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In this study, fourteen coffee samples were collected from local markets in Doha, Qatar according to different variables i.e. packed or unpacked, beans or powder, roasted or raw bean samples. The coffee samples were subjected to both microbiological and chromatographical analyses. The microbiological isolation was achieved using direct plating of the coffee on malt agar extract and potato dextrose agar plates. The chromatographical analytical method was conducted using ultra-high-performance liquid chromatography-fluorescence detector (UHPLC-FLD) to quantify the contamination of four classes of aflatoxins (B1, B2, G1, and G2). In the UHPLC-FLD validation process, no interfering peaks were present and the aflatoxins G1, B1, G2, and B2 were well separated. The R2 or coefficient of determination of the calibration plots for all compounds was ≥ 0.995. The limit of quantitation for all compounds was 2 μg/kg. The precision or the relative standard deviation calculated for six replicates of samples spiked at 2 μg/kg were less than 20%, and the limit of detection was 0.17 μg/kg, 0.14 μg/kg, 0.12 μg/kg and 0.09 μg/kg for Aflatoxins G1, Aflatoxins B1, Aflatoxins G2, and Aflatoxins B2, respectively. The average recovery calculated for six replicates of samples spiked at 2 μg/kg was from 74.5–80%. The results for the chromatographical part showed that there was no contamination of aflatoxin in most of the coffee samples collected. Only two samples exhibited low concentrations of aflatoxin G, which are sample A (4.27 × 10−1 μg/kg) and sample O (1.99 × 10−2 μg/kg). Direct plating showed growth of microorganisms, such as Aspergillus niger, Mucor sp., Bacillus sp., Fusarium sp., and two yeast species. Although some of the isolated species have the potential to produce mycotoxins in coffee, they might be in the spore phase in the coffee samples and did not germinate. [ABSTRACT FROM AUTHOR]

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 paper, commercially available graphene oxide (GO) was used as nanomaterials to modify polyamide reverse osmosis (RO) membrane surface. After functionalization, the membrane surface properties were improved as the water contact angle was reduced from 41.7 ± 4.5⁰ to 26.9 ± 0.9⁰ demonstrating improvement in hydrophilic properties besides decreasing membrane surface roughness. Membrane scaling tests were done in the presence of CaSO 4 solution at 20 mM concentration as feedwater showed that the modified membranes (GO@RO) had superior anti-scaling properties. Results indicated that the permeate flux was reduced by only 15% at the end of the scaling experiment as opposed to the bared RO membrane which faced up to 22% decline in flux. The results of scanning electron microscopy, Fourier transform infrared, and X-ray diffraction confirmed that the bared RO membrane was extensively scaled by the CaSO 4 precipitates. The results of antibacterial tests showed that GO functionalization caused an inhibition of bacterial growth by 81.7% as compared to the unmodified RO membrane. Moreover, experiments were also performed to investigate microbially induced calcium sulfate precipitation on membranes. Overall, it was found that GO functionalization not only reduces biofouling but can also inhibit mineral scaling and microbially induced mineral formation. Image 1 [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]

Abstract Seawater reverse osmosis (SWRO) is a commonly used desalination technique owing to its lesser environmental and economic impacts as compared to thermal desalination techniques. Antiscalants are used in SWRO to reduce membrane scaling caused by the supersaturation of salts present in feed water. However, to remain effective in reducing membrane scaling, antiscalants should be highly stable and resistant to biological degradation by seawater microorganisms. In this research, several bacteria from Qatar's seawater were isolated and screened for their ability to use antiscalants as a carbon and energy source. The biodiversity of antiscalant degrading seawater bacteria was demonstrated through combining the techniques of MALDI-TOF MS and principle component analysis. It was found that the bacteria isolated from Qatar's seawater such as H. aquamarina, H. elongata, P. fragi, P. stutzeri and others can degrade antiscalants and use them as a carbon and energy source. It was observed that the growth rates varied based on the type of antiscalant and the bacteria used. Among the tested strains, H. aquamarina, which is also known for its potential to cause biofouling, demonstrated the highest growth rates in antiscalants media. Thus, it was concluded that there is wide variety of bacteria in Qatar's seawater that can biodegrade the antiscalants; reducing their efficiency to combat membrane scaling. Since, these antiscalants will be used as a source of carbon and energy, microbial growth will increase resulting in enhanced membrane biofouling in SWRO. Graphical abstract Unlabelled Image Highlights • Antiscalants are commonly used to reduce scaling in seawater reverse osmosis. • The antiscalants are prone to enhance membrane biofouling. • There is a biodiversity of seawater bacteria that can biodegrade antiscalants. • Bacterial biodiversity can be explored through combining MALDI-TOF MS with PCA. • The specific growth rates vary with the type of bacteria and antiscalants. [ABSTRACT FROM AUTHOR]

We have shown that Bacillus cereus is dominating the bacterial population at three polluted oil-industry sites where weather and soil conditions are extreme in terms of temperature, UV-radiation and salinity. A minor part of the bacterial population includes a strain of Bacillus sonorensis and Pseudomonas stuztzeri . Six bacterial isolates were characterized by MALDI-TOF mass spectrometry. The identity of Bacillus sonorensis was also confirmed by ribotyping using molecular techniques. The extreme conditions result in the limited bacterial diversity at the present sites. Our results indicate that the bacteria have sustained because of their ability to degrade low, medium and high molecular weight hydrocarbons in diesel which were removed by up to 89%, 61% and 92%, respectively by Bacillus sonorensis . Bacillus cereus isolates were less effective, but all showed high activity on high molecular weight hydrocarbons. The study is based on growth tolerance to high diesel toxicity and removal of the three ranges of hydrocarbons. Each isolate showed higher hydrocarbon removal efficiencies when applied separately in biopiles in fresh soil compared to weathered soil. Almost 88% and 25% of the diesel range organics and 23% and 83% of the polyaromatic hydrocarbons were removed from the weathered soil versus the clean, respectively, by Bacillus sonorensis . Such efficiencies were obtained with growth stimulation by addition of nitrogen and phosphorus sources and with Tween-80 as a surfactant. The results are key in an application context, since it is clear that overcoming the recalcitrance of weathered hydrocarbon contaminations to biodegradation is a central issue in for example the Arabian Gulf. Moreover the results emphasize that bioaugmentation/biostimulation with bacteria originally adapted to the site conditions is the way forward since endogenous or exogenous hydrocarbon-degrading bacteria generally are not appropriate for applications that involve weathered hydrocarbon spills. [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]

Polymaleic acid was tested for its ability to control inorganic fouling in reverse osmosis (RO) system for the first time as a membrane surface modifier. Using the design of experiments (DoE) based on the response surface methodological (RSM) approach, the effect of polymaleic acid concentration and microwave radiation time duration was studied on the membrane permeation properties. Considering the objective of achieving maximum water permeance and salt rejection properties, the conditions of polymerization were optimized using RSM and experimentally validated in the lab. At the optimum conditions of 10 mg·L−1 polymaleic acid, and 27 s radiation time, the pure water permeance and salt rejection were 3.05 L·m−2·h−1·bar−1, and 97.8 %, respectively. The optimized membrane was characterized through microscopic and spectroscopic techniques. When tested for its performance under inorganic fouling conditions, the modified membrane demonstrated a negligible decline in permeate flux for 6 h, and no formation of calcium sulfate precipitates on the membrane surface. This research aims to promote the development, optimization, and application of dual-functional RO membranes that can control different types of membrane fouling. [Display omitted] • PMA-GO/RO functionalized membrane was tested for its ability to control inorganic fouling. • The PMA concentration and microwave radiation time were studied on the membrane permeation. • It demonstrated a negligible decline in permeate flux, and no CaSO 4 precipitates on the membrane. • 0.10 wt% PMA concentration and 27 s of radiation time yielded 97.8 % salt rejection. [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]

• A novel tailored ion-imprinted polymer for recovery of Li+ and Sr2+ was prepared. • The brine sample showed a higher Li+ and Sr2+ concentration of 43.32 mg/L and 16.93 mg/L, respectively. • Q m was increased as the temperature rise from 714 mg Li+/g at 25 °C to 2500 mg Li+/g at 45 °C. • Li+ desorption results show that 94.03% − 94.71% of the ions were recovered. • The IIP efficiency to adsorb Li+ from brine was 84.68%, and 10% for Sr2+. This study aims to prepare ion-imprinted polymer (IIP) with the benefit of a metal-based sorbent, which is fabricated to selectively adsorb lithium (Li+) from aqueous solutions, and in an attempt to remove strontium (Sr2+). The adsorption processes were carried out at different pH values, initial concentrations, and temperatures, to optimize the experimental conditions, with the use of response surface methodology (RSM). The seawater reverse osmosis (SWRO) brine was physically and chemically characterized, and the physicochemical characterization of the prepared IIP before and after adsorption was also performed using different spectroscopic methods. The adsorption capacity for Li+ and Sr2+ from SWRO brine was evaluated, and the reusability of IIP was investigated using adsorption–desorption cycles. The results showed that the IIP was efficient to remove Li+ but not Sr2+, and it follows Freundlich adsorption isotherms models. The analysis revealed a significant concentration of minerals in the brine sample It also revealed a low concentration of trace metals, like Ba (0.16 mg/L), Zn (0.845 mg/L), Fe (1.31 mg/L), Cu (1.165 mg/L), Pb (1.505 mg/L), and V (3.88 mg/L), except Li and Sr which shows a higher concentration of 43.32 mg/L and 16.93 mg/L respectively. pH 10 was selected to be the optimum pH for the adsorption isotherm experiments, as it was the highest efficient pH to adsorb Li+ and Sr2+. The thermodynamics study revealed that the adsorption of Li+ on the IIP favored exothermic conditions. It was noticed that the maximum adsorption capacity (Q m) was increased as the temperature rise from 714.3 mg/g at 25 °C to 2500 mg/g at 45 °C. The Li+ desorption results show that 94.03% − 94.71% of the ions were recovered, while the Sr2+ desorption results show that 96.35% − 96.56% of the ions were recovered. The efficiency of IIP to adsorb lithium and strontium from brine shows that the adsorption removal% of Li+ was between 84.21% and 84.68%, while the adsorption removal% of Sr2+ was between 3.83% and 10%. The cost analysis for IIP preparation was 2 USD/g. [ABSTRACT FROM AUTHOR]

The spent fluorescent lamps (SFLs) are being classified as a hazardous waste due to having mercury as one of its main components. Mercury is considered the second most toxic heavy metal (arsenic is the first) with harmful effects on animal nervous system as it causes different neurological disorders. In this research, the mercury from phosphor powder was leached, then bioremediated using bacterial strains isolated from Qatari environment. Leaching of mercury was carried out with nitric and hydrochloric acid solutions using two approaches: leaching at ambient conditions and microwave-assisted leaching. The results obtained from this research showed that microwave-assisted leaching method was significantly better in leaching mercury than the acid leaching where the mercury leaching efficiency reached 76.4%. For mercury bio-uptake, twenty bacterial strains (previously isolated and purified from petroleum oil contaminated soils) were sub-cultured on Luria Bertani (LB) plates with mercury chloride to check the bacterial tolerance to mercury. Seven of these twenty strains showed a degree of tolerance to mercury. The bio-uptake capacities of the promising strains were investigated using the mercury leached from the fluorescent lamps. Three of the strains ( Enterobacter helveticus , Citrobacter amalonaticus , and Cronobacter muytjensii ) showed bio-uptake efficiency ranged from 28.8% to 63.6%. [ABSTRACT FROM AUTHOR]

Commercial diesel is often loaded with organosulphur compounds including hard-to-remove dibenzothiophene DBT and other derivatives. Following uncommon and simple procedure, dibenzothiophene was selectively removed upon diesel acidification by acetic acid prior to activated carbon adsorption. Initially, competitive adsorption tests from synthetic fuel proved that dibenzothiophene is preferentially removed over di/tri and tetra-aromatic hydrocarbons upon fuel acidification by 5% ( by vol .) acetic acid. The efficacy of the proposed method was further validated by removing dibenzothiophene from commercial diesel containing 2578 (±15) mg kg −1 . The removal of DBT from complex diesel has increased from 27% to 55% upon acidification by 5% acetic acid. Acidity value of the treated diesel is within the regulated limit giving more chance for the new procedure for practical applications. [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. Currently, the total sulphur content in Jordanian diesel fuel is 12000ppmw (1.2%, wt/wt), but Jordanian government has recently introduced new restrictions that will reduce this level gradually to internationally acceptable levels. The zeolitic tuff (ZT), from Tlul Al-Shahba region, was characterised using various analytical techniques. It was found that the Freundlich model fitted the adsorption isotherms more accurately than the Langmuir model; indicating that the ZT had a heterogeneous surface. The Langmuir adsorption capacity values for the three particle size ranges (100–200), (300–400), and (500–600) μm were 7.15, 6.32, and 5.52mg/g and the column capacities were 4.45, 2.57, and 1.92mg/g, respectively. The spent ZT was regenerated by washing with n-heptane with an efficiency of 81.5%. Two adsorption mechanisms were investigated. One is that the interaction of thiophene with the Brønsted site of the ZT through S atoms; the other is via C–S bond cleavage in thiophene-derived carbocations to form unsaturated fragments on the Brønsted acid sites. [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]

Abstract: The viscosity index (VI) and the base number (BN) of motor oils are the most important parameters to be measured in order to assess their performance and service time. Both parameters were simply obtained for virgin and recycled motor oil samples using multivariate calibration based on the FTIR data. Analysis showed that the PLS-1 has outperformed CLS and PCR for the oil parameters prediction. Five and four PLS-1 latent variables were found optimum to obtained the VI and the BN from the FTIR data; respectively. With high accuracy (99–102%) and precision (3–11%), the BN could be determined over the range 4.57–16.45mgKOHg−1 and the VI over the range 96–153. The outputs of the PLS-1 were found comparable to those obtained by the expensive and time-consuming ASTM methods. This developed method is highly recommended for quick monitoring of the motor oil quality parameters. [Copyright &y& Elsevier]

Abstract: A potential usefulness of raw date pits as an inexpensive solid adsorbent for methylene blue (MB), copper ion (Cu2+), and cadmium ion (Cd2+) has been demonstrated in this work. This work was conducted to provide fundamental information from the study of equilibrium adsorption isotherms and to investigate the adsorption mechanisms in the adsorption of MB, Cu2+, and Cd2+ onto raw date pits. The fit of two models, namely Langmuir and Freundlich models, to experimental data obtained from the adsorption isotherms was checked. The adsorption capacities of the raw date pits towards MB and both Cu2+ and Cd2+ ions obtained from Langmuir and Freundlich models were found to be 277.8, 35.9, and 39.5mgg−1, respectively. Surface functional groups on the raw date pits surface substantially influence the adsorption characteristics of MB, Cu2+, and Cd2+ onto the raw date pits. The Fourier transform infrared spectroscopy (FTIR) studies show clear differences in both absorbances and shapes of the bands and in their locations before and after solute adsorption. Two mechanisms were observed for MB adsorption, hydrogen bonding and electrostatic attraction, while other mechanisms were observed for Cu2+ and Cd2+. For Cu2+, binding two cellulose/lignin units together is the predominant mechanism. For Cd2+, the predominant mechanism is by binding itself using two hydroxyl groups in the cellulose/lignin unit. [Copyright &y& Elsevier]

Abstract: The precise determination of the heat of combustion is of great importance for trading automotive diesel. The net heat of combustion (NHC) of fuel is related to the hydrogen elemental composition of fuel as obtained by elemental analysis. Heat of combustion expressed as gross heat of combustion (GHC) and net heat of combustion (NHC) have been predicted from data obtained by proximate analysis (density, ash, water and sulphur content) (ASTM D4868). GHC was obtained using bomb calorimetry (ASTM D240). The results of ASTM D4868 and ASTM D240 were found in good agreement. GHC and NHC fall within the relatively narrow range 45.24–46.08 and 41.91–43.27MJ/kg, respectively. GHCs of tested diesel samples are, on average, about 7% greater than NHCs. The present paper also present a simple analytical method for determination of hydrogen content, GHC, and NHC of automotive diesel fuel using FTIR spectroscopy and partial-least squares calibration (PLS-1). PLS-1 had a high prediction power for prediction of hydrogen from FTIR spectra of diesel samples. The spectral ranges used in calibration were 400–670 and 2846–2970cm−1. On the other hand, classical least squares calibration (CLS) was found invalid for determination of hydrogen content in diesel. The results obtained by the proposed analytical method were almost to those obtained by ASTM D4868 and ASTM D240. PLS-1 method, offers a simple and reliable analytical method for quantification of hydrogen content in diesel samples without running expensive analysis like those carried out using carbon, hydrogen, and nitrogen (CHN) instruments. [Copyright &y& Elsevier]

Abstract: The application of solid-phase extraction with multivariate calibration for simultaneous determination of three toxic pesticides in tap and reservoir waters was presented. The proposed analytical method was used for the determination of atrazine, methidathion, and propoxur in complex water samples without the need for chromatographic separation. Among the applied multivariate calibration methods, partial least squares (PLS-1) method was found the most effective for pesticides quantification. Multiwalled carbon nanotubes (MWCNTs) adsorbent showed a perfect extraction/preconcentration of pesticides present at trace levels. The experimental factors that affect pesticides extraction by MWCNTs adsorbent such as sample volume, eluent volume, solution pH, and extraction flow rate were studied and optimized. The figures of merit of the proposed method were: limits of detection 3, 2, and 3μgl−1 and linear ranges 5–30, 3–60, and 5–40μgl−1 for atrazine, methidathion, and propoxur, respectively. A good precision was reported for the method, R.S.D. values were always less than 5.0%. Satisfactory results were reported for simultaneous determination of trace levels of pesticides in complex matrices. In tap water, the percent recoveries for pesticides were extended from 95 to 104% and R.S.D. from 1 to 3%, while lower recoveries were observed in reservoir water: 84–93% (R.S.D.: 1–3). Although the pesticides can be accurately quantified by SPE and liquid chromatography, SPE–PLS-1 method was found simpler and operated at lower running costs. [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]

The effect of initial concentration, particle size, mass of the adsorbent, pH and agitation speed on adsorption behaviour of methylene blue (MB) onto Jordanian diatomite has been investigated. The maximum adsorption capacity, q, increased from 75 to 105mg/g when pH of the dye solution increased from 4 to 11. It is clear that the ionisable charge sites on the diatomite surface increased when pH increased from 4 to 11. When the solution pH was above the pHZPC, the diatomite surface had a negative charge, while at low pH (pH<5.4) it has a positive charge. The adsorption capacity increased from 88.6 to 143.3mg/g as the initial MB concentrations increased from 89.6 to 225.2mg/dm3. The experimental results were also applied to the pseudo-first and -second order kinetic models. It is noticed that the whole experimental data of MB adsorption onto diatomite did not follow the pseudo-first order model and had low correlation coefficients (R 2 <0.3). The calculated adsorption capacity, q e,cal , values obtained from pseudo-first order kinetic model did not give acceptable values, q e,exp. The maximum uptake capacity seems to be independent of the particle size of the diatomite when the particle size distribution is less than 250–500μm. While at larger particle size 250–500μm, the maximum uptake capacity was dependent on the particle size. It would imply that the MB adsorption is limited by the external surface and that intraparticle diffusion is reduced. The effect of the agitation speeds on the removal of MB from aqueous solution using the diatomite is quite low. The MB removal increased from 43 to 100% when mass of the diatomite increased from 0.3 to 1.7g. [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]

Abstract: In this paper, an attempt has been made to develop a feasible procedure for the prediction of quality parameters of motor gasoline and to discriminate between the different adulterated motor gasoline samples using density values, distillation temperatures and Fourier transform infrared (FTIR) analyses along with multivariate calibrations without the need for using chromatographic separation or other expensive instruments such as an octane number analyser. Ten blend mixtures of regular and super motor gasoline were prepared in order to study density, distillation temperatures and FTIR spectra characteristics for each blend. Distillation temperatures for the pure and blend mixtures of regular and super motor gasoline at initial boiling point (IBP) to final boling point (FBP) at 5%Vol. interval were obtained. Accurate and complete distillation data on the uncontaminated fuel would be essential for comparison. Thirteen peaks of the absorbance at the wavenumbers: 434, 461, 484, 673, 694, 1030, 1086, 1217, 1231, 1460, 1497, 1606 and 3028cm−1 were chosen to perform the multivariate calibration. The results obtained were expected to be useful in determination and differentiation purposes, providing information on whether the density values, distillation temperatures and FTIR analyses along with multivariate method could be an appropriate feature for differentiating a particular pure motor gasoline sample from the others. The observed differences in the specific spectral bands are investigated and discussed. They have proven to be an effective combination in the pursuit of management''s differentiation goals. [Copyright &y& Elsevier]

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 polyamide reverse osmosis (RO) membrane was modified with graphene oxide (GO), followed by polymerization of acrylic acid (used as an antiscalant) for the reduction of both biofouling and mineral scaling. After functionalization, the water contact angle reduced from 41.7 ± 4.5° for unmodified RO membrane to 24.4 ± 1.3° for the modified RO membranes, which showed that membrane hydrophilicity was significantly enhanced, in addition to the improvement in surface smoothness. The modified membranes were tested for their anti-scaling and anti-biofouling characteristics. When the mineral scaling test was performed using CaSO 4 solution as feedwater, the permeate flux was reduced by only 3% as compared to the unmodified RO membrane which encountered up to 22% decline in flux by the end of the experiment. After the scaling test, the membrane surface was characterized by Scanning electron microscopy – energy-dispersive X-ray spectroscopy, Fourier transform infrared, and X-ray diffraction techniques. The results showed that the unmodified RO membrane was fully covered with gypsum precipitates. Whereas, the precipitates were detected only at the highly saturated zones of the water channel i.e. towards the exit of water flow. Additionally, the anti-bacterial test was performed through bacteriostasis rate determination, which showed that the modified membranes inhibited the growth of nearly 95% of the bacterial cells. Further experiments were also performed to investigate the inhibition of both scaling and biofouling by modified RO membranes. Thus, it was found that the polymer-modified GO coated RO membranes were able to diminish both gypsum scaling and biofilm formation demonstrating their potential to control different types of membrane fouling. Unlabelled Image • The reverse osmosis membrane was modified with graphene oxide and polyacrylic acid. • The surface smoothness and hydrophilicity of the modified membranes were improved. • The permeate flux was reduced by only 3% as compared to unmodified RO membrane. • The modified membranes inhibited the growth of nearly 97% of the bacterial cells. • The modified membranes were able to diminish both gypsum scaling and biofouling. [ABSTRACT FROM AUTHOR]

In this research, the interactions of seawater microorganisms with scalants (minerals like calcium sulfate) and antiscalants in the reverse osmosis (RO) systems were investigated. The interaction of seawater microorganisms with antiscalants was investigated by measuring the growth of bacteria in an antiscalant containing growth medium, which was added as a sole source of carbon and energy. Moreover, the interaction of microorganism with calcium sulfate (selected as a model scalant) was also investigated using scanning electron microscopy – energy dispersive x-ray spectroscopic technique. It was found that several Pseudomonas strains isolated from the marine water of Qatar are capable of using antiscalants as an energy or carbon source. It was noted that the growth curves of the strains vary with the type of the antiscalant studied. Furthermore, the results of microorganism-scalant interaction showed that the presence of bacteria induced/mediated precipitation of calcium sulfate on the RO membranes, whereas, no precipitation was noted on the control RO membranes (i.e. without bacteria) under the studied conditions. Therefore, the results of this research showed that the presence of microorganisms in seawater reverse osmosis not only causes biofouling but also enhances mineral scaling through biodegradation of antiscalants and precipitation of minerals (calcium sulfate). Unlabelled Image • Investigated the interaction of seawater microorganisms with scalants in RO • Investigated the interaction of seawater microorganisms with antiscalants in RO • Pseudomonas fragi and Pseudomonas stutzeri were isolated from Qatar's marine water. • Pseudomonas biodegraded antiscalants and utilize them as a source of energy/carbon. • The presence of bacteria induced precipitation of calcium sulfate on RO membrane. [ABSTRACT FROM AUTHOR]

• Adsorption data modelling is an essential way of predicting adsorption mechanisms. • It discusses the guidelines of using mono/multi-parametric isotherm models. • It establishes criteria for choosing the optimum isotherm model. • Ten multi-parameter isotherm models and their applications were reviewed. • Linear and nonlinear regression equations were used to determine best-fit model. Adsorption process is considered as one of the most used separation and purification processes, in which adsorption occurs by the formation of the physical or chemical bonds between a porous solid medium and a mixture of liquid or gas multi-component fluid. By taking into consideration the equilibrium data and the adsorption properties of both the adsorbent and the adsorbate, adsorption isotherm models can describe the interaction mechanisms between the adsorbent and the adsorbate at constant temperature. Therefore, understanding modelling of the equilibrium data is a very essential way of predicting the adsorption mechanisms of various adsorption systems. Furthermore, adsorption isotherms in batch experiments can be used for the determination of the solid-water distribution coefficient (K id). This review paper discusses the guidelines of using mono/multi-parametric isotherm models with different applications. The aim of this paper is to establish criteria for choosing the optimum isotherm model through a critical review of different adsorption models and the use of various mathematically error functions such as linear regression analysis, nonlinear regression analysis, and error functions for adsorption data optimization. In this paper, 15 mono-parametric adsorption isotherm models having one, two, three, four and five parameters were investigated. In addition, 10 multi-parameter isotherm models were reviewed as well as addressing their applications. [ABSTRACT FROM AUTHOR]

• Few samples show Pb concentration above the limit set by WHO and FAO of 0.2 mg/kg. • Cd concentration was decreased with increasing the water acidity. • Temperatures and acid concentrations had more significant effects on Cd than Pb. • Cd levels were found to be higher in brown rice than white rice. In this research, effect of soaking time, acidity and temperature on the removal of lead and cadmium from rice was investigated. Different rice treatments were involved i.e. three soaking times (0, 15, and 30 min), three temperatures (20, 25, and 30 °C) and four concentrations of glacial acetic acid (0.5%, 1%, 2%, and 3%). Results showed that few samples have shown lead concentrations above the maximum limit set by the World Health Organization (WHO) and the UN Food and Agriculture Organization (FAO) of 0.2 mg/kg, whereas, all cadmium concentrations were below the limit of 0.4 mg/kg. A decrease in lead and cadmium concentrations were observed with increasing time of soaking. Lead had the lowest concentration at 20 °C, while cadmium had the lowest concentration at 30 °C. Cadmium concentration decreased with increasing water acidity, while the lead concentration reached the lowest concentration with 1% acidity. [ABSTRACT FROM AUTHOR]

• Membrane fouling is major hurdle for the widespread use of membrane technology. • Increase in temperature can affect CaSO 4 scaling intensity, and morphology. • At higher temperature, crystal morphology changes from rod shape to rosette structures. • Using PCA, membrane's permeate flux can be differentiated at different conditions. • FTIR results showed the involvement of OH, COOH and NH 2 groups in membrane scaling. Membrane fouling is one of the major hurdles in widespread use of seawater reverse osmosis (SWRO) in desalination industry. There are various factors that affect the inorganic fouling or scaling of Reverse osmosis (RO) membranes. In this research, the effect of temperature on scaling of RO and Graphene oxide (GO) coated RO membrane by calcium sulfate was investigated. It was found that the increase in temperature enhanced the membrane scaling which was evident by the severe flux decline over time leading to increase in mass of crystals precipitated (M t) and thickness of the scale layer. There was strong positive correlation (R2 ≥ 0.97) noted between M t and the temperature. The results of SEM-EDX and XRD confirmed that the crystals formed under the experimental conditions are gypsum. Results of this research showed that there was no significant difference in terms of crystal morphology, scaling intensity and mechanism after modifying RO membrane with GO. It was noted that the morphology of the crystals varied from rod shaped to rosette structures under the influence of temperature. Furthermore, the results of FTIR helped to understand the mechanism of interaction between the membranes and the gypsum. The hydrophilicity of the scaled membrane was also measured to investigate the changes in the properties of the membrane after scaling. [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]

Summary: In this study, styrene‐butadiene‐styrene (SBS) was used to develop a novel functionalized electrospun membrane for the effective treatment of heavy metals in direct contact membrane distillation (DCMD) applications. Functionalization was achieved by the addition (doping) of the super hydrophobic Al2O3 nanoparticles (Al NPs) within the matrix of the membrane during electrospinning. Neat (pristine nondoped) and doped SBS membranes were tested. The performance of the SBS membranes were also compared with fabricated polyvinylidene fluoride membranes with and without doping with Al NPs. The membrane characteristics were tested via Fourier transform infrared, scanning electron microscopy, pore size, and porosity investigations. The wettability of the membranes was investigated with respect to the liquid entry pressure (LEP) and contact angle. The performance of the membranes was tested in a DCMD setting for its ability to treat water containing salt (NaCl) and heavy metals (Cr (VI), Cd, Pb) in various concentration in a single and multicomponent systems. The SBS member exhibited excellent hydrophobicity characteristics such as a high LEP (16.87 psi) and contact angle (141° ± 2°). It also had superior permeate flux rate compared to the other prepared membranes (54.4 LMH). The addition of the Al2O3 nanoparticles enhance the performance of the membranes substantially. Slight decline in the flux was observed after 14 hours of continuous operating time that could be attributed to agglomeration, adsorption, or temperature polarization effects. The SBS AL NPs membranes also demonstrated excellent flux for saline solutions of varied concentrations with 99% salt rejection. [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]