Recent Advances in Bimetallic Catalysts for Methane Steam Reforming in Hydrogen Production: Current Trends, Challenges, and Future Prospects.

As energy demand continues to rise and the global population steadily grows, there is a growing interest in exploring alternative, clean, and renewable energy sources. The search for alternatives, such as green hydrogen, as both a fuel and an industrial feedstock, is intensifying. Methane steam reforming (MSR) has long been considered a primary method for hydrogen production, despite its numerous advantages, the activity and stability of the conventional Ni catalysts are major concerns due to carbon formation and metal sintering at high temperatures, posing significant drawbacks to the process. In recent years, significant attention has been given to bimetallic catalysts as a potential solution to overcome the challenges associated with methane steam reforming. Thus, this review focuses on the recent advancements in bimetallic catalysts for hydrogen production through methane steam reforming. The review explores various aspects including reactor type, catalyst selection, and the impact of different operating parameters such as reaction temperature, pressure, feed composition, reactor configuration, and feed and sweep gas flow rates. The analysis and discussion revolve around key performance indicators such as methane conversion, hydrogen recovery, and hydrogen yield.

Removal of pharmaceutically active compounds from water sources using nanofiltration and reverse osmosis membranes: Comparison of removal efficiencies and in-depth analysis of rejection mechanisms.

Trace organic compounds from effluent streams are not completely removed by conventional purification techniques and hence, contaminating groundwater sources. Herein, we report the removal efficiency and rejection mechanisms of three common pharmaceutically active compounds (PhACs); caffeine (CFN), omeprazole (OMZ), and sulfamethoxazole (SMX), using commercial nanofiltration (NF) and reverse osmosis (RO) membranes with different surface characteristics. The RO membranes showed near-complete removal of all PhACs with rejection rates >99%. On the other hand, retention capabilities for the NF membranes varied and were influenced by the characteristics of the PhACs, membranes, and the feed solution. In general, during long-term testing, the rejection did not show much variation and followed a trend compatible with the size exclusion (steric hindrance) mechanism. When a real matrix was used, the rejection of CFN by the more tight NF membranes, HL TFC and NFW decreased by ∼10%, whereas the removal of SMX by the loose NF membrane, XN45, increased by the same ratio. In short-term testing, the rejection of negatively charged SMX increased significantly (∼20-40%) at a higher pH of ∼8 and in the presence of salts. Fouling by the PhACs was more severe on the high-flux NF membranes, HL TFC and XN45, as witnessed by the significant change in Contact angle (CA) values (∼25-50°) as well as the flux decline (∼15%) during long-term testing. To summarize, the removal of PhACs by membranes is a complex phenomenon and depends upon a combination of several factors.

Low Overpotential Electrochemical Reduction of CO2 to Ethanol Enabled by Cu/CuxO Nanoparticles Embedded in Nitrogen-Doped Carbon Cuboids.

The electrochemical conversion of CO2 into value-added chemicals is a promising approach for addressing environmental and energy supply problems. In this study, electrochemical CO2 catalysis to ethanol is achieved using incorporated Cu/CuxO nanoparticles into nitrogenous porous carbon cuboids. Pyrolysis of the coordinated Cu cations with nitrogen heterocycles allowed Cu nanoparticles to detach from the coordination complex but remain dispersed throughout the porous carbon cuboids. The heterogeneous composite Cu/CuxO-PCC-0h electrocatalyst reduced CO2 to ethanol at low overpotential in 0.5 M KHCO3, exhibiting maximum ethanol faradaic efficiency of 50% at -0.5 V vs. reversible hydrogen electrode. Such electrochemical performance can be ascribed to the synergy between pyridinic nitrogen species, Cu/CuxO nanoparticles, and porous carbon morphology, together providing efficient CO2 diffusion, activation, and intermediates stabilization. This was supported by the notably high electrochemically active surface area, rich porosity, and efficient charge transfer properties.

A First-Principles Study on the Multilayer Graphene Nanosheets Anode Performance for Boron-Ion Battery.

Advanced battery materials are urgently desirable to meet the rapidly growing demand for portable electronics and power. The development of a high-energy-density anode is essential for the practical application of B3+ batteries as an alternative to Li-ion batteries. Herein, we have investigated the performance of B3+ on monolayer (MG), bilayer (BG), trilayer (TG), and tetralayer (TTG) graphene sheets using first-principles calculations. The findings reveal significant stabilization of the HOMO and the LUMO frontier orbitals of the graphene sheets upon adsorption of B3+ by shifting the energies from -5.085 and -2.242 eV in MG to -20.08 and -19.84 eV in 2B3+@TTG. Similarly, increasing the layers to tetralayer graphitic carbon B3+@TTG_asym and B3+@TTG_sym produced the most favorable and deeper van der Waals interactions. The cell voltages obtained were considerably enhanced, and B3+/B@TTG showed the highest cell voltage of 16.5 V. Our results suggest a novel avenue to engineer graphene anode performance by increasing the number of graphene layers.

Layered double hydroxide-modified membranes for water treatment: Recent advances and prospects.

Layered double hydroxides (LDHs) represent an exciting class of two-dimensional inorganic materials with unique physicochemical properties. They have been widely employed in water treatment due to their high surface areas, excellent ion exchange capacities, and highly tunable structures. They have also been employed in the fabrication and development of membranes for water treatment. 2D nanostructures as well as tailorable "structure forming units", surface functionalization with desired moieties, and interlayer galleries with adjustable heights and internal compositions make them attractive materials for membrane separations. This paper critically overviews the recent advancements in the synthesis and applications of LDH based membranes in water purification. The synthesis techniques and the effect of LDH incorporation into different membrane compositions have been described. LDH-based membranes showed excellent antifouling capability and improved water flux due to enhanced hydrophilicity. Such membranes have been successfully used for the treatment of inorganics, organics from environmental water samples. This review will be useful for understanding the current state of the LDH-based membranes for water purification and defining future research dimensions. In the end, we highlight some challenges and future prospects for the efficient application of LDH-based membranes in water decontamination.

Novel Porous Organic Polymer for the Concurrent and Selective Removal of Hydrogen Sulfide and Carbon Dioxide from Natural Gas Streams.

Natural gas sweetening currently requires multistep, complex separation processes to remove the acid gas contaminants, carbon dioxide and hydrogen sulfide. In addition to being widely recognized as energy inefficient and cost-intensive, the effectiveness of this conventional process also suffers considerably because of limitations of the sorbent materials it employs. Herein, we report a new porous organic polymer, termed KFUPM-5, that is demonstrated to be effective in the concurrent separation of both hydrogen sulfide and carbon dioxide from a mixed gas stream at ambient conditions. To understand the ability of KFUPM-5 to selectively capture these gas molecules, we performed both pure-component thermodynamic and mixed gas kinetic adsorption studies and correlated these results with theoretical molecular simulations. Our results show that the underlying polar backbone of KFUPM-5 provides favorable adsorption sites for the selective capture of these gas molecules. The outcome of this work lends credence to the prospect that, for the first time, porous organic polymers can serve as sorbents for industrial natural gas sweetening processes.

An in-vitro evaluation of fluoride content and enamel remineralization potential of two toothpastes containing different bioactive glasses.

BACKGROUND: Many novel biomaterials have been incorporated in toothpastes to promote remineralization of tooth structure. OBJECTIVES: This study was carried out to compare the discrepancies between declared and actual total fluoride (TF) or total soluble fluoride (TSF) concentration of two modern toothpastes containing bioactive glasses; these were also assessed for their remineralization potential. MATERIALS AND METHODS: The TF and TSF concentration were assessed using a fluoride ion selective electrode. Enamel remineralization was evaluated through micro-hardness analysis. Eighteen enamel blocks were divided into three groups: 1 (n = 6; control), 2 (n = 6; Novamin® toothpaste), and 3 (n = 6; BiominF® toothpaste). The specimens were demineralized by 6 wt% citric acid (pH = 2.2). Subsequently, the specimens in group 1 were kept in artificial saliva (AS), while the specimens in groups 2 and 3 were stored in AS + Novamin® and AS + Biomin®, respectively. RESULTS: Both Novamin® or BiominF® showed less TF concentration than their label claims. BiominF® had more TF and TSF compared to Novamin® (p < 0.05). The BiominF® toothpaste presented higher micro-hardness values on remineralization. CONCLUSION: BiominF® toothpaste demonstrated more fluoride content and greater potential to promote remineralization of demineralized human enamel compared to Novamin®.

Reduction of DBPs in synthetic water by indoor techniques and its implications on exposure and health risk.

Disinfection byproducts (DBPs) in municipal supply water have been a concern. Many DBPs have been characterized as possible and probable human carcinogens, which can pose elevated cancer risks through lifetime exposure to municipal supply water. Few DBPs are regulated in many countries to control human exposure and risk from DBPs. In risk assessment studies, concentration of DBPs in water distribution systems is often used, whereas populations are typically exposed to indoor tap water. Through employing several techniques, DBPs can be reduced prior to water consumption, which is likely to reduce human exposure and risk of DBPs. This study investigated six indoor techniques in reducing trihalomethanes (THMs) and haloacetic acids (HAAs) in synthetic water and the effects of these techniques on exposure and risk. The techniques are: S1, S2: storing water in a refrigerator with and without lids respectively; S3, S4: boiling water for 1 min followed by storing in a refrigerator with and without lids respectively; S5, S6: filtering water using new and used granular activated carbon (GAC) filters and storing in a refrigerator without lids. Storing of water (S1, S2) reduced THMs in the range of 14.8-47.2% while boiling (S3, S4) and filtration (S5, S6) reduced THMs in the range of 77.3-92.8%. In S1-S4 techniques, HAAs were not reduced significantly while in S5 - S6 techniques, HAAs were reduced in the range of 64.7-69.8%. In S3-S6 techniques, overall cancer and non-cancer risks were reduced by 45.5-82.6% and 26.3-80.0% respectively. The findings might prove useful in understanding DBPs exposure, associated risks, strategies to minimize exposure to these contaminants and updating regulatory guidelines for better protection of health risks from DBPs.

Yttria-based sol-gel coating for capillary microextraction online coupled to high-performance liquid chromatography.

This work about the development of yttria-based polymeric coating using [bis(hydroxyethyl) amine] terminated polydimethylsiloxanes and yttrium trimethoxyethoxide inside the capillary. The coated capillary was utilized for online capillary microextraction and high-performance liquid chromatography analysis. The prepared coating material was characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectrometry, and thermogravimetric analysis. The coated capillary with polymer presented better extraction efficiency compared with the pure yttria-based coated capillary with applicability in extreme pH environments (pH 0-pH 14). Excellent extraction towards polyaromatic hydrocarbons, aldehydes, ketones, alcohols, phenols, and amides was observed with limit of detection ranging from 0.18 to 7.35 ng/mL (S/N = 3) and reproducibility in between 0.6 and 6.8% (n = 3). Capillary-to-capillary extraction analysis has presented reproducibility between 4.1 and 9.9%. The analysis provided linear response for seven selected phenols in the range of 5-200 ng/mL with R2 values between 0.9971 and 0.9998. The inter-day, intra-day, and capillary-to-capillary reproducibility for phenols was also <10%. Real sample analysis by spiking 5, 50, and 200 ng/mL of phenols in wastewater and pool-water produced recovery between 84.7 and 94.3% and reproducibility within 7.6% (n = 3).

4-phenyl-1,2,3-triazole functionalized mesoporous silica SBA-15 as sorbent in an efficient stir bar-supported micro-solid-phase extraction strategy for highly to moderately polar phenols.

A simple and effective strategy for the extraction of highly to moderately polar phenols in water samples was developed by synthesizing a series of 4-phenyl-1,2,3-triazole functionalized SBA-15 sorbents (xN3-Ph-SBA-15; x = 2 - 10 wt%) via two steps: azide functionalization of SBA-15 and its click reaction with phenylacetylene. The formed sorbents, which have a blend of both polar (1,2,3-triazole) and non-polar (long chain alkyl groups) sites were characterized using magic angle spinning NMR, surface area, pore size/pore volume N2 adsorption-desorption isotherms, scanning electron microscopy, and Fourier transform infrared spectroscopy. The surface area and pore size/pore volume were seen to decrease with increasing loading of 4-phenyl-1,2,3-triazole. The sorbents were used in a stir bar-supported micro-solid-phase extraction (SB-µ-SPE) for seven selected phenols in 10 mL water samples, and in combination with gas chromatography - mass spectrometry (GC-MS). A wide number of parameters were studied in the method optimization: 10N3-Ph-SBA-15 was the best sorbent which performed better using 20 mg dosage; 15 min extraction time; 300 µL of ethyl acetate as desorption solvent, 20 min desorption time; and ionic strength set at 0.5 g NaCl. The approach provided the desired linearity range for all tested phenols with R2 value up to 0.9989 and detection limit (LOD) of 0.23-0.37 ng mL-1. Relative standard deviation (RSD) and relative recovery experiments were tested using phenols spiked at 1, 100 and 400 ng mL-1. RSD values were calculated in the range of 2.3-7.5% and the relative recoveries in the wastewater matrix successfully presented a range of 88.5-99.2%.

Total and soluble fluoride concentration present in various commercial brands of children toothpastes available in Saudi Arabia - A pilot study.

OBJECTIVE: The aim of this pilot study was to perform chemical analysis and investigate the total and soluble fluoride concentrations in various brands of children toothpastes. MATERIALS AND METHODS: Three samples of five different commercial brands of children toothpastes were collected and divided into five groups; group A - Biorepair Oral Care toothpaste containing no fluoride (control), group B - Signal Kids Strawberry toothpaste having 500 ppm fluoride, group C - Aquafresh Milk Teeth toothpaste having 500 ppm fluoride, group D - Aquafresh Little Teeth toothpaste having 500 ppm fluoride, and group E - Siwak F Junior having 400 ppm F. The total fluoride (TF) and total soluble fluoride (TSF) concentration of the toothpastes was determined using fluoride ion selective electrode. Data were analysed using Paired sample t-test. RESULTS: The measured TF values were inconsistent with that of the declared concentrations by the manufacturers. Mean TF found in the toothpastes ranged between 2.37 and 515.74 ppm whereas, the mean TSF ranged between 2.00 and 503.4 ppm. For two groups, TF was more than the declared TF whereas for the other three groups, it was less than the declared concentration. All the differences between the declared and observed TF concentration were statistically significant (p < .05) except for one group. All the toothpastes demonstrated mean TSF slightly lower than their respective observed mean TF concentrations. CONCLUSION: The analysis of TF and TSF concentrations revealed variations from the labelled claims. Therefore, some of the toothpastes may have doubtful anti-caries effectiveness owing to deficiency of total and soluble fluoride.

Urea functionalized surface-bonded sol-gel coating for on-line hyphenation of capillary microextraction with high-performance liquid chromatography.

Sol-gel urea functionalized-[bis(hydroxyethyl)amine] terminated polydimethylsiloxane coating was developed for capillary microextraction-high performance liquid chromatographic analysis from aqueous samples. A fused silica capillary is coated from the inside with surface bonded coating material and is created through in-situ sol-gel reaction. The urea-functionalized coating was immobilized to the inner surface of the capillary by the condensation reaction of silanol groups of capillary and sol-solution. The characterization of the coating material was successfully done by using X-ray photoelectron spectroscopy, thermogravimetric analysis, field emission scanning electron microscope, and energy dispersive X-ray spectrometer. To make a setup of online capillary microextraction-high performance liquid chromatography, the urea functionalized capillary was installed in the HPLC manual injection port. The analytes of interest were pre-concentrated in the coated sampling loop, desorbed by the mobile phase, chromatographically separated on C-18 column, and analyzed by UV detector. Sol-gel coated capillaries were used for online extraction and high-performance liquid chromatographic analysis of phenols, ketones, aldehydes, and polyaromatic hydrocarbons. This newly developed coating showed excellent extraction for a variety of analytes ranging from highly polar to non-polar in nature. The analysis using sol-gel coating showed excellent overall sensitivity in terms of lower detection limits (S/N = 3) for the analytes (0.10 ng mL-1-14.29 ng mL-1) with acceptable reproducibility that is less than 12.0%RSD (n = 3). Moreover, the capillary to capillary reproducibility of the analysis was also tested by changing the capillary of the same size. This provided excellent%RSD of less than 10.0% (n = 3).

Ultra-deep adsorptive desulfurization of fuels on cobalt and molybdenum nanoparticles loaded on activated carbon derived from waste rubber.

The role of cobalt and molybdenum nanoparticles loaded on activated carbon (AC) on the adsorptive desulfurization ability of sulfur-containing compounds was investigated under ambient conditions. The AC was first synthesized and activated, followed by incorporation of the cobalt (Co), molybdenum (Mo) and both Co and Mo nanoparticles. The adsorption activity parameters of the developed composites were determined using surface characterization and N2 physisorption techniques. The prepared composites were evaluated for simultaneous adsorption of sulfur compounds from fuels. The AC/CoMo composite showed better adsorption properties than pure AC, AC/Co and AC/Mo composites for the removal of thiophene (T), benzothiophene (BT), dibenzothiophene (DBT), 5-methyl-1-benzothiophene (MBT), 4,6-dimethyldibenzothiophene (DMDBT) and 4-methyldibenzothiophene (MDBT). The order of the thiophene compounds removal was found to be Thiophene < BT < DBT < MBT ≤ MDBT ≤ DMDBT. The enhanced desulfurization performance of the AC/CoMo composite was attributed to the increase in the surface area achieved through impregnation of both Co and Mo.

Determination of haloacetic acids in water using layered double hydroxides as a sorbent in dispersive solid-phase extraction followed by liquid chromatography with tandem mass spectrometry.

In the present study, highly efficient and simple dispersive solid-phase extraction procedure for the determination of haloacetic acids in water samples has been established. Three different types of layered double hydroxides were synthesized and used as a sorbent in dispersive solid-phase extraction. Due to the interesting behavior of layered double hydroxides in an acidic medium (pH˂4), the analyte elution step was not needed; the layered double hydroxides are simply dissolved in acid immediately after extraction to release the analytes which are then directly introduced into a liquid chromatography with tandem mass spectrometry system for analysis. Several dispersive solid-phase extraction parameters were optimized to increase the extraction efficiency of haloacetic acids such as temperature, extraction time and pH. Under optimum conditions, good linearity was achieved over the concentration range of 0.05-100 µg/L with detection limits in the range of 0.006-0.05 µg/L. The relative standard deviations were 0.33-3.64% (n = 6). The proposed method was applied to different water samples collected from a drinking water plant to determine the concentrations of haloacetic acids.

Collision induced dissociations of non-derivatized and trimethylsilyl-derivatized estradiols: similarities in fragmentation patterns.

Fragmentation mechanisms of estradiol and trimethylsilyl (TMS)-derivatized estradiol were studied by triple quadrupole tandem mass spectrometry (MSMS) and density functional theory (DFT) at B3LYP/6-311G(d,p) level. Collision induced dissociations (CID) of estradiol give product ions that are associated with the cleavage of B, C and D rings. Characteristic fragments from the cleavage of the aromatic ring A were not identified, and this was confirmed with both labeled estradiol and trimethylsilyl (TMS)-derivatized estradiol. The mechanisms are based on charge-site directed, radical-directed and charge remote fragmentations that are consistent with previous studies of steroids. CID spectra show ion pairs at m/z: 145/146, 157/158, 185/186, 211/213 and 225/226 with significant intensities, suggesting that these pairs are not from isotopic contributions. The mechanisms show similarities with some minor differences in the fragmentation patterns between the non-derivatized and the TMS-derivatized estradiol.

Determination of N-nitrosamines by automated dispersive liquid-liquid microextraction integrated with gas chromatography and mass spectrometry.

An automated dispersive liquid-liquid microextraction integrated with gas chromatography and mass spectrometric procedure was developed for the determination of three N-nitrosamines (N-nitroso-di-n-propylamine, N-nitrosopiperidine, and N-nitroso di-n-butylamine) in water samples. Response surface methodology was employed to optimize relevant extraction parameters including extraction time, dispersive solvent volume, water sample pH, sodium chloride concentration, and agitation (stirring) speed. The optimal dispersive liquid-liquid microextraction conditions were 28 min of extraction time, 33 µL of methanol as dispersive solvent, 722 rotations per minute of agitation speed, 23% w/v sodium chloride concentration, and pH of 10.5. Under these conditions, good linearity for the analytes in the range from 0.1 to 100 µg/L with coefficients of determination (r(2) ) from 0.988 to 0.998 were obtained. The limits of detection based on a signal-to-noise ratio of 3 were between 5.7 and 124 ng/L with corresponding relative standard deviations from 3.4 to 5.9% (n = 4). The relative recoveries of N-nitroso-di-n-propylamine, N-nitrosopiperidine, and N-nitroso di-n-butylamine from spiked groundwater and tap water samples at concentrations of 2 µg/L of each analyte (mean ± standard deviation, n = 3) were (93.9 ± 8.7), (90.6 ± 10.7), and (103.7 ± 8.0)%, respectively. The method was applied to determine the N-nitrosamines in water samples of different complexities, such as tap water, and groundwater, before and after treatment, in a local water treatment plant.

Highly efficient and selective oxidation of aromatic alcohols photocatalyzed by nanoporous hierarchical Pt/Bi2WO6 in organic solvent-free environment.

Selective conversion of aromatic alcohols into corresponding aldehydes is important from energy and environmental stance. Here, we describe highly selective (>99%) and efficient conversion (>99%) of aromatic alcohols (e.g., 4-methoxybenzyl alcohol and 4-nitrobenzyl alcohol) into their corresponding aldehydes in the presence of Pt-modified nanoporous hierarchical Bi2WO6 spheres in water under simulated sunlight at ambient conditions. Overoxidation of p-anisaldehyde, formed during photooxidation process, was not observed until comprehensive alcohol oxidation was attained. Furthermore, the catalyst showed substantial oxidation under dark and course of conversion was different than that of under light. Dependency of alcohol oxidation on substrate concentration, photocatalyst amount, and Pt loading was studied. The effect of various radical scavengers was investigated, and the rate-determining step was elucidated. It has been envisaged that the reduction site of semiconductor photocatalysts plays more decisive role in determining the selectivity as alcohol preferably get oxidized over that of water. Furthermore, the chemical stability and recyclability of the photocatalyst were investigated.

Disinfection byproducts in swimming pool: occurrences, implications and future needs.

Disinfection of swimming pool water is essential to deactivate pathogenic microorganisms. Many swimming pools apply chlorine or bromine based disinfectants to prevent microbial growth. The chlorinated swimming pool water contains higher chlorine residual and is maintained at a higher temperature than a typical drinking water distribution system. It constitutes environments with high levels of disinfection by-products (DBPs) in water and air as a consequence of continuous disinfection and constant organic loading from the bathers. Exposure to those DBPs is inevitable for any bather or trainer, while such exposures can have elevated risks to human health. To date, over 70 peer-reviewed publications have reported various aspects of swimming pool, including types and quantities of DBPs, organic loads from bathers, factors affecting DBPs formation in swimming pool, human exposure and their potential risks. This paper aims to review the state of research on swimming pool including with the focus of DBPs in swimming pools, understand their types and variability, possible health effects and analyze the factors responsible for the formation of various DBPs in a swimming pool. The study identifies the current challenges and future research needs to minimize DBPs formation in a swimming pool and their consequent negative effects to bathers and trainers.

Determination of phenoxy herbicides in water samples using phase transfer microextraction with simultaneous derivatization followed by GC-MS analysis.

A sensitive and accurate method for the determination of two model phenoxy herbicides, 4-chloro-2-methylphenoxy acetic acid and 4-chloro-2-methylphenoxy propanoic acid, in water is explained. This method utilizes a simple phase transfer catalyst-assisted microextraction with simultaneous derivatization. Factors affecting the performance of this method including pH of the aqueous matrix, temperature, extraction duration, type and amount of derivatization reagents, and type and amount of the phase transfer catalyst are examined. Derivatization and the use of phase transfer catalyst have proven to be especially vital for the resolution of the analytes and their sensitive determination, with an enrichment factor of 288-fold for catalyzed over noncatalyzed procedure. Good linearity ranging from 0.1 to 80 µg L(-1) with correlation of determination (r(2) ) between 0.9890 and 0.9945 were obtained. Previous reported detection limits are compared with our new current method. The low LOD for the two analytes (0.80 ng L(-1) for 4-chloro-2-methylphenoxy propanoic acid and 3.04 ng L(-1) for 4-chloro-2-methylphenoxy acetic acid) allow for the determination of low concentrations of these analytes in real samples. The absence of matrix effect was confirmed through relative recovery calculations. Application of the method to seawater and tap water samples was tested, but only 4-chloro-2-methylphenoxy propanoic acid at concentrations between 0.27 ± 0.01 and 0.84 ± 0.06 µg L(-1) was detected in seawater samples.

Analytical method development using functionalized polysulfone membranes for the determination of chlorinated hydrocarbons in water.

In this study, functionalized polysulfone membrane has been utilized as a sorbent for the extraction of chlorinated hydrocarbons (CHCs) in water samples. Two different functionalized polysulfones (i) phosphonic acid functionalized polysulfone (PPSU-A) with different forms (cross-linked and non cross-linked) membranes and (ii) phosphonic ester functionalized polysulfone (PPSU-E) with different forms (cross-linked and non cross-linked) were evaluated for the extraction of CHCs in water. A 10 ml of spiked water sample was extracted with 50mg piece of the functionalized membrane. After extraction, the membrane was desorbed by organic solvent and the extract was analyzed by gas chromatography-mass spectrometry. Eight CHCs, 1,3,5-trichlorobenzene (1,3,5-TCB), 1,2,3-trichlorobenzene (1,2,3-TCB), 1,1,2,3,4,4-hexachloro-1,3-butadiene (HCBD), 1,2,4-trichloro-3-methylbenzene (TCMB), 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB), pentachlorobenzene (PeCB) and hexachlorobenzene (HCB) were used as model compounds. Experimental parameters such as extraction time, desorption time, types of polymer membrane as well the nature of desorption solvent were optimized. Using optimum extraction conditions calibration curves were linear with coefficients of determination between 0.9954 and 0.9999 over wide range of concentrations (0.05-100 µgl(-1)). The method detection limits (at a signal-to-noise ratio of 3) were in the range of 0.4-3.9 ng l(-1). The proposed method was evaluated for the determination of CHCs in drinking water samples.