investigation conducted to evaluate the adsorption capacity by taking into consideration the experimental parameters such as pH, particle size and initial solute concentration. The experimental data obtained from the adsorption isotherms studies were used to find pollutants distribution factors and modelled using both Langmuir and Freundlich equations. The modified adsorbent was more effective toward all pollutants with high removal capacities (50–350 mg/g) and with very large distribution values (9–235 L/g) which indicates the suitability of this new material for extraction organic and inorganic pollutants. After microemulsion modification, the FTIR scans of the samples show clear differences in the position and intensity the characteristics bands of the raw date pits (RDP). Three mechanisms of the MB, Cu2+ and Cd2+ adsorption onto μE-MDP are possible: (i) adsorption by an electrostatic force of the anionic head group of the surfactant and the positive charge of the dye (MB+) or the metal ions (Cu2+ or Cd2+), (ii) adsorption by tail groups of the surfactant and the hydrophobic character of the MB molecules. The MB is a basic dye and has basic characteristics and therefore is expected to interact strongly with the anionic head groups of the surfactants (RCOO–). In the contrary, the Cu2+ and Cd2+ ions are not expected to interact by the tail groups of the surfactant where the ionic radii of these ions may explain the differences between Cu2+ (0.72 Å) and Cd2+ (0.99 Å) adsorption capacities and (iii) filling the channel (pores) of the RDP by dissolving in the microemulsion micelles. [Copyright &y& Elsevier]

Abstract: The treatment of wastes has become one of the most important concerns of modern society to protect the environment. Application of microemulsion modified raw local diatomite (μE-MD) and activated carbon (μE-MAC) as solid extractants for removing inorganic (iron, copper and lead ions) and organic pollutants (soot, oxidations, nitration and sulphation products) from waste lubricants (WL) at a moderate heat have been presented. The results summarised herein are also part of an investigation conducted to evaluate the adsorption removal by taking into consideration the experimental parameters such as initial pollutant concentration and temperature. The raw and modified adsorbents were effective towards all pollutants especially for the inorganic pollutants with high removal percentages (Fe: 34–68%, Cu: ∼65%, Pb: 55–80%) and (oxidation: 7–15%, nitration: 41–46%, sulphation: 5–29%, soot: 42–61%) which indicated the suitability of these new materials for extraction of organic and inorganic pollutants from non-aqueous WL medium. The removal percentages, however, varied from adsorbent to another“. The pHzpc (pH at point of zero charge) was carefully estimated for all adsorbents (raw diatomite (RD), μE-MD, activated carbon (AC), μE-MAC) and found to be (8.6, 7.8, 7.3, 9.1), respectively. The experimental results were also plotted and treated with Langmuir isotherm, uncommon isotherm shapes were obtained. Therefore, it was not fitted to the experimental results which might reflect a complex nature of adsorbing onto the adsorbents. However, this behaviour gave an indication on the complex adsorption mechanisms. Finally, the mode of interaction between the pollutants and the μE-MD and μE-MAC was characterised by comparing the changes in the position and intensity of the surface functional groups using the FTIR technique. Three mechanisms of the adsorption of organic (oxidation, nitration and sulphation) and inorganic (heavy metals) pollutants were possible: (i) adsorption by an electrostatic force of the anionic head group of the surfactant and the positive charge of the organic molecules or the cation metal, (ii) adsorption by tail groups of the surfactant and the hydrophobic character of the organic molecules. The cation heavy metals and the organic compounds have basic characteristics and therefore were expected to interact strongly with the anionic head groups of the surfactants (RCOO−). In the contrary, the cationic heavy metals were not expected to interact by the tail groups of the surfactant where the ionic radii of these ions may explain the differences between every metals removal percentage and (iii) filling the channel (pores) of the RD and the AC by dissolving in the microemulsion micelles. [Copyright &y& Elsevier]

Abstract: In Jordan, large amounts of fly ash (FA) are produced as a result of burning heavy fuel in power plants. Extraction of metals from FA is an important industrial/environmental issue to assess metals’ mobility and applications. Large amounts of metals (V, Ni, Fe, Ca, Mg, Na, and K) were easily leached from FA under acidic, basic, and neutral conditions and this makes disposal of this material an important environmental issue. Extraction and separation of vanadium (V) and nickel (Ni) from FA is achieved using Akita''s procedure with some modifications. In the first step, Ni is selectively eluted from FA using NH4OH solution and then precipitated using Na2S. The Ni/V ratio in final precipitate was 27. On the other hand, V is extracted from Ni-free-FA using Na2CO3 solution, recovered by 0.1M tri-ethylamine/toluene, and precipitated by NH4Cl. The V/Ni ratio in the final precipitate was 55. The adopted method showed a reasonable recovery for both metals from FA, 56 and 45% from Ni and V, respectively. The earlier attempts indicated that separation of V/Ni by precipitation using OH− or CO3 2− was not successful where both the metals did not precipitate from solution in the presence of other elements. [Copyright &y& Elsevier]

Abstract: The removal of organosulphur compounds (ORS) from diesel fuel is an important aspect of Jordanian''s effort to reduce air pollution by sulphur oxides. The results of this work revealed that activated carbon (AC) has an excellent adsorption for the ORS from non-aqueous diesel medium. Experimental data revealed that percentage removal of the ORS was slightly affected with particle size of the adsorbent, which indicates that elimination of the ORS mainly occurred on the external surface area and the adsorption onto the pores of the adsorbent has a small effect on the entire elimination process. Removal of the ORS by the AC has an endothermic nature where percentage removal values were increased by temperature. The maximum percentage removal value was 72% which was reported at: 2.0g, 300–500μm, 25°C, and 3 days shaking. The experimental results were plotted and treated with Langmuir isotherm, uncommon isotherm shapes were obtained. Therefore, it was not fitted to the experimental results which might reflect a complex nature of adsorbing the ORS onto the AC. However, this behaviour gives an indication on the complex adsorption mechanisms. Finally, the mode of interaction between the ORS and the AC was characterised by comparing the changes in the position and intensity of the surface functional groups using FTIR technique. [Copyright &y& Elsevier]

Abstract: In order to remove the limitations originating from inefficient heat and mass transfer in adsorption refrigeration/heat pump, an innovative arrangement design was proposed. It was equipped with meshed multi-tubular involving activated carbon in a sealed cylindrical adsorber. Related aspects of adsorption refrigeration key parameters were addressed. Working pair, activated carbon–diethyl ether, is used in the above system in order to determine the optimum adsorption refrigeration parameters. In order to estimate the adsorption characteristics and the adsorption capacity of the adsorbent, the adsorption isotherms of that adsorbent, with a specific adsorbate, are carried out. The measured adsorption data were adequately described by the Langmuir equation. The adsorption capacity of the diethyl ether on activated carbon at 26, 35, and 50°C were 0.0159, 0.0220, and 0.0188mmol/g, respectively. Two kinetic adsorption models namely pseudo-first and second order kinetic models were investigated. The thermodynamic parameters, ΔH°, entropy, ΔS°, and Gibbs free energy, ΔG°, of the adsorption process were also obtained from the gas adsorption experiments at various temperatures. These values were −45.84kJ/mol, −88.87J/(molK), and −19.27kJ/mol, respectively. The pseudo-first order model was not applicable in this adsorption system, suggesting that the adsorption process and the rate-limiting step was the pseudo-second order reaction. Therefore, the dominant mechanism might be a chemisorption process between the diethyl ether molecules and the activated carbon surface. The k 2, however, decreased as the initial diethyl ether pressure increased. [Copyright &y& Elsevier]

Abstract: The efficiency of iron coated activated alumina, ferric oxihydroxide and granular activated carbon for the removal of humic substance (HS) from water and wastewater was demonstrated in batch studies. This paper investigated the use of these successful adsorption–adsorbate systems in a continuous flow mode in an effort to obtain the required design and operational data; essential for successful application in water treatment works. The adsorbents were used individually. The influence of the various molecular mass fractions on the adsorption ability of the various systems was considered. Fractionation of humic substances was carried out and low, medium and high molecular mass fractions were produced. Two different column diameters (2.5 and 1cm) were used in the experimental runs. The smaller diameter column was used for experiments dealing with the lower molecular weigh humics as these are very difficult to produce in large enough quantities to carry out continuous adsorption runs in the traditional 2.5cm diameter laboratory adsorption columns. The dissolved organic content (DOC), ultraviolet (UV) absorbance and specific ultraviolet absorbance (SUVA) values were measure and analysed under different operating conditions. Furthermore, the experimental results were modelled using the Thomas model and the empty bed contact time model (EBCT). The Mass Transfer Zone was also analysed for all cases. The results indicated strongly the influence of molecular mass in the adsorption of humic substances. In addition, two distinctive features appear from these results; GAC is able to remove high MM although lacking of mesoporosity (attributed to precipitation and alteration of HS conformation) and β-FeOOH does not show such a high adsorption capacity as previously predicted, attributed to the non-equilibrium state and to the lack of surface under the media compaction. [Copyright &y& Elsevier]

The investigations into structural changes which occur during adsorbent modification and the adsorption mechanisms are essential for an effective design of adsorption systems. Manganese oxides were impregnated onto diatomite to form the type known as δ-birnessite. Initial investigations established the effectiveness of manganese oxides-modified diatomite (MOMD) to remove basic and reactive dyes from aqueous solution. The adsorption capacity of MOMD for methylene blue (MB), hydrolysed reactive black (RB) and hydrolysed reactive yellow (RY) was 320, 419, and 204mg/g, respectively. Various analytical techniques were used to characterise the structure and the mechanisms of the dye adsorption process onto MOMD such as Fourier transform infrared (FTIR), X-ray diffraction (XRD) and atomic absorption spectrometry (A.A.). A small shift to higher values of the d-spacing of dye/MOMD was observed indicating that a small amount of the dye molecules were intercalated in the MOMD structure and other molecules were adsorbed on the external surface of MOMD. Two mechanisms of dye adsorption onto MOMD were proposed; intercalation of the dye in the octahedral layers and adsorption of the dye on the MOMD external surface. Moreover, the results demonstrated that the MOMD structure was changed upon insertion of MB and RY with an obvious decrease in the intensity of the second main peak of the MOMD X-ray pattern. [Copyright &y& Elsevier]

Abstract: As a result of the changes that occur during their use, used engine oils tend to differ in chemical and physical composition from a virgin oil. In general recycled oils have: much higher water and sediment levels than virgin oil; relatively higher concentrations of organic compounds (oxidation products); and relatively higher levels of metals such as Fe, Cd, Cr, Pb, etc. Therefore, the aim of this work was to investigate, assess and to observe, by means of the physical and the chemical properties of the oils, atomic absorption (AA), inductive couple plasma (ICP) and Fourier transform infrared (FTIR) analyses the extent of the differences occurring between the virgin and recycled oil. In important part of this work was also the development of analytical techniques based on the use of FTIR spectroscopy; in relation to the rapid analysis of lubricants; in particular for the differentiation of virgin and recycled oil. The results obtained were expected to be useful for differentiation purposes, providing information on whether the metal concentrations and oxidation products could be an appropriate feature for differentiating a particular oil sample from the others. This work is categorized into a two-step procedure. Firstly, an evaluation of a typical FTIR spectrum of an engine oil sample (mono- and multigrade) is presented. The broad feature centered at 1716cm−1 is due to the presence of carbonyl containing degradation products of oil. A band observed at 1732, 1169, 1154 and 1270cm−1 assigned to the polymethacrylate stretching vibrations, allows the determination of viscosity modifier and pour point depressant additives. The observed differences in the specific spectral bands (1732, 1169, 1154 and 1270 and 1716cm−1) are investigated and discussed. Secondly, an analytical technique for the measurement of the levels of the wear metals is also applied. [Copyright &y& Elsevier]

Brine released from desalination plants is extremely high in salinity and contains various chemicals, which are harmful to the ecosystem. The disposal of brine has raised great concerns for the desalination industry around the world due to its detrimental impact on fauna and flora. This review complies with various zero liquid discharge technologies that have been proposed for successful brine disposal which aims to minimize the impact of brine discharge. Moreover, it highlights some of the detrimental impacts of brine discharge on marine fauna and Flora. It also discusses both thermal and membrane technologies for recovering freshwater, energy, and minerals from waste brine, in addition to the recent advances in a solar pond, membrane distillation, pressure retarded osmosis, etc. In Driver-Pressure-State-Impact-Response (DPSIR) framework was used in this review to analyze the water resource system in Qatar. This review also facilitates and provides a comprehensive approach in minimizing the potential impact of brine discharge which can be practiced and applied in countries where desalination plants are set up. This promotes cleaner production, sustainability, and recycling of waste that will help protect and preserve the country's natural water resources. [ABSTRACT FROM AUTHOR]

Computerised flow injection coupled with potentiometric stripping analysis (FIPSA) was employed for examination of the adsorption behaviour of Pb(II), Cd(II) and Zn(II) ions onto diatomite modified with manganese oxides. Signal optimisation was undertaken with respect to flow rate, deposition time, deposition potential, oxidising agent concentration, thickness of mercury film, solution pH and metal ion concentration. Examination of the column adsorption characteristics was facilitated by introduction of an adsorption microcolumn, as a complementary component of the flow injection system. The resulting breakthrough curves were employed to calculate parameters including adsorption capacity and adsorption rate constant, taking into consideration initial ion concentration, flow rate, mass and particle size of adsorbent, and column internal diameter. Adsorption capacities, determined using the Thomas mathematical model, showed that manganese modified Jordanian diatomite had an efficiency towards the removal of heavy metal ions from aqueous solutions; Cd(II)>Zn(II)≉Pb(II). The relative adsorption rates of the ions followed the order: Pb(II)>Zn(II)≉Cd(II). [Copyright &y& Elsevier]

This paper investigated the development and evaluation of an extraction process for copper, chromium, cobalt, iron, manganese, zinc, lead, cadmium, barium, magnesium, and vanadium from municipal solid waste incineration ash (bottom and fly ashes) based on microwave-assisted acid extraction method. In this study, a novel conventional microwave-mediated technique was applied by using various acidic extracting agents, namely, hydrochloric acid, nitric acid, and phosphoric acid. Several experimental conditions and parameters were modified and optimized to determine the most effective conditions for maximizing metal extraction. The results were also compared with our preliminary research, which investigated the optimization of conventional heating for extracting the same metals. The current study concluded that the microwave-assisted acid extraction method was much more effective than conventional heating. The metals from the bottom ash were much easier to extract in contrast with the fly ash. For the bottom ash, 71 wt% of Co, 75.69 wt% of Cr, 56.19 wt% of Cd, 35.23 wt% of Ba, 30.2 wt% of Pb, and 5.41 wt% of Mn were effectively extracted using the protocol C (2 M HCl and 3 M H 3 PO 4). 13.87 wt% of Al, 10.59 wt% of Cu, 7.2 wt% of Fe, 5.25 wt% of Mg were also extracted using the protocols D and E (3 M HNO 3 and 3 M H 2 O 2) from MSW-BA. On the other hand, for the fly ash, 2.27 wt% of Cu, 0.93 wt% of Fe, 2.32 wt% of Zn, 6.28 wt% of Cd, 1.98 wt% of Ba, 3.46 wt% of Mg and 4.7 wt% of V were extracted by using the protocol A (5 M HCl and 5 M HNO 3). 1.48 wt% of Cr, 0.93 wt% of Fe, 1.19 wt% of Mn, and 1.18 wt% of Al were extracted using the protocol C (2 M HCl and 3 M H 3 PO 4). It was also confirmed that higher microwave power levels had a positive effect on the metal extraction, and longer contact times had an adverse effect. When comparing the cost analyses for both methods, it was found that the microwave-assisted acid extraction was less expensive than the conventional heating. The present study offers a promising method, which is simple and cost-effective and presents a minimal environmental risk to extract metals from municipal solid waste incineration ash. Image 1 [ABSTRACT FROM AUTHOR]

This paper investigates the development of stable geopolymers using petroleum fly ash with high compressive strength and water absorption to promote cleaner production, sustainability, and recycling of waste. The paper provided detailed characterizations of the petroleum fly ash, which involved the determination of the particle size diameter, density, surface area, pore-volume, mineralogical identification of recording X-ray diffraction pattern, X-ray fluorescence, Fourier transform infrared, thermogravimetric analysis, and scanning electron microscope. Moreover, metals leachability from the petroleum fly ash using different extracting agents, namely H 2 SO 4 , H 3 PO 4 , (NH 4) 2 SO 4 , NH 4 NO 3 , and NH 4 O 2 CCO 2 H was also considered. Five geopolymers were prepared using different amounts of petroleum fly ash to assess the influence of petroleum fly ash on the final performance of the prepared geopolymers. The results revealed that the petroleum fly ash was carbonaceous in nature and rich in vanadium oxide and nickel oxide with low in SiO 2 and Al 2 O 3. Furthermore, it was found that petroleum fly ash has a low calcium level. The maximum extraction values were 15.6% for V and 55.6% for Ni using H 2 SO 4. All the prepared geopolymers displayed high compressive strength for longer curing times, and the water absorption properties of all geopolymers were improved by incorporating more petroleum fly ash. Increasing the petroleum fly ash from 0 vol% to 61 vol% increased the water absorption value from 6.6 to 13.3 wt% for the samples collected after 28 days of curing. It was concluded that the petroleum fly ash did tend to form successful stable geopolymers with high compressive strength and water absorption. [ABSTRACT FROM AUTHOR]

In the current study, the mechanistic understanding of the adsorption isotherm and thermodynamic aspects of cationic methylene blue (MB) dye adsorption onto cellulosic olive stones biomass from wastewater were investigated. The batch adsorption of MB onto the olive stones (black and green olive stones) was tested at a variety of pH, dye concentrations, temperatures, and biomass particle sizes. The adsorption thermodynamics such as Gibbs free energy, enthalpy, and entropy changes were also calculated. Moreover, the desorption studies of MB from the spent olive stones were studied to explore the re-usability of the biomasses. The results revealed that under the optimum pH of 10, the maximum MB uptake was achieved i.e. 80.2% for the green olive stones and 70.9% for the black olive stones. The green olive stones were found to be more efficient in remediating higher MB concentrations from water than the black olive stones. The highest MB removal of the green olive stones was achieved at 600 ppm of MB, while the highest MB removal of the black olive stones was observed at 50 ppm of MB. Furthermore, for almost all the concentrations studied (50–1000 ppm), the MB adsorption was the highest at the temperature of 45 °C (P value < 0.05). It was shown by the Fourier transform infrared that the electrostatic interaction and hydrogen bonding were proposed as dominant adsorption mechanisms at basic and acidic pH, respectively. While the hydrophobic-hydrophobic interaction was a dominant mechanism at neutral pH. The thermodynamic studies revealed that the adsorption process was endothermic, spontaneous, and favorable. Moreover, the real wastewater experiment and the desorption studies showed that the green and black olive stones were a cost-effective and promising adsorbents for MB remediation from wastewater on account of their high adsorption and desorption removal capacities. [ABSTRACT FROM AUTHOR]

The current work presented here focuses on the remediation of mercury from water using modified low-cost materials. Modified date pits, low cost, minimal pretreatment steps and locally abundant agricultural waste materials were effectively employed as an adsorbent for remediating Hg2+ from aqueous media. Physical and chemical modification were developed such as thermal roasting (RDP), sulfur (SMRDP) and silane (SIMRDP) based modifications. Results showed that maximum adsorption by RDP was at pH 6, AC and both modifications was at pH 4. Furthermore, RDP has exothermic adsorption mechanism while AC, SMRDP, and SIMRDP have endothermic. All adsorbents except SIMRDP have spontaneous adsorption process. SEM analysis showed that the surface morphology of RDP was not significantly affected by different treatments while surface of AC was affected. The investigation for good adsorbents for Hg2+ uptake from different anthropogenic sources has been carried out by many investigators worldwide towards having a safe environment. In the current study, the highest Hg2+ adsorption of SMRDP was relatively high compared to other known adsorbents. [ABSTRACT FROM AUTHOR]

The aims of this study were to investigate the vertical distributions of natural radionuclides 232Th, 226Ra and 40K as well as anthropogenic radionuclide 137Cs in soil samples and to analyze the correlation among the radioactivity of these radionuclides and the physiochemical characteristics of soil samples namely pH, grain size, carbonate content and organic matter. Risk assessment of the radiological hazard has also been estimated. Forty-four soil samples were collected from eleven locations in Qatar at four depth levels from 0 to 16 cm. The average concentrations of 232Th, 226Ra, 40K and 137Cs in the soil depth of 16 cm were 10, 17, 201 and 4 Bq/kg, respectively, which were within the reported world mean. The external absorbed gamma dose rate, the annual effective dose, the mean radium equivalent activity, the external hazard index and the lifetime cancer risk were 22 nGy/h, 0.027 mSv/y, 47 Bq/kg, 0.125 and 0.096 × 10−3, respectively. These values were far below the minimum recommended international values. The level of radioactivity concentrations in the soil was affected by the physiochemical characteristics of the soil. The positive correlation with highest R2 value was found among the radioactivity concentrations of 232Th and 40K and the soil clay content. Total organic carbon was also positively correlated for 226Ra and 137Cs activity concentrations, whereas, carbonate content was negatively correlated with the radioactivity concentrations of 232Th and 40K. As far as soil moisture content is concerned, the positive correlation with highest R2 value was obtained for 226Ra activity concentrations. [ABSTRACT FROM AUTHOR]

Abstract In this study, ten bacterial strains were found to be mercury resistant after their isolation from Qatari coastal sediments. Tolerance was found to be up to 100–150 ppm for five strains. Those strains had optimum growth conditions at salinity level of 10 ppm NaCl and pH 7–8. Starting from a concentration 7.9 ppm of mercury extracted from fluorescent lamps and after 6 days of incubation at 37 °C, two isolated strains HA6 (Bacillus spp.) and HA9 (Acinetobacter sp.) showed 96.7% and 98.9% of mercury bio-uptake efficiency, respectively. Other strains were capable of removing more than 60% of extracted mercury. Highlights • Bacillus spp. and Acinetobacter sp. showed 96.7% and 98.9% Hg removal. • Other strains were capable of removing more than 60% of extracted mercury. • Almost all strain exhibited the highest growth density at pH level between 7 and 8. • Acinetobacter sp. was able to be tolerant up to 200 ppm of mercury. • Such strains can be applied in bioremediation of highly mercury-polluted areas. [ABSTRACT FROM AUTHOR]

Gas hydrate blockage is a major issue that the production and transportation processes in the oil/gas industry faces. The formation of gas hydrates in pipelines results in significant financial losses and serious safety risks. To tackle the flow assurance issues caused by gas hydrate formation in the pipelines, some physical methods and chemical inhibitors are applied by the oil/gas industry. The physical techniques involve subjecting the gas hydrates to thermal heating and depressurization. The alternative method, on the other hand, relies on injecting chemical inhibitors into the pipelines, which affects gas hydrate formation. Chemical inhibitors are classified into high dosage hydrate inhibitors (thermodynamic hydrate inhibitors (THI)) and low dosage hydrate inhibitors (kinetic hydrate inhibitors (KHI) and anti-agglomerates (AAs)). Each chemical inhibitor affects the gas hydrate from a different perspective. The use of physical techniques (thermal heating and depressurization) to inhibit hydrate formation is studied briefly in this review paper. Furthermore, the application of various THIs (alcohols and electrolytes), KHIs (polymeric compounds), and dual function hydrate inhibitors (amino acids, ionic liquids, and nanoparticles) are discussed thoroughly in this study. This review paper aims to provide a complete and comprehensive outlook on the fundamental principles of gas hydrates, and the recent mitigation techniques used by the oil/gas industry to tackle the gas hydrate formation issue. It hopes to provide the chemical engineering platform with ultimate and effective techniques for gas hydrate inhibition. [ABSTRACT FROM AUTHOR]

Activated carbons prepared from walnut and poplar woods are used as economical adsorbents for the rapid removal and fast adsorption of Acid Red 18 dye from the aqueous solutions; the kinetics, isotherm and thermodynamics studies of the process were well investigated and elucidated. The adsorption phenomenon may be possibly attributed to the formation of various binding bonds between the activated carbons, developed from the poplar and walnut woods, surface and the dye molecules; adsorption may firstly take place on the external surface of the developed adsorbent i.e. activated carbon developed from the walnut and poplar wood particles, where the attached functional groups play a crucial role in the rapid removal and fast adsorption. Secondly, adsorption may take place on the entire surface, which leads to a uniform distribution of adsorbed Acid Red 18 molecules onto the developed adsorbents. Forces that are responsible for the main adsorption mechanism are π–π attraction between Acid Red 18 dye molecules and the C C bonds of the developed adsorbents. Consequently, at least three types of adsorption sites might occur on the adsorbent surface; these are basal plane, edge plane and micropores. Neither pseudo-first order kinetic model nor pseudo-second order kinetic model was able to describe the adsorption process of AR18 molecules onto the activated carbon from poplar wood. [ABSTRACT FROM AUTHOR]

Pesticides are used in agriculture to protect crops from pathogens, insects, fungi and weeds, but the release of pesticides into surface/groundwater by agriculture runoff and rain has raised serious concerns not only for the environment but also for human health. This study aimed to investigate the impact of surface properties on the performance of seven distinct membrane types utilized in nanofiltration (NF), reverse osmosis (RO) and forward osmosis (FO) processes in eliminating multiple pesticides from spiked water. Out of the membranes tested, two are self-fabricated RO membranes while the rest are commercially available membranes. Our results revealed that the self-fabricated RO membranes performed better than other commercial membranes (e.g., SW30XLE, NF270, Duracid and FO) in rejecting the targeted pesticides by achieving at least 99% rejections regardless of the size of pesticides and their log K ow value. Despite the marginally lower water flux exhibited by the self-fabricated membrane compared to the commercial BW30 membrane, its exceptional ability to reject both mono- and divalent salts renders it more apt for treating water sources containing not only pesticides but also various dissolved ions. The enhanced performance of the self-fabricated RO membrane is mainly attributed to the presence of a hydrophilic interlayer (between the polyamide layer and substrate) and the incorporation of hydrophilic nanosheets in tuning its surface characteristics. The findings of the work provide insight into the importance of membrane surface modification for the application of not only the desalination process but also for the removal of contaminants of emerging concern. [Display omitted] • Membrane rejection against pesticides varied depending on its physiochemical properties. • RO membranes showed the highest pesticides rejection followed by NF and FO membranes. • Improving surface properties of RO membranes using GO further enhanced pesticides removal. • GO-modified RO membrane achieved >99% rejections regardless of pesticide size and log K ow. [ABSTRACT FROM AUTHOR]

There is no doubt that infectious diseases present global impact on the economy, society, health, mental state, and even political aspects, causing a long-lasting dent, and the situation will surely worsen if and when the viral spread becomes out of control, as seen during the still ongoing coronavirus disease 2019 (COVID-19) pandemic. Despite the considerable achievements made in viral prevention and treatment, there are still significant challenges that can be overcome through careful understanding of the viral mechanism of action to establish common ground for innovating new preventative and treatment strategies. Viruses can be regarded as devil nanomachines, and one innovative approach to face and stop the spread of viral infections is the development of nanoparticles that can act similar to them as drug/vaccine carriers. Moreover, we can use the properties that different viruses have in designing nanoparticles that reassemble the virus conformational structures but that do not present the detrimental threats to human health that native viruses possess. This review discusses the current preventative strategies (i.e., vaccination) used in facing viral infections and the associated limitations, highlighting the importance of innovating new approaches to face viral infectious diseases and discussing the current nanoapplications in vaccine development and the challenges that still face the nanovaccine field. [ABSTRACT FROM AUTHOR]

Highlights: [•] The uptake capacity order was: Pb2+ >Cu2+ >Ni2+. [•] The thermodynamic constants were endothermic and spontaneous for Pb2+ and Cu2+. [•] The thermodynamic constants were exothermic and non-spontaneous for Ni2+. [•] The adsorption mechanisms are affected by metal ion hydration and other factors. [•] Different functional groups are responsible on the metals binding. [Copyright &y& Elsevier]

Bacteria play a variety of roles in the environment. They maintain the balance in the ecosystem and provide different ecosystem services such as in biogeochemical cycling of nutrients, biodegradation of toxic pollutants, and others. Therefore, isolation and identification of different environmental bacteria are important to most environmental research. Due to the high cost and time associated with the conventional molecular techniques, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has gained considerable attention for routine identification of bacteria. This review aims to provide an overview of the application of MALDI-TOF MS in various environmental studies through bibliometric analysis and literature review. The bibliometric analysis helped to understand the time-variable application of MALDI-TOF MS in various environmental studies. The categorical literature review covers various environmental studies comprising areas like ecology, food microbiology, environmental biotechnology, agriculture, and plant sciences, which show the application of the technique for identification and characterization of pollutant-degrading, plant-associated, disease-causing, soil-beneficial, and other environmental bacteria. Further research should focus on bridging the gap between the phylogenetic identity of bacteria and their specific environmental functions or metabolic traits that can help in rapid advancements in environmental research, thereby, improving time and cost savings. • It provides an overview of MALDI-TOF MS applications in environmental studies. • Isolation and identification of environmental bacteria are important to environmental research. • MALDI-TOF MS has high accuracy and precision for the identification of various types of bacteria. • It is used for rapid identification of bacteria present in water, air, and different surfaces. [ABSTRACT FROM AUTHOR]

A simple temperature-assisted solution interaction technique was used to functionalize and reduce graphene oxide (GO) using tetraethylenepentamine (TEPA) with less chemicals, low temperature, and without using other reducing agents. GO nanosheets, produced using a modified Hummers' method, were functionalized using two different GO:TEPA ratios (1:5 and 1:10). The reduction of GO was evaluated and confirmed by different spectroscopic and microscopic techniques. The FTIR and XPS spectra revealed that most of the oxygenated groups of GO were reduced. The emergence of amide groups in the XPS survey of the rGO-TEPA samples confirmed the successful reaction of TEPA with the carboxyl groups on the edges of GO. The replacement of the oxygenated groups increased the carbon/oxygen (C/O) ratio of GO by approximately 60%, suggesting a good reduction degree. It was found that the I2D/ID+D′ ratio and the relative intensity of the D″ band clearly increased after the reduction reaction, suggesting that these bands are good estimators for the reduction degree of GO. The morphological structure of GO was also affected by the reaction with TEPA, which was confirmed by SEM and TEM images. The TEM images showed that the transparent GO sheets became denser and opaque after functionalization with TEPA, indicating an increase in the stacking level of the GO sheets. This was further confirmed by the XRD analysis, which showed a clear decrease in the d-spacing, caused by the removal of oxygenated groups during the reduction reaction. [ABSTRACT FROM AUTHOR]

Highlights: [•] Competitive sorption of two cationic dyes of significant spectral overlapping is studied using MVC. [•] Simultaneous determination of two dyes (spectral overlap 96.4%) is achieved using PLS1. [•] Irregular L2-isotherm shape was observed for dyes sorption in binary systems. [•] Langmuir model was found applicable for presenting competitive sorption of cationic dyes. [•] Competitive sorption process of cationic dyes was found exothermic and spontaneous. [Copyright &y& Elsevier]

To address the problem of ever-increasing oily wastewater management, due to its directional liquid transport property, membranes with asymmetric wettability can be effectively used for emulsion separation. This study reports the synthesis of electrospun polymer–clay nanocomposite nanofibers, using co-polyamide polymer (COPA) and halloysite nanotubes (HA) as filler. The influence of clay content on the morphological, thermal and dielectric properties of the polymer composite nanofiber was investigated comprehensively to address the material characteristics of the developed system. The surface structure analysis and contact angle measurements of the electrospun composite nanofibers confirms the change in surface roughness and wettability when the fillers are added to the polymer. The porosity of the composite electrospun nanofiber membrane was found to be 85% with an oil adsorption capacity of 97% and water permeability of 6265 L/m2 h. Furthermore, the asymmetric wettability-driven oil/water emulsion separation abilities of the as-synthesized membranes shows that the separation efficiency of the composite fiber membrane is 10% improved compared to that of the neat fiber membrane, with improved separation time. [ABSTRACT FROM AUTHOR]

In this paper, novel composite materials from modified roasted date pits using ferrocyanides were developed and investigated for the recovery of lithium ions (Li+) from seawater reverse osmosis (RO) brine. Two composite materials were prepared from roasted date pits (RDP) as supporting material, namely potassium copper hexacyanoferrate-date pits composite (RDP-FC-Cu), and potassium nickel hexacyanoferrate-date pits composite (RDP-FC-Ni). The physiochemical characterization of the RO brine revealed that it contained a variety of metals and salts such as strontium, zinc, lithium, and sodium chlorides. RDP-FC-Cu and RDP-FC-Ni exhibited enhanced chemical and physical characteristics than RDP. The optimum pH, which attained the highest adsorption removal (%) for all adsorbents, was at pH 6. In addition, the highest adsorption capacities for the adsorbents were observed at the initial lithium concentration of 100 mg/L. The BET surface area analysis confirmed the increase in the total surface area of the prepared composites from 2.518 m2/g for RDP to 4.758 m2/g for RDP-FC-Cu and 5.262 m2/g for RDP-FC-Ni. A strong sharp infrared peak appeared for the RDP-FC-Cu and RDP-FC-Ni at 2078 cm−1. This peak corresponds to the C≡N bond, which indicates the presence of potassium hexacyanoferrate, K4[Fe(CN)6]. The adsorption removal of lithium at a variety of pH ranges was the highest for RDP-FC-Cu followed by RDP-FC-Ni and RDP. The continuous increase in the adsorption capacity for lithium with increasing initial lithium concentrations was also observed. This could be mainly attributed to enhance and increased lithium mass transfer onto the available adsorption active sites on the adsorbents' surface. The differences in the adsorption in terms of percent adsorption removal were clear and significant between the three adsorbents (P value < 0.05). All adsorbents in the study showed a high lithium desorption percentage as high as 99%. Both composites achieved full recoveries of lithium from the RO brine sample despite the presence of various other competing ions. [ABSTRACT FROM AUTHOR]

Gas-to-liquid (GTL) sludge is a specific wastewater treatment by-product, which is generated during the industrial process of natural gas conversion to transportation fuels. This least studied sludge is pathogen-free and rich in organic carbon and plant nutrients. Therefore, it can be reused for soil enhancement as a sustainable management strategy to mitigate landfill gas emissions. In this field study, we compared the performance of soil treatments with GTL sludge to the more conventional chemical fertilizers and cow manure compost for the cultivation of cotton under hyperarid conditions. After a complete growing season, GTL sludge application resulted in the enhancement of soil properties and plant growth compared to conventional inputs. As such, there was a significant dose-dependent increase of soil organic matter (4.01% and 4.54%), phosphorus (534 and 1090 mg kg−1), and cumulative lint yield (4.68 and 5.67 t ha−1) for GTL sludge application rates of 1.5% and 3%, respectively. The produced fiber quality was adequate for an upland cotton variety (Gossypium hirsutum var. MAY 344) and appeared more dependent on the prevailing climate conditions than soil treatments. On the other hand, the adverse effects generally related to industrial sludge reuse were not significant and did not affect the designed agro-environmental system. Accordingly, plants grown on GTL sludge-amended soils showed lower antioxidant activity despite significant salinity increase. In addition, the concentrations of detected heavy metals in soil were within the standards' limits, which did not pose environmental issues under the described experimental conditions. Leachate analysis revealed no risks for groundwater contamination with phytotoxic metals, which were mostly retained by the soil matrix. Therefore, recycling GTL sludge as an organic amendment can be a sustainable solution to improve soil quality and lower carbon footprint. To reduce any environmental concerns, an application rate of 1.5% could be provisionally recommended since a two-fold increase in sludge dose did not result in a significant yield improvement. [Display omitted] • Gas-to-liquid sludge is a carbon-rich by-product of GTL wastewater treatment. • GTL sludge land application mitigates the risks of landfill gas emissions. • GTL sludge improves soil and plant properties under hyperarid conditions. [ABSTRACT FROM AUTHOR]

High-oxidation-degree graphene oxide particles were synthesized using a modified Hummers' method. Six different types of particles were synthesized by varying the operating conditions, including the temperature, the reactant ratios, and the oxidation time. The oxidation degree, represented by the oxygen content, and the atomic oxygen/carbon (O/C) ratio were determined using CHNSO elemental analysis, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy-universal attenuated total reflectance sensor (FTIR-UATR) and Raman spectroscopy. The structural morphology of graphene oxide was evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal stability of the particles was studied using thermogravimetric analysis (TGA). The SEM images showed that the prepared GO samples had different graphitic layer structures. The TEM images showed different stacking levels and transparency of GO flakes caused by the difference in oxidation level. The oxygen content and O/C ratios ranged between 34.7 and 50.0 wt% and 0.43 and 0.8, respectively. The highest oxygen content and O/C ratio were found to be 50 wt% and 0.8, respectively, for GO prepared at 95 °C with a 1-hr reaction time (GO2-a). A quantitative analysis on the FTIR-UATR spectra was performed and was in reasonable agreement with the CHNSO analysis results. The Raman spectra showed two characteristic bands (D and G) with different relative intensities, as characterized by the I D /I G ratio, suggesting that the prepared samples had different crystallite sizes and defects. The crystallite size (L a) of the prepared GO particles was estimated using the Tuinstra-Koenig model and were ranging between 9 and 24 nm. The TGA results were correlated with the elemental analysis results and showed a clear dependence of the weight loss on the GO elemental compositions. GO2-a exhibited the lowest thermal stability because of a high oxygen content, whereas GO1-b exhibited the highest thermal stability. Image 1 [ABSTRACT FROM AUTHOR]

Because of the high production of oil and gas in Qatar, the likelihood of oil spill occurrence is most probably susceptible to happen. Contaminated soil treatment is very expensive. Cost effective mechanisms are investigated to treat this threatening issue. For that reason, bioremediation and biotechnology tools are introduced to help accelerate and remove the pollution caused by the contamination process. This paper demonstrated the importance of optimising the treatment conditions to the indigenous bacterial strain to obtain the highest biodegradation efficiency rates. The usage of biopile system technology was used with biostimulation and bioaugmentation processes. The indigenous Bacillus sonorensis (B. sonorensis) D1 bacterium played a crucial role in the biodegradation process when introduced to optimized conditions; carbon/nitrogen/phosphorus (C/N/P) (100/10/1), temperature (37 °C), surfactant tween 80 (0.12% (v/w)), and moisture (10%). Gas chromatography (mass spectrometry/flame ionization detector) (GC- (MS/FID)), Fourier transform infrared (FTIR), and colony-forming unit (CFU) analyses were performed. The diesel range organics (DRO) and polycyclic aromatic hydrocarbons (PAH) removal (%) of the weathered oil contaminated soil reached, after 160 days, 39.2% and 32.4% simultaneously when ammonium nitrate was used as a nitrogen source. Whereas urea inhibited the oil degradation process and caused the pH to rise to 9.55. Image 1040 • Urea inhibited oil degradation process and caused pH to rise to 9.55 • Adding the surfactant tween 80 to urea enhanced bacterial growth with urea. • The bioavailability of the hydrocarbons is not always related to bacterial growth. • B. sonorensis D1 was able to biodegrade weathered oil at optimized conditions. • Using ammonium nitrate as a nitrogen source improved the biodegradation process. [ABSTRACT FROM AUTHOR]

Phenol is a priority pollutant that presents a significant threat to human health and natural systems when discharged directly into the environment. Consequently, numerous technologies have been used and developed to eliminate phenol from wastewater streams. These technologies can be categorized into physical, chemical, and biological methods. While conventional treatment methods are highly efficient in phenol removal; some of these techniques are not environmentally friendly and others are expensive. Therefore, sustainable, and green technologies are being employed and taken into consideration in the treatment of phenol wastewater due to their effectiveness, affordability, and environmental compatibility. This review aims to highlight efficient green physiochemical and biological methods of water treatment and demonstrate the mechanisms of phenol removal in these technologies. Particular emphasis will be given to the use of low-cost adsorbents prepared from industrial and agricultural wastes for the efficient removal of phenol from wastewater as adsorption processes show the highest cost-effectiveness among all the treatment technologies. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the applicability of the adsorption process for the removal of organophosphorus pesticide malathion 57% from water by using multi-walled carbon nanotubes (MWCNTs). The impact of various experimental conditions such as pH, quantity of adsorbent, concentration of pesticides, contact time and temperature was studied and optimized for the maximum removal of malathion. Unlike conventional optimization, a limited number of experiments (26 steps) were performed in a cost-effective manner for different independent variables such as MWCNTs concentration (0.1–0.5 g/L), the malathion (57%) concentration (6 mg/L and 10 mg/L), contact time (2–30 min) and pH (neutral range). Based on the experimental data obtained in a lab-scale batch study, a three-factor response surface modeling (RSM) approach was implemented in order to optimize the conditions for maximum removal of malathion, and compare experimental results with standardized malathion samples. The optimized conditions to achieve the maximum removal of malathion (100%) were determined to be a malathion concentration of 6 mg/L, an initial MWCNTs concentration of 0.5 g/L, and a contact time of 30 min. Findings of this study clearly indicated that 100% of the malathion could be cost-effectively removed by MWCNTs in conditions predicted by the proposed optimization methodology. [ABSTRACT FROM AUTHOR]

In this study, three types of adsorbents were used to remove and recover strontium ions (Sr2+) from aqueous and brine solution of seawater reverse osmosis (SWRO), namely roasted date pits (RDP) and RDP modified using copper and nickel salts of potassium hexacyanoferrates to obtain RDP–FC–Cu, and RDP–FC–Ni, respectively. Additionally, the influence of various parameters, including pH, temperature, initial concentration, and co-existing ions was also evaluated. The results revealed that pH 10 was the optimum pH in which the maximum Sr2+ ions were adsorbed. Additionally, all adsorbents had a high adsorption capacity (99.9 mg/g) for removing Sr2+ ions at the highest concentration (100 mg/L) and a temperature of 45 °C was found to be the optimum temperature. A scanning electron microscopy for the adsorbents before and after the adsorption of strontium showed the remarkable pore filling onto the active sites of all adsorbents. The thermodynamics parameter demonstrated that the adsorption occurred in an endothermic environment, and that, the reaction was spontaneous, and favorable at all the temperatures investigated. According to isotherm studies, the Langmuir model was the best-fit isotherm model; indicating that strontium adsorption involved the formation of monolayers and multilayers at higher temperatures (45 °C). Furthermore, high desorption percentages (above 90%) were achieved for all the adsorbents when an HCl concentration of 0.5 M was used. This showed the high reusability of the adsorbents. Lastly, the adsorption of strontium from the SWRO brine containing a number of metal ions was extremely sufficient as all the adsorbents were efficient to adsorb a high amount of Sr2+ despite the presence of other competing ions. [Display omitted] • Three adsorbents were investigated to remove and recover strontium ions (Sr2+) from brine solution. • PH 6 was the optimum pH in which the maximum Sr2+ was adsorbed. • 99.9 mg/g adsorption capacity was achieved for all adsorbents at the concentration of 100 mg Sr2+/L and 45 °C. • >90% desorption percentages were achieved for all the adsorbents at 0.5 M HCl. [ABSTRACT FROM AUTHOR]

The vast demand for petroleum industry products led to the increased production of oily wastewaters and has led to many possible separation technologies. In addition to production-related oily wastewater, direct oil spills are associated with detrimental effects on the local ecosystems. Accordingly, this review paper aims to tackle the oil spill cleanup issue as well as water separation by providing a wide range of graphene-based technologies. These include graphene-based membranes; graphene sponges; graphene-decorated meshes; graphene hydrogels; graphene aerogels; graphene foam; and graphene-coated cotton. Sponges and aerogels modified by graphene and reduced graphene oxide demonstrated effective oil water separation owing to their superhydrophobic/superoleophilic properties. In addition, oil particles are intercepted while allowing water molecules to penetrate the graphene-oxide-coated metal meshes and membranes thanks to their superhydrophilic/underwater superoleophobic properties. Finally, we offer future perspectives on oil water separation that are hindering the advancements of such technologies and their large-scale applications. [ABSTRACT FROM AUTHOR]

Nanomaterials have emerged as the new future generation materials for high-performance water treatment membranes with potential for solving the worldwide water pollution issue. The incorporation of nanomaterials in membranes increases water permeability, mechanical strength, separation efficiency, and reduces fouling of the membrane. Thus, the nanomaterials pave a new pathway for ultra-fast and extremely selective water purification membranes. Membrane enhancements after the inclusion of many nanomaterials, including nanoparticles (NPs), two-dimensional (2-D) layer materials, nanofibers, nanosheets, and other nanocomposite structural materials, are discussed in this review. Furthermore, the applications of these membranes with nanomaterials in water treatment applications, that are vast in number, are highlighted. The goal is to demonstrate the significance of nanomaterials in the membrane industry for water treatment applications. It was found that nanomaterials and nanotechnology offer great potential for the advancement of sustainable water and wastewater treatment. [ABSTRACT FROM AUTHOR]

This study evaluated biosolid quality over time and the efficiency of using amounts (5 and 7 kg/m2) of municipal class A biosolids in Qatar to fertilize tomato plants (Solanum lycopersicum). Random samples were subjected to physical and chemical analysis, which revealed excellent particle uniformity and stability with minor odor defects. The analysis confirmed the product was nutrient-rich while pollutant levels were below the international standards. The nominated rates were used to fertilize tomato plants in pots grown in a greenhouse for four months with a control treatment of manure and Peat-Moss, before measuring the plant biological characteristics. Plants were examined via chemical analysis of nutrients and pollutants both for the whole plant and for stems, fruits, and leaves. Results indicated that both experimental treatments enhanced plant growth and development as compared to the control treatment. However, the chemical analyses also revealed levels of zinc, copper, and manganese in the plant fruits that were well in excess of the maximum acceptable levels, as defined by international health organizations. This study found that while the application of class A biosolids as organic fertilizer for tomato plants greatly enhanced the overall plant growth, the plant fruits contained toxic levels of trace heavy metals. [ABSTRACT FROM AUTHOR]

[Display omitted] • Review of the limited use of ionic liquids (IL) in wastewater treatment and synthesis of biofuels is given. • Separation of the ILs from the solvent poses economic problems. • IL catalyst with high Bronsted Acidic value used for feedstock with high fatty acid content. • Use of ILs for wastewater treatment and biofuel provides several benefits. • Technological development is required to support IL commercial application. Commonly described as ionic compounds that are fluid below 100 °C, Ionic Liquids (ILs) have found its application in several fields of science and engineering. Formerly limited in its use for electrochemical purposes, ILs today have applications in wide and myriad fields. Among their numerous uses, the current water scarcity and rapid depletion of non-renewable fuel sources have directed the importance of ILs to wastewater treatment and production of biofuels. The versatility and stability of ILs have resulted in several studies dedicated to their optimization and practical application in the afore-mentioned fields. This review paper aims to provide a summary of the ILs studied for wastewater management for the extraction of organic pollutants as well as metal contents. It further details the ILs used to produce biodiesel through transesterification of various feedstocks. [ABSTRACT FROM AUTHOR]

Produced water is responsible for the largest contribution in terms of waste stream volume associated with the production of oil and gas. Characterization of produced water is very crucial for the determination of its main components and constituents for optimal selection of the treatment method. This review aims to review and critically discuss various treatment options that can be considered cost-efficient and environmentally friendly for the removal of different pollutants from produced water. Great efforts and progresses were made in various treatment options, including batch adsorption processes, membrane filtration, advanced oxidation, biological systems, adsorption, coagulation, and combined processes. Chemical precipitation, membrane filtration, and adsorption have high removal efficiencies that can reach more than 90% for different produced water components. The most effective method among these methods is adsorption using different adsorbents media. In this review, date-pits activated carbons, microemulsions-modified date pits, and cellulose nanocrystals as low-cost adsorbents were thoroughly reviewed and discussed. Moreover, the potential of using biological treatments in the removal of various pollutants from produced water such as conventional activated sludge, sequential batch reactor, and fixed-film biological aerated filter reactors were systematically discussed. Generally, produced water can be utilized in various fields including habitat and wildlife, agricultural and irrigation sector, energy sector, fire control, industrial use also power regeneration. The degree of treatment will depend on the application that produced water is being reused in. For instance, to use produced water in oil and gas industries, water will require minimal treatment while for agricultural and drinking purposes high treatment level will be required. It can also be concluded that one specific technique cannot be recommended that will meet all requirements including environmental, reuse, and recycling for sustainable energy. This is because of various dominant factors including the type of field, platform type, chemical composition, geological location, and chemical composition of the production chemicals. [Display omitted] • Adsorptive batch and biological treatments of produced water (PW) were discussed. • PW responsible for the largest contribution of waste stream volume. • PW characterizations are crucial for the optimal selection of treatment methods. • The development of treatment options for produced water was reviewed. • The degree of PW treatment depends on the application that PW is being reused in. [ABSTRACT FROM AUTHOR]

This study examines which management methods are the most recent and advanced in managing rejected brine generated from desalination plants. It also provides up-to-date information regarding the most adequate technologies that generate a minimum quantity of rejected brine via the use of minimization techniques and analyzes the method of direct disposal that has lately received noticeable improvements. It further discusses the reuse of discarded brine to recover valuable goods and sequestration of carbon dioxide. Sustainability is an important parameter that needs consideration to achieve uninterrupted operation of the discarded brine management to achieve the least environmental, social, and economic aftermath. To properly deal with any environmental issues related to brine disposal, different methods are implemented so that, in the end, higher water recovery is achievable from the desalination processes, namely brine minimization and rejection technologies (pressure retarded osmosis, microbial desalination cell technology), membrane-based technologies (vibratory shear enhanced processing, forward osmosis, electrodialysis, electrodialysis reverse, and electrodialysis metathesis, pervaporation method, thermal-based technologies (wind-aided intensified evaporation, brine concentrators, ohmic evaporator, membrane distillation, multi-stage flash distillation. This review also critically examined the two conventional approaches commonly used in life cycle assessment (LCA), when evaluating the ecotoxic effect of discarded brine. It intends to discuss the currently available methods and propose an improved method for evaluating the toxicity potential of brine on the aquatic ecosystem originated from seawater desalination plants. The Group-by-Group method takes into consideration the demerits of the two methods of the traditional method of LCA or chemical-specific approach as it provides a more holistic coverage for complicated brine to be disposed of. Recently, attention has been focused on recovering valuable metals from the discharged concentrated brine waste. Certainly, attaining marketable products from the discharged concentrated brine would offer an economic benefit and reducing the whole desalination costs. Ion imprinting polymers have potential applications in metal recovery from brine. Finding selective, more efficient, and less expensive imprinted polymers for extraction/pre-concentration of valuable ions is a vital and challenging task. Lastly, the brine should be seen as a resource and not as a waste to attain sustainability in its management approaches. Hybrid processes would be highly recommended to get the absolute transformation of the discarded brine from desalination processes to more valuable constituents. [Display omitted] • Brine is best managed when reducing its volume to the bare and accepted levels. • Brine is considered as a resource to achieve sustainability in water management. • All the emerging technologies are suitable for minimizing the brine volume. • The "group-by-group" approach can evaluate the ecotoxic effect of discarded brine. • Ion imprinting polymers have potential applications in metal recovery from brine. [ABSTRACT FROM AUTHOR]