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A novel catalyst was synthesised in a way that it could be applied in simultaneous adsorption and heterogeneous Fenton processes. The granulated Fe3O4/CuBDC/Cellulose nanocomposites were synthesised with a novel in-situ granulation method in a rotary autoclave reactor, and they were efficient in the removal of a detrimental trisazo dye, direct blue 71 (DB71). The catalysts were characterised by various analyses. In order to fulfill the expectation from the catalysts traits, many parameters were evaluated meticulously such as the effect of modification of Fe3O4 nanoparticles, the ratio of Fe3O4 to CuBDC in the nanocomposite, the stability of the catalyst, and diverse catalyst characterisations (SEM, EDX, FTIR, XRD, BET, XPS). The rotating speed of the autoclave was optimised by carrying out computational fluid dynamics (CFD) simulations; 60 rpm rotating speed was selected among the other ones to achieve catalysts that were more homogeneous. Moreover, the dye elimination process was conducted in a pilot fluidised bed reactor. The impacts of three diverse parameters on the removal efficiency were assessed by response surface method (RSM) to optimise them, 96.85% dye removal was achieved in a 30-min process (the initial DB71 concentration = 10 mg/L, the H2O2 concentration = 8.55 mM, and the catalyst dosage = 7.12 g/L). The study of the dye elimination mechanism and thermodynamics of the process indicated endothermic, spontaneous, favourable, and physical adsorption of DB71 on the catalysts. Reutilisation of granulated catalysts at least for ten treatment cycles without regeneration process incorporating high and stable degradation efficiency (11% performance reduction), exhibited the exceeding performance of the highly durable well-designed catalysts in the simultaneous adsorption and heterogeneous Fenton processes. [ABSTRACT FROM AUTHOR]

Antibiotic resistance, along with its dynamics in different environments, has attracted increasing attention because of the potential for resistance gene transfer into human pathogens. Therefore, several researchers have focused on combating the increasing prevalence of antibiotic resistance genes (ARGs) in diverse environments, using various carbon-based amendments to resolve issues regarding emerging contaminants. However, information on systematic knowledge regarding carbon-based material performance and mechanisms for alleviating ARGs remains lacking. To this end, we summarize carbon-based materials that are used as additives, amendments, adsorbents, and other functional materials in compost, soil, and water environments. The underlying mechanisms of alleviating ARG pollution using carbon-based materials are mainly related to 1) environmental factor improvement, 2) microbial community structure alteration, 3) chemical contaminant-caused co-selective pressure reduction, 4) mobile genetic element (mediating horizontal gene transfer processes) reduction, and 5) direct adsorption and/or damage to extracellular DNA. This review aimed to enrich our understanding of the functional roles of carbon-based materials and provide a basis for management strategy development to mitigate ARG pollution. [ABSTRACT FROM AUTHOR]

Molecular modelling and simulation were used to examine the efficacy of iron nanoparticles (Fe3O4–NPs) in removing amoxicillin (AMX) from aqueous media and determine the optimal conditions. Fe3O4–NPs were initially ascertained using scanning electron microscopy, and Fourier transform infrared spectroscopy. The molecular optimisation modelling via DFT confirmed AMX molecule has chemical potential (–3.59), and electrophilicity index (2.14). The results established that a small chemical hardness = 3.0 eV and molecular energy gap of 6.01 eV, which makes it reactive. The molecule of the antibiotics could interact and be absorbed by the lactase enzyme. The parameters: pH (3–7), time (15–80 min), Fe3O4–NPs dosage (0.1–1.0 g/L), and antibiotic concentration (10–100 mg/L) were studied. The impact of optimum variables pH3, and dosage (0.5 g/L) for adsorption of AMX molecules onto coated Fe3O4–NPs translated to 98% efficiency at 60 mg/l of AMX and 60 min. The adsorption data fitted the Langmuir (R2: 0.9245) with minimal error metrics RMSE ≤ 1.2 when compared to the Freundlich isotherm R2 (0.88) and intraparticle diffusion model R2 (0.58). The maximum adsorption capacity of AMX to Fe3O4–NPs corresponds to 6.47 mg/g with a corresponding adsorption constant of 2.8. Furthermore, AMX adsorption onto Fe3O4–NPs followed pseudo-second-order at R2 (0.9999), with an adsorption constant (k = 3.6 × 10−2g/mg.min). [ABSTRACT FROM AUTHOR]

Colloidal gas aphrons (CGAs) are highly stable, spherical, micrometer-sized bubbles encapsulated by surfactant multilayers. They have several intriguing properties, including: high stability, large interfacial area, and the ability to maintain the same charge as their parent molecules. The physical properties of CGAs make them ideal for biotechnological applications such as the recovery of a variety of: biomolecules, particularly proteins, yeast, enzymes, and microalgae. In this review, the bio-application of CGAs for the recovery of natural components is presented, as well as: experimental results, technical challenges, and critical research directions for the future. Experimental results from the literature showed that the recovery of biomolecules was mainly determined by electrostatic or hydrophobic interactions between polyphenols and proteins (lysozyme, β-casein, β-lactoglobulin, etc.), yeast, biological molecules (gallic acid and norbixin), and microalgae with CGAs. Knowledge transfer is essential for commercializing CGA-based bio-product recovery, which will be recognized as a viable technology in the future. [ABSTRACT FROM AUTHOR]

The adsorption of Acid orange 7 (AO7) by Polypyrrole/nanosilica composite (PPN/SiO2) was studied and various parameters have been investigated, more than 99.4% of the adsorption efficiency was obtained under the optimal conditions (PPN/SiO2 mass = 1 g/L, contact time = 90 min, Initial AO7 concentration = 10 mg/L, shaking speed = 200 rpm and temperature = 328 K and pH = 3).PPN/SiO2specifications were determined using FTIR, XRD, TGA, pHzpc,TEM and SEM analysis. The kinetic data were fitted by the pseudo-second-order kinetic; the rate constant K increased when temperature increased indicating the adsorption was endothermic in nature. The studies related to the adsorption mechanism illuminated that the AO7 adsorption process was complex and obeyed both surface adsorption and particle diffusion. Moreover, based on the results, the adsorption happens through film diffusion at low concentrations while the particle diffusion is the rate-determining step at higher concentration. The isotherm equations showed that the equilibrium data followed more than the Langmuir isotherm with a maximum adsorption capacity of 181.4 mg/g. The thermodynamic parameters were calculated, and their negative value of ΔG° and positive value of ΔS° and ΔH° showed that the adsorption was spontaneous and endothermic. [ABSTRACT FROM AUTHOR]

Halide double perovskites are the best alternative to Pb-halide perovskites. These materials play an important role in renewable energy generation. Therefore, we explore the physical properties of K2AgAsX6 (X = Cl, Br) double halide perovskites using full potential linearized augmented plane wave method. The structural parameters are calculated by optimization and analytical schemes. The negative values of formation energy confirm the thermodynamic stability, while Goldsmith's tolerance factor guarantees the structural stability of both the double perovskites. The bandgaps of K2AgAsCl6 and K2AgAsBr6 are calculated as 2.10 and 1.48 eV, respectively by modified Becke and Johnson potential. Optical properties are examined in terms of the dielectric function, refractive index and absorption coefficients. The thermoelectric properties are calculated in terms of the electronic and thermal conductivities, Seebeck coefficients, power factor and figure of merit. Our study suggests the K2AgAsX6 perovskites for energy-related applications. [ABSTRACT FROM AUTHOR]

Cancer is one of the most lethal diseases, and limited available treatment options contribute to its high mortality rate. Exosomes are considered membrane-bound nanovesicles that include different molecules such as lipids, proteins, and nucleic acids. Virtually most cells could release exosomes via exocytosis in physiological and pathological conditions. Tumour-derived exosomes (TDEs) play essential roles in tumorigenesis, proliferation, progression, metastasis, immune escape, and chemoresistance by transferring functional biological cargos, triggering different autocrine, and paracrine signalling cascades. Due to their antigen-presenting properties, exosomes are widely used as biomarkers and drug carriers and have a prominent role in cancer immunotherapy. They offer various advantages in carrier systems (e.g. in chemotherapy, siRNA, and miRNA), delivery of diagnostic agents owing to their stability, loading of hydrophobic and hydrophilic agents, and drug targeting. Novel exosomes-based carriers can be generated as intelligent systems using various sources and crosslinking chemistry extracellular vesicles (EVs). Exosomes studded with targeting ligands, including peptides, can impart in targeted delivery of cargos to tumour cells. In this review, we comprehensively summarised the important role of tumour-derived exosomes in dictating cancer pathogenesis and resistance to therapy. We have therefore, investigated in further detail the pivotal role of tumour-derived exosomes in targeting various cancer cells and their applications, and prospects in cancer therapy and diagnosis. Additionally, we have implicated the potential utility and significance of tumour exosomes-based nanoparticles as an efficient and novel therapeutic carrier and their applications in treating advanced cancers. [ABSTRACT FROM AUTHOR]

In this research, a low-cost and locally available by-product, pumpkin shell, was used to prepare pumpkin char (PC), and activated carbon using ZnCl2 (PCZC), H3PO4 (PCPA) activation agents and Pb (II) ion removal properties from the aqueous solution were investigated. The adsorption process was studied as a function of solution pH (2–7), initial concentration of Pb (II) (10–50 mg/L), volume of solution (10–200 mL), adsorbent dosage (0.005–0.04 g), contact time (5–120 min) and temperature of solution (308–333 K). The obtained results of experiments show that with the increase in the value of pH, the percentage Pb (II) ion removal increases by 87.59, 88.83 and 94.67% for PC, PCZC and PCPA, respectively. According to these results, the optimised value of pH for PC, PCZC and PCPA adsorbents is 5, 6 and 5, respectively. Moreover, the optimised adsorbent dosages for PC, PCZC and PCPA are 0.015, 0.01 and 0.01 g, respectively. The SEM images of PC, PCZC and PCPA after Pb (II) adsorption show that Pb (II) ions covered the surface of adsorbents in the form of nanoparticles. The experimental data were analysed using two parameter isotherm models namely: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich. The obtained results of the Langmuir model showed that the maximum adsorption capacity of PC, PCZC and PCPA adsorbents was 46.948, 140.845 and 117.647 mg/g at 333 K, respectively. Adsorption of Pb (II) ion onto these adsorbents followed the Langmuir isotherm and PSO kinetic model. In addition, the kinetics data were investigated by the pseudo-first-order (PFO), pseudo-second-order (PSO) and intra-particle diffusion (IPD) models. [ABSTRACT FROM AUTHOR]

Pure anatase TiO2 nanoparticles and two kinds of TiO2–SnO2 nanocomposite with different amounts of SnO2 nanoparticles (A-S (1-1) and A-S (1-2)) are synthesised. The X-ray diffraction (XRD) pattern is used for the characterisation of the synthesised samples. The XRD results confirmed that synthesised TiO2 nanoparticles have an anatase structure and SnO2 nanoparticles possess a tetragonal structure. The results of TEM reveal that the particle size of the TiO2 nanoparticles is less than 30 nm. Meanwhile, the SnO2 nanoparticle is successfully introduced onto the outer surface of TiO2 nanoparticles. The variation in the removal efficiency of methyl orange as an organic pollutant with UV irradiation time, weight fraction of synthesised photocatalysts and pH is investigated. The obtained results confirm that the removal efficiency of methyl orange increases in respect of the UV irradiation time and weight fraction. In addition, it is observed that the highest and lowest removal efficiencies occur at pH = 3 and pH = 11, respectively. Meanwhile, the results reveal that the removal efficiency of methyl orange is enhanced in respect of the SnO2 nanoparticles content in the synthesised nanocomposite. The analysis of variance investigation reveals that all the main factors have a significant effect on the removal efficiency of pollutant. Meanwhile, the proposed models can accurately predict the variation of the removal efficiency with studied parameters. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the quality index, functional groups changes, and antimicrobial activity of ozonized pomegranate seeds oil (OPSO). Results have shown that peroxide and acidity values were increased with ozonation times. The FT-IR and 1 H NMR analyses of oil samples have confirmed chain scission at C = C bonds of the fatty acid chains during ozonation and the formation of new carbonyl compounds such as aldehyde, 1,2,4-trioxolane. The ozonation reaction improves the antibacterial activity of non-ozonized PSO. These results make an open door to new applications of OPSO. [ABSTRACT FROM AUTHOR]

The main objective of this research is the development of innovative two-layer tubular ceramic membranes with improved separation properties, high mechanical and thermal stability using affordable and easily accessible raw materials. In this regard, firstly, the clay-based ceramic support membrane was fabricated by extrusion technique using kaolin, alumina and natural zeolite. Besides, changes in thermal properties, shrinkage, porosity and mechanical strength of the prepared sample were evaluated as a function of treating temperature to obtain the best membrane support. Subsequently, the cross-flow filtration technique was employed to coat the natural zeolite and activated carbon over the support membrane to prepare the two-layer microfiltration membranes of MF-Z and MF-C, respectively. Finally, the performance of ceramic support, MF-Z and MF-C membranes were assessed during oily wastewater treatment. The results revealed that MF-Z and MF-C membranes could remove oil from 1,000 to 90 mg/L and 1,000 to 13 mg/L, respectively, while the concentration of oil in the permeate flux of the ceramic support was around 190 mg/L. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the residues of pyrethroid and organophosphorus pesticide in flour and breads which were collected from local markets in Kermanshah province, Iran. Four different types of breads and two types of flour samples with high distribution were taken from market and their residues of pesticides were measured. A simple dispersive liquid–liquid microextraction (DLLME) method with solidification of floating organic drop was developed for the measurement. The health risk of these pesticides on adults and children health was assessed by target hazard quotient (THQ) using Monte Carlo simulation (MCS) method. About, 15% and 11.1% of total samples contained detectable levels of deltamethrin and malathion, respectively. None of the tested samples showed any permethrin residue. The results from all samples showed that none of the pesticides exceeded the maximum residue limits (MRLs). About 85% of pesticide residue detections were observed in tropical and mild weather area which is due to high consumption rate of insecticides in these areas. The percentile 95% of THQ is due to bread ingestion content of deltamethrin which was 0.033 and 0.070 for the adults and children, respectively, while this value for malathion was found to be, 0.015 and 0.030, respectively. In the adults and children for both deltamethrin and malathion, the percentile 95% of THQ value were lower than 1 (acceptable level). The non-carcinogenic health risk assessment indicated that bread consumers in Kermanshah province are not at a considerable risk because of deltamethrin and malathion. [ABSTRACT FROM AUTHOR]

A method has been developed for the determination of 24 elements (As, B, Ce, Co, Dy, Fe, K, La, Lu, Mg, Mn, Na, Nb, Nd, P, Pr, Rb, S, Sb, Si, Sm, Th, Ti, and U) in ore samples by pulsed direct current glow discharge time-of-flight mass spectrometry (PGD-TOF-MS). Sample treatment consisted of pressing the powdered samples into 10 mm diameter aluminum tablets. Quantification was performed using relative sensitivity factors with iron as the normalization element. PGD-TOFMS has low spectral interferences and low limits of detection and provides the quantification of the wide range of elements with a single method instead of a combination of several techniques. The limits of detection of the designed method were in the range 2-4 × 10−6 mass %, depending on the element. The designed procedure was validated by the analysis of standard reference materials. The obtained results showed adequate repeatability (6-9% relative standard deviation), demonstrating high efficiency of the glow discharge mass spectrometry for the direct analysis of geological samples. The designed method requires a minimal sample pretreatment and is applicable for the determination of wide range of elements of the periodic table (e.g., metals, nonmetals, and rare earth elements) in a single analytical procedure without sample dissolution with adequate accuracy, sensitivity, and repeatability. The designed approach may replace the complex techniques that are normally required for this task. [ABSTRACT FROM AUTHOR]

The removal of phenol sulfonic acid-syntan (PSAS) in terms of chemical oxygen demand (COD) was studied at different pH, ozone and initial PSAS concentrations and the optimum condition was found to be pH 7, ozone concentration of 5.2 × 10−3 mmol/L and initial PSAS concentration of 500 mg/L. The increase in BOD5/COD ratio confirmed the bio-treatability of ozonated PSAS effluent. The excitation-emission matrix intensity and Fourier transmission infra-red spectroscopy confirmed the generation of intermediate by-product during degradation of PSAS. The ozonation of PSAS was found to obey fast regime pseudo-first-order reaction with a rate constant of 3.7 × 10-9 mol−1 s−1. The mean oxidation state of carbon value between +2 and +3 confirmed that the ozonation of PSAS resulted in partial mineralization. [ABSTRACT FROM AUTHOR]

A campaign was conducted to assess the PM1 concentration and elemental composition on the platforms and adjacent outdoor areas of an underground subway station (Imam Khomeini) and a surface subway station (Sadeghiye) in Tehran from June 2014 to November 2014. The respective mean concentrations of PM1 on the platforms and in the outdoor areas of Imam Khomeini station were 42.04 and 30.92 µg/m3 and for Sadeghiye station 31.42 and 26.02 µg/m3. Statistical analyses demonstrated that the platforms of the Imam Khomeini and Sadeghiye stations were influenced by the adjacent ambient air of these stations (p < 0.05). PM1 was found to be highly enriched with Fe on the platforms of metro systems, which were more frequently encountered in the Imam Khomeini station than the Sadeghiye station as 41.06% and 37.73% of the total PM1 mass respectively. Minor elements, particularly Ba, Pb, Cr, Cu, Ni, Mn, Ti, V, and Zn, were elevated for the platform of Imam Khomeini and, to a lesser degree, the platform of Sadeghiye stations, which may be due to abrasion processes between rail tracks, wheels, and brake pads. [ABSTRACT FROM AUTHOR]

In the present study, the adsorption of sulfates of sodium sulfate (Na2SO4) and sodium lauryl sulfate (SLS) by calcium hydroxyapatite-modified microfibrillated cellulose was studied in the aqueous solution. The adsorbent was characterized using elemental analysis, Fourier transform infrared, scanning electron microscope and elemental analysis in order to gain the information on its structure and physico-chemical properties. The adsorption studies were conducted in batch mode. The effects of solution pH, contact time, the initial concentration of sulfate and the effect of competing anions were studied on the performance of synthesized adsorbent for sulfate removal. Adsorption kinetics indicated very fast adsorption rate for sulfate of both sources (Na2SO4 and SLS) and the adsorption process was well described by the pseudo-second-order kinetic model. Experimental maximum adsorption capacities were found to be 34.53 mg g-1for sulfates of SLS and 7.35 mg g-1 for sulfates of Na2SO4. The equilibrium data were described by the Langmuir, Sips, Freundlich, Toth and Redlich--Peterson isotherm models using five different error functions. [ABSTRACT FROM AUTHOR]

The concentration of 13 metals (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Pb, and Hg) and their associated health risk assessment was performed for two Himalayan lakes, urban Phewa and remote Gosainkunda, from Nepal. Water Quality Index (WQI), Metal Index (MI), Hazard Quotient (HQ), Hazard Index, and Cancer Risk were calculated in order to evaluate the water quality of these lakes. Correlation analysis revealed that Mn and Fe were derived from natural geological weathering processes and Pb, V, Cr, Co, Ni, Cu, Zn, and Cd might have originated from anthropogenic sources. The results revealed that WQI of the remote lake fell into excellent water quality and urban lake fell into poor water quality, which is also supported by the MI calculation. Moreover, the HQ of Mn in urban lake showed values greater than unity suggesting its health risk to the local inhabitants. The cancer index values indicated “high” risk due to Cr, whereas Cd possesses “very low” cancer risk on local population residing nearby areas. This study provides the useful database and suggests for the regular assessment and policy formulation for safeguarding the natural water bodies in the region. [ABSTRACT FROM PUBLISHER]

Magnetic nanoparticles with monodisperse shape and size were prepared by a simple method and covered by silica. The prepared core-shell Fe3O4@silica nanoparticles were functionalized by amino groups and characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. The synthesized nanoparticles were employed as an adsorbent for removal of Hg2+from aqueous solutions, and the adsorption phenomena were studied from both equilibrium and kinetic point of views. The adsorption equilibriums were analyzed using different isotherm models and correlation coefficients were determined for each isotherm. The experimental data were fitted to the Langmuir–Freundlich isotherm better than other isotherms. The adsorption kinetics was tested for the pseudo-first-order, pseudo-second-order and Elovich kinetic models at different initial concentrations of the adsorbate. The pseudo-second-order kinetic model describes the kinetics of the adsorption process for amino functionalized adsorbents. The maximum adsorption occurred at pH 5.7 and the adsorption capacity for Fe3O4@silica-NH2toward Hg2+was as high as 126.7 mg/g which was near four times more than unmodified silica adsorbent. [ABSTRACT FROM PUBLISHER]

In this study, the relevance of Fenton’s reaction for the treatment of urban anaerobically digested sludge was investigated. In a first part, the impact of the oxidation process on the improvement of the sludge dewaterability was studied. In a second part, the removal of heavy metals from the sludge was examined. Fenton’s reaction was carried out with increasing concentrations of Fe2+and H2O2in 1:10 and 1:1 ratios. Dewaterability of the raw sludge was highly improved: the addition of 36 mM Fe2+and 360 mM H2O2led to specific cake resistance (SCR) and capillary suction time (CST) reductions of 99.8% and 98.8%, respectively. Indeed, under these conditions, SCR and CST of respectively 1.04 × 1011 m kg−1and 18.5 ± 0.2 s were measured, and the treated sludge could be considered as having ‘good dewaterability’. A significant impact was also observed on the removal of heavy metals from the sludge. After 1-h oxidation, Cd, Cr, Cu, Pb and Zn could be removed by 81.1 ± 0.1%, 25.1 ± 0.1%, 87.2 ± 1.1%, 77.3 ± 4.8% and 99.6 ± 0.3%, respectively. These results were consistent with the heavy metals’ fractions in the sludge. It could be concluded that the addition of Fe2+and H2O2in a 1:10 ratio was more effective than in a 1:1 ratio. The results were consistent with the extracellular polymeric substance (EPS) contents in raw and treated sludge, since loosely bound EPS decreased significantly after the treatment. [ABSTRACT FROM PUBLISHER]

The cleaning of large volumes of metal-loaded water formed at closed and active mine sites can be a valuable resource of metals. Active treatment processes are needed to recover these metals for reuse and for better environmental protection of recipient waters. This review evaluates the mechanisms of metal removal and recovery and practical feasibility of mine water treatment in two bioreactor systems: sulfate-reducing bioreactors and bioelectrochemical reactors. The influence of treatment conditions and reactor designs on metal recovery, as well as limitations to intensify the treatment processes, are discussed. High metal removal efficiencies are reported with sulfate-reducing bioreactors, whereas metal recovery, in particular, requires reactor designs and process conditions that differ from those that are primarily applied for sulfate removal. Bioelectrochemical systems offer another route for utilizing synergistic microbial processes for metal recovery, but the performance data is still limited to laboratory- and pilot-scale experiments. [ABSTRACT FROM PUBLISHER]

A new concept of Virus Sensitivity Index (VSI) is defined as the ratio between the first-order inactivation rate constant of a virus,ki, and that of MS2-phage during UV disinfection,kr. MS2-phage is chosen as the reference virus because it is recommended as a virus indicator during UV reactor design and validation by the US Environmental Protection Agency. VSI has wide applications in research, design, and validation of UV disinfection systems. For example, it can be used to rank the UV disinfection sensitivity of viruses in reference to MS2-phage.There are four major steps in deriving the equation betweenHi/Hrand 1/VSI. First, the first-order inactivation rate constants are determined by regression analysis between Log Iand fluence required. Second, the inactivation rate constants of MS2-phage are statistically analysed at 3, 4, 5, and 6 Log Ilevels. Third, different VSI values are obtained from thekiof different viruses dividing by thekrof MS2-phage. Fourth, correlation betweenHi/Hrand 1/VSI is analysed by using linear, quadratic, and cubic models. As expected from the theoretical analysis, a linear relationship adequately correlatesHi/Hrand 1/VSI without an intercept. VSI is used to quantitatively predict the UV fluence required for any virus at any log inactivation (Log I). Four equations were developed at 3, 4, 5, and 6 Log I. These equations have been validated using external data which are not used for the virus development. At Log Iless than 3, the equation tends to under-predict the required fluence at both low Log Isuch as 1 and 2 Log I. At Log Igreater than 3 Log I, the equation tends to over-predict the fluence required. The reasons for these may very likely be due to the shoulder at the beginning and the tailing at the end of the collimated beam test experiments. At 3 Log I, the error percentage is less than 6%. The VSI is also used to predict inactivation rate constants under two different UV disinfection scenarios such as under sunlight and different virus aggregates. The correlation analysis shows that viruses will be about 40% more sensitive to sunlight than to UV254. On the other hand, virus size of 500 nm will reduce their VSI by 10%. This is the first attempt to use VSI to predict the required fluence at any given Log I. The equation can be used to quantitatively evaluate other parameters influencing UV disinfection. These factors include environmental species, antibiotic-resistant bacteria or genes, photo and dark repair, water quality such as suspended solids, and UV transmittance. [ABSTRACT FROM AUTHOR]

Electrical conductivity (EC) in aerosols, snow, and meltwater were evaluated at the headwater of the Urumqi River during the ablation seasons of 2003-2008. The results show that EC in meltwater can indicate the intensity of glacier ablation, which negatively correlated with air temperature and discharge. During the early ablation period, EC presents a fluctuation trend and runoff may be primarily from snow, frozen soil, and groundwater. EC decreases to the lowest level during the peak-flow period and runoff flows rapidly through a hydrological system predominantly in ice-walled conduits. EC increases to the highest level during the late ablation period, and runoff transports slowly through a distributed hydrological system at the ice-rock interface. EC in meltwater is far greater than in aerosols, surface snow, and precipitation, which are closely related to atmospheric circulation and dust loading. EC in snow pits denote the spatial variation of snow melting, the enrichment and loss of dissolved ions, and are affected by air temperature. The key ions to determine EC in meltwater are HCO3-, Ca2+ and SO42-, and its dominant control might be biogeochemical pyrite oxidation coupled with calcite and/or dolomite dissolution. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the optimum extraction conditions for the effective separation and removal of Cu2+, Fe2+, and Fe3+using N-benzoyl-n-phenylhydroxylamine (BPA) as an analytical reagent. An efficient liquid–liquid extraction method was developed for the separation and removal of Cu2+, Fe2+, and Fe3+from environmental waste samples. In this method, BPA was used as a chelating agent and the effect of different parameters– including solvents, pH, stripping agents, extraction time, and the interference of other ions– on the quantitative removal of these metals was investigated. This study demonstrates that chloroform is the most effective solvent for BPA. The maximum extraction of the selected metallic species was found between pH 3 and 5. It was demonstrated that the maximum percentage recovery of the metals can be attained using 1 M HCl as a stripping agent. Optimized conditions of different parameters could be beneficial for industry and environmental laboratories. [ABSTRACT FROM PUBLISHER]

In the present study, microfibrillated cellulose (MFC) was modified by aminopropyltriethoxysilane (APS), hydroxy-carbonated apatite (HAP), or epoxy in order to produce novel nanostructured adsorbents for the removal of hydrogen sulphide (H2S) from the aqueous solutions. Structural properties of the modified MFC materials were examined using a scanning electron microscope, Fourier transform infrared spectroscopy and acid/base titration. These methods were used to verify the presence of nanostructures on the adsorbents surfaces as well as functionalities suitable for H2S adsorption. Adsorption of H2S by prepared adsorbents was investigated in batch mode under different experimental conditions, i.e. varying pH and H2S concentrations. H2S uptake was found to be 103.95, 13.38 and 12.73 mg/g by APS/MFC, HAP/MFC and epoxy/MFC, respectively from 80 mg/L H2S solution. The equilibrium data were best described by the Langmuir isotherm for HAP/MFC and APS/MFC and the Sips isotherm for epoxy/MFC. [ABSTRACT FROM PUBLISHER]

This review is intended to critically convey information on water magnetization and to discuss each application that employs magnetic field as an aid in wastewater treatment. The magnetically assisted wastewater treatments are presented and compared in terms of performances with those of conventional treatment systems. The advantages and limitations of magnetic field application are discussed in order to evaluate their environmental benefits. The main conclusion from the literature review is that magnetic field application has the potential to improve the physical performance in terms of solid-liquid separation mainly through aggregation of colloidal particles. The application is also significant in influencing the biological properties through the improvement of bacterial activity. Both of these enhancements lead towards increase in efficiency of the water and wastewater treatment performances. [ABSTRACT FROM AUTHOR]

Aquatic natural organic matter (NOM) is a heterogeneous mixture of biopolymers and their degradation products that cause harmful by-products during drinking water production. The great variability in NOM composition makes it difficult to completely remove from drinking water by any single technique. The current article reviews the NOM removal by micro-, ultra- and nanofiltration and by hybrid processes combining membrane techniques with other unit processes: coagulation, adsorption, and oxidation, and by membrane bioreactors. [ABSTRACT FROM PUBLISHER]

This present work has explored a novel application of modified Arachis hypogaea (groundnut) husk on mitigation of toxic Pb2+ and Cd2+ ions in aqueous phase. Ecotoxicological assessment of exhausted adsorbent was investigated as per standard OECD guidelines. Standard deviation, correlation coefficient, and the reduced chi square test were evaluated and compared statistically on experimental data. The results showed good sorption capacities--31.62 and 29.78 mgg-1 for Pb2+ and Cd2+ ions, respectively. Pseudo first-order rate kinetics was well correlated for Pb2+ and Cd2+ ions sorption over all kinetic models. The sorption data was in good agreement with the Freundlich isotherm for Pb2+ and the Sips model for Cd2+ ions sorption. The sorption capacity was endo-therinic in nature. Pb2+ ions desorption was three times faster than Cd2+ ions. The sorption mechanism was plausibly explained by spectroscopic techniques. Herein, the tailored abundant agro-waste material is a competitive sorbent and may be exploited in decontamination of metal ions in a wide range of concentrations. Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science and Technology to view the free supplemental file. [ABSTRACT FROM AUTHOR]

This present work has explored a novel application of modified Arachis hypogaea (groundnut) husk on mitigation of toxic Pb2+ and Cd2+ ions in aqueous phase. Ecotoxicological assessment of exhausted adsorbent was investigated as per standard OECD guidelines. Standard deviation, correlation coefficient, and the reduced chi square test were evaluated and compared statistically on experimental data. The results showed good sorption capacities—31.62 and 29.78 mg g−l for Pb2+ and Cd2+ ions, respectively. Pseudo first-order rate kinetics was well correlated for Pb2+ and Cd2+ ions sorption over all kinetic models. The sorption data was in good agreement with the Freundlich isotherm for Pb2+ and the Sips model for Cd2+ ions sorption. The sorption capacity was endothermic in nature. Pb2+ ions desorption was three times faster than Cd2+ ions. The sorption mechanism was plausibly explained by spectroscopic techniques. Herein, the tailored abundant agro-waste material is a competitive sorbent and may be exploited in decontamination of metal ions in a wide range of concentrations. Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science and Technology to view the free supplemental file. [ABSTRACT FROM AUTHOR]

The authors present an overview with critical analysis of technical applicability of various nanoadsorbents such as carbon nanotubes, nano-zerovalent iron, and metal oxides–based and polymeric nanoparticles in treating contaminated water. To highlight their performance, selected information such as synthesis method, pH, dose required, pollutant's concentrations, reaction time, and treatment efficiency is presented based on the literature survey of 276 articles (1989–2010). Their advantages and drawbacks in applications are evaluated. Nanoadsorbents that stand out for outstanding performance are compared to bulk activated carbon. The implications of nanoadsorbents to public health and their way forward for facilitating environmental sustainability are also discussed. [ABSTRACT FROM PUBLISHER]

The purpose of this laboratory study was to investigate the simultaneous impacts of the electro-dewatering process on dry solids (DS) content and mobilization of metals in sewage sludge. The results suggested that the use of polyelectrolytes is necessary in mechanical pressure-driven dewatering and also in electro-dewatering. With polyelectrolyte conditioning, the DS content in the final sludge cake could be increased to 39%. Dewatering with slightly cationic polymer was not effective, but medium, strongly and very strongly cationic polymers performed equally. During electro-dewatering, an increase of voltage from 10 to 40 V resulted in a dryer sludge cake. Polyelectrolyte addition reduced the content of exchangeable metal species and increased less mobile, reducible species in the sludge. Furthermore, the more stable or immobile metal fractions were more likely to remain intact in dewatered sludge. Among heavy metals, Cu and Pb were immobile but Cr, Co, Ni, and Zn could more easily be mobilized during electro-dewatering. The application of high voltage had a direct effect on the migration of metal fractions, whereas, the sludge conditioning by a different cationic polymer had an indirect effect on the migration of these metals during electro-dewatering. [ABSTRACT FROM AUTHOR]

The feasibility of nano–Al2O3 for bromate removal from aqueous solution was assessed in the present study. Batch sorption experiments were performed to examine the influence of various experimental parameters such as contact time, initial bromate concentration, temperature, and pH on the sorption of bromate on nano–Al2O3. Kinetic data revealed that the uptake rate of bromate was rapid in the beginning and 50% adsorption was completed within 10 min and equilibrium was achieved within 120 min. Pseudo–second–order kinetic model was fitted well with the kinetics of the sorption process. The sorption potential of nano–Al2O3 for bromate removal was ∼6.0 mg g−1. The adsorption was found to be an endothermic process and data conform to the Langmuir model. Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science and Technology to view the free supplemental file. [ABSTRACT FROM PUBLISHER]

A novel process combining hydrogen peroxide (H2O2) and radiation emitted by ultraviolet light emitting diodes (UV LEDs) has been investigated. The UV LEDs were used as UV-C light sources emitting radiation in the range 257-277 nm for decomposition of the model substance phenol in water. In addition, the effect of H2O2 to phenol molar ratio and initial phenol concentration was examined. Two parameters, the decomposition efficiency of phenol and characterization of hydroxyl radical (HO•) production from H2O2 when illuminated with UV radiation, were selected to provide detailed information regarding the performance of the UV LEDs in the treatment process. A new concept was introduced to characterize and describe the production of HO• radicals produced when photons were absorbed by H2O2 molecules. The phenol decomposition efficiency at the initial concentration of 100 mg/L was the most pronounced at the lowest emitted wavelength. A significant correlation was found between the phenol decomposition efficiency and the photons absorbed by H2O2 (i.e. formation of radicals). [ABSTRACT FROM AUTHOR]

Electrodewatering with interrupted voltage was set up to investigate the effects of long off-time interruption on solid content in the final sludge cake and the fractionation of macro and trace elements in the sludge matrix. In comparison to continuous direct current (DC) electrodewatering, long off-time interruption had a negative effect on water removal, resulting in a high water content in sludge at anode and the final sludge cake. However, long off-time interrupted electrodewatering significantly increased dry solid (DS) content in the final sludge cake in comparison to control experiments. Removal of Na+ and K+ from sludge was affected by long off-time interruption. The long off-time interruption also negatively influenced the dissolution and migration of macro (Ca, Mg, and Fe) and trace (Ni, Mn, and Zn) metals in sludge cake matrix. The long off-time interrupted voltage application did not have any effect on the chromium concentrations in sludge at the anode; however, the chromium concentrations in the removed water at the anode significantly depended on off-time interruption. [ABSTRACT FROM AUTHOR]

The oxidation of ethylenediaminetetraacetic acid (EDTA) and Na, Ca, Zn, Fe, and Mn EDTA complexes with hydrogen peroxide was studied in aqueous solution with the use of several metallophthalocyanines (MePcS) as catalysts. The impact of pH, temperature, and catalyst/substrate ratio were investigated. The most effective catalytic system under neutral conditions was FePcS-H2O2. In these laboratory-scale experiments, a catalyst/substrate/H2O2 molar ratio of 4:100:2000 was found to be optimal, while the effective reaction temperature was 40-60 °C. When the impact of metal speciation was studied, metal-specific degradation rates in the removal of these compounds were observed: all EDTA-metal complexes except Zn-EDTA were efficiently oxidized within three hours. The most degradable species was Fe(III)-EDTA. Among the catalysts, FePcS was found to be the most active in EDTA degradation. Over 90% of EDTA was removed in the presence of FePcS as catalyst within three hours of reaction time. [ABSTRACT FROM AUTHOR]

A process for the removal of two chlorophenols (2-chlorophenol and 2,4-dichlorophenol) from water using surface modified mango seed waste by adsorption process followed by cement fixation of the phenols-laden adsorbent is investigated. The two main objectives of this study were to develop efficient adsorbent utilizing mango seed waste by physiochemical activation and to an environmentally-friendly disposal of phenols-laden adsorbent into cement by a fixation process. The results of the present study reveal that the modified mango seed adsorbent showed an efficient adsorption potential for chlorophenols removal from water. The maximum adsorption potential of modified mango seed adsorbent for 2-chlorophenol and 2,4-dichlorophenol was 40.6 and 72.3 mg g-1, respectively at 25°C. Adsorption kinetic data of chlorophenols adsorption on mango seed adsorbent could be described more favorably by a pseudo-second-order kinetic model. After the adsorption studies, the phenol-laden adsorbent was immobilized in cement for its ultimate disposal. Leachates from the fixed phenols-laden adsorbent exhibit phenols concentrations lower than the drinking water standards. Results from this study suggest the potential utility of agricultural wastes as one of the most promising activated carbon precursors for phenols removal from water and wastewater and the safe disposal of phenol-laden adsorbent into cement by fixation process. [ABSTRACT FROM AUTHOR]

In this study, the electrochemical oxidation technique was used to oxidize sulphides present in paper mill wastewater. Inactivation of anaerobic bacteria in wastewater was also investigated. Sulphide oxidation was effective during the experiments, and the best efficiency was achieved by the smallest current density used. One of the main oxidants of sulphides during the experiments was oxygen. Anaerobic bacteria were better inactivated with higher initial chloride concentration in wastewater because of electrochemically generated chlorine/hypochlorite. Dissolved oxygen, redox potential and pH values of the wastewater increased because of electrochemically generated oxygen-based oxidants and oxidation reactions occurring on the anode. In general, it can be said that sulphide removal was successful in the present study. [ABSTRACT FROM AUTHOR]

Three tests were conducted using ultrasound alone, ultrasound as an enhancement for electrokinetic test and electrokinetic test alone to compare the removal performance of the three persistent organic pollutants, hexachlorobenzene, phenanthrene, and fluoranthene from low permeability kaolin. Results show that the removal efficiency in ultrasonically enhanced electrokinetic test was the highest among experiments, though the removal rates improved were small only. The assistance of ultrasound in electrokinetic remediation can help reduce these hydrophobic organic compounds by increasing their mobility, desorption for electroosmotic migration, and also by degrading them through free radical oxidation forming during cavitation process. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of ozone to degrade organic compounds of nuclear laundry water was studied at different pH and temperatures and at elevated temperature with hydrogen peroxide. The degradation of non-ionic surfactant and other organic compounds was analyzed by COD, TOC, BOD and molecular weight distribution measurements. Zeta potential measurements were also performed in order to interpret the obtained results. The most favorable degradation conditions were at pH 7 with 43%, 34% and 61% reductions of COD, TOC and BOD, respectively. [ABSTRACT FROM AUTHOR]

This paper presents data on the concentration and chemical partitioning of four heavy metals, iron (Fe), copper (Cu), cadmium (Cd) and lead (Pb) in Great Lake Saimaa (Finland) sediments and moss (Pleurozium schreberi). Elemental analysis was performed by Flame Atomic Absorption Spectrometry and (FAAS) and anodic stripping voltammetry, using multi-element standard solutions. Results showed that the highest metal concentrations of Fe in sediments were recorded for Partakoski village, Mikkeli city and Ristiina with values of 86 mg/kg, 67.1 mg/kg and 63.8 mg/kg, respectively. The highest Cu concentration was observed in Anttola and Partakoski village sediments with values of 8.1 mg/kg and 7.3 mg/kg, respectively. On the contrary, the highest Cd concentration was found in Tetriniemi village and Puumala harbour sediments (0.6 mg/kg and 0.4 mg/kg, respectively) and the highest Pb concentrations were found in Puumala (2.2 mg/kg) and Ristiina (1.7 mg/kg) sediments. On average, the total metal contamination followed the order Partakoski>Mikkeli city>Ristiina>Anttola harbour>Imatra>Puumala harbour>Astuvansalmi>Tetriniemi. The highest amount of Fe was found in moss samples (85.4 mg/kg) from Ristiina and Cu was found to be the chiefly accumulated in moss (10.2 mg/kg) from Anttola. There was ineligible amount of Cd and Pb found in all the moss samples. Partitioning of Fe, Cu, Cd and Pb showed that more than 90% of metal was associated with residual fraction in sediments, with an exception of Cu that was significantly (20% of the total) associated with an organic/sulfide fraction and Fe (22% of the total) was associated with exchangeable/carbonate fraction as well. On the other hand, chemical partitioning of metals in moss samples showed that Cu (up to 90%), Pb (up to 80%) and Fe (up to 60%) were strongly associated with extracellular fraction and Cd showed the highest affinity towards intracellular fraction (up to 70%). Statistical analyses carried out with principal component analysis and cluster analysis methods showed good correlation between Pb, Fe and Cu content and moss as well as sediments. Significant relationship (p<0.05) between different metals was observed for Cu - Cd (0.88), Fe - Pb (0.65), Fe - Cu (0.68), Cu - Pb (0.47) in sediments and moss samples. The metal content in exchangeable and extracellular fractions in sediments and moss samples showed that Cu, Pb and Fe were the most bioavailable elements. [ABSTRACT FROM AUTHOR]

Pure anatase TiO2 nanoparticles and two kinds of TiO2–SnO2 nanocomposite with different amounts of SnO2 nanoparticles (A-S (1-1) and A-S (1-2)) are synthesised. The X-ray diffraction (XRD) pattern is used for the characterisation of the synthesised samples. The XRD results confirmed that synthesised TiO2 nanoparticles have an anatase structure and SnO2 nanoparticles possess a tetragonal structure. The results of TEM reveal that the particle size of the TiO2 nanoparticles is less than 30 nm. Meanwhile, the SnO2 nanoparticle is successfully introduced onto the outer surface of TiO2 nanoparticles. The variation in the removal efficiency of methyl orange as an organic pollutant with UV irradiation time, weight fraction of synthesised photocatalysts and pH is investigated. The obtained results confirm that the removal efficiency of methyl orange increases in respect of the UV irradiation time and weight fraction. In addition, it is observed that the highest and lowest removal efficiencies occur at pH = 3 and pH = 11, respectively. Meanwhile, the results reveal that the removal efficiency of methyl orange is enhanced in respect of the SnO2 nanoparticles content in the synthesised nanocomposite. The analysis of variance investigation reveals that all the main factors have a significant effect on the removal efficiency of pollutant. Meanwhile, the proposed models can accurately predict the variation of the removal efficiency with studied parameters. [ABSTRACT FROM AUTHOR]