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The effect of pre-ozonation of a synthetic wastewater spiked with 2,4-dichlorophenol prior to a biological treatment was investigated experimentally by using a pilot-scale bioreactor. The pre-ozonated wastewater was characterized by a brown color, probably due to the formation of typical intermediate products such as quinones or their derivatives. Because also under steady conditions a brown effluent of the bioreactor was observed, accompanied with an increased chemical oxygen demand of the effluent, it was assumed that the intermediate products were not completely biodegradable. However, a decreasing sludge volume index indicated the enhanced sludge settleability. Without pre-treatment, the complete biodegradation of 2,4-dichlorophenol occurred. However, due to the presence of small particles, the effluent was not clear, even not after centrifugation. Moreover, the higher sludge volume index indicated the hampered settling of the sludge. Under both investigated circumstances, the nitrification and denitrification process was not affected. [ABSTRACT FROM AUTHOR]

Trace bromide (Br − ) released from industrial effluents or brominated compounds is able to directly react with peroxymonosulfate (PMS) to generate a series of reactive oxidants which can oxidize and also halogenate organics. We report the identification and evolution of by-products during 2,4,6-trichlorophenol (TCP) degradation in the presence of PMS and trace Br − . The influencing factors, including Br − concentration and pH, were investigated. The depletion of TCP was accelerated with increasing trace Br − concentration (0–0.2 mM) and was affected by the initial pH (3.0–7.0). The chlorinated and brominated compounds were identified in simulated wastewater during treatment with PMS. Notably, the potential formation of chlorobromoaromatic by-products was demonstrated for the first time in the presence of PMS and trace Br − . The possible reaction pathways of TCP and its derivatives are discussed. These findings have important implications for the future applications of PMS-based oxidation processes. [ABSTRACT FROM AUTHOR]

The long-proposed use of open-cell polyurethane foam (PUF) as a convenient ‘solid-phase extractant’ for aqueous organic compounds has been hindered by a critical lack of understanding on the underlying specificity of its extraction mechanism. In this work, we tasked ourselves to understand the hierarchy of molecular structure, properties, and partitioning characteristics of compounds in PUF and aqueous phase by targeting lipophilic phenolic compounds (LPCs) as a group of primary targets for PUF extraction. Using six structurally related bisphenol analogs as comparative probes, we identified molecular lipophilicity and H-bond acidity as key molecular attributes that governed their extractability by PUF. Molecular modeling study on H-bonding interactions between PUF surrogates, bisphenols, and water molecules elucidated the governing effect of H-bond acidity in the binding affinity of guest molecules onto PUF lone-pair donors. A holistic view must be adopted when assessing the extractability of LPCs with reactive lone-pair donors e.g. bisphenol S which forms multidentate H-bond adducts with water molecules. We validated our theory on two model groups of monofunctional LPCs, alkylphenols and chlorophenols, with the observation that the presence of a second proton-donating moiety dramatically enhanced the extractability of bisphenol molecules. The specificity of PUF rendered it selective towards compounds with correlating molecular attributes against other structural analogs and co-existing matrix organics. For LPCs, the PUF macromolecular structure can be conceptualized as a flexible 'molecular zipper network' that is most affinitive towards nonionic, permeable, and lipophilic guest molecules with multiple reactive proton donors. [ABSTRACT FROM AUTHOR]

The present study was conducted to degrade and detoxify 2-chlorophenol (2-CP) under UV irradiation in the presence of titanium dioxide (TiO2) and hydrogen peroxide (H2O2). The treatment efficiency was evaluated on the basis of degradation and cytotoxicity reduction as well as biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total organic carbon (TOC) removal. The process variables such as TiO2, pH, UV irradiation time and H2O2 were optimized. Central composite design in combination with response surface methodology was employed to optimize the process variables. A quadratic model was proposed to predict the treatment efficiency and analysis of variance was used to determine the significance of the variables. The correlation between the experimental and predicted degradation was confirmed by the F and P values (<0.05). The coefficient of determination (R² = 0.99) were high enough to support the validity of developed model. At optimized conditions, up to 92% degradation of 2-CP was achieved with 3.5 × 10-4 s-1 rate constant. Significant reductions in BOD, COD and TOC values were also achieved. Cytotoxicity was evaluated using bioassays and it was observed that UV/TiO2/H2O2 reduced the cytotoxicity considerably. It is concluded that UV/TiO2/H2O2 could possibly be used to detoxify 2-CP in industrial wastewater. [ABSTRACT FROM AUTHOR]

Aiming to remove chlorophenols from aqueous solution, carbon nanotube (CNT) hybrid polymer beads were fabricated via the phase inversion method, and were adopted as adsorbents to remove p -chlorophenol in this study. The CNT hybrid bead was composed of a smooth outer surface and hierarchical porous inner structure, with worm-like CNTs lying on/embedded in the polymer slices. The incorporation of CNTs in the polymer beads resulted in a dramatically improvement of the surface area. The adsorption kinetics and isotherms of p -chlorophenol from aqueous solutions on CNT hybrid adsorbents were studied, and the impacts of temperature and pH value on the adsorption were also explored. The adsorption capacity of CNT hybrid adsorbents towards p -chlorophenol was significantly superior to that of the neat polymer adsorbent and pristine CNT. And the CNT hybrid adsorbents also showed an outstanding separation performance from water treatment system after adsorption. The adsorption process of p -chlorophenol on CNT hybrid adsorbents was found to be an exothermic process, and physical adsorption was the predominant mechanism. The neutral p -chlorophenol molecule was a more effective form for adsorption than was the ionic form. The interaction between p -chlorophenol and the CNT hybrid adsorbents responsible for the adsorption was assumed mainly non-polar forces such as hydrophobic interactions and π–π electron coupling. [ABSTRACT FROM AUTHOR]

The determination of chlorophenols in urine is an established approach for the assessment of human exposure to these ubiquitous environmental pollutants. However, an analytical procedure which enables the separate determination of all components of this substance group was still lacking. For this task we developed a method using enzymatic hydrolysis, solid phase extraction, derivatisation with bis(trimethylsilyl)trifluoroacetamide and gas chromatography-tandem-mass spectrometry with isotope dilution. The chromatographic conditions provided baseline separation of all 19 chlorophenol derivatives. Precision within series did not exceed 15% although for urinary concentrations of 1 μg L −1 . The recovery was found to be well for most of the parameters. Limits of quantifications ranged between 0.04 and 0.10 μg L −1 . The present method is the first procedure which enables the simultaneous trace analysis of the full spectrum of chlorophenols in human urine. Thus, it may be a suitable benchmark procedure for the human biomonitoring of the exposure to these compounds in population studies. [ABSTRACT FROM AUTHOR]

The catalytic hydrodechlorination of 2,4-dichlorophenol (2,4-DCP) as a model pollutant has been conducted for evaluation of optimum base in laboratory scale cocurrent downflow contactor reactor (CDCR). 2,4-DCP was completely dechlorinated with an initial concentration of 3.0 and 6.0 mmol, at 303 K temperature and 0.1 MPa pressure. Hydrogen flow rate was remained at 0.3 L/min, and catalyst loading of 0.2 g/L of 5 % Palladium/carbon (Pd/C) catalyst was used. Different bases like triethylamine (N(CH2CH3)3), sodium acetate trihydrate (CH3COONa · 3H2O), sodium hydroxide (NaOH), ammonium hydroxide (NH4OH) and potassium hydroxide (KOH) were used for evaluation of optimum base. The same reaction was studied without base, and it was observed that more reaction time was required for hydrodechlorination of 2,4-DCP as compared to the presence of a base as production of HCl decreased the rate of reaction. During the hydrodechlorination reaction, 4-chlorophenol (4-CP) was also formed as an intermediate product along with 2-chlorophenol (2-CP). Significant amount of 4-CP produced when no alkali or weak alkalis like N(CH2CH3)3, CH3COONa · 3H2O were used. No inhibitory effects of N(CH2CH3)3, were observed during hydrodechlorination reaction of 2,4-DCP in CDCR. The addition of strong inorganic base helped with dechlorination of 2,4-DCP in predominantly fast reaction, and rate of neutralization using different bases was observed and found that the KOH had highest rate of reaction and CH3COONa · 3H2O had lowest, whereas NaOH, NH4OH and N(CH2CH3)3 had intermediate reaction time. The presence of strong base kept pH in the basic region after neutralization of all HCl formed during the reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new waste derived Cr 2 O 3 /carbon/TiO 2 nanocomposite was successfully synthesized. • TiO 2 impregnation influence on the degradation of chlorophenol was investigated. • The carbon act as a co-catalyst for efficient separation electron and hole pairs. • Synergistic effect endowed Cr 2 O 3 /carbon/TiO 2 composite with improved TiO 2 addition. Highly stable semiconducting, photocatalytic Cr 2 O 3 /carbon/TiO 2 composites have been successfully synthesized from toxic chrome-tanned buffing dust. The presence of Cr 2 O 3 (eskolaite) and impregnation of TiO 2 (anatase) were confirmed through XRD and XPS analysis. Moreover, it was observed that Cr 2 O 3 /carbon/TiO 2 composite bandgap decreased compared to TiO 2. The synergetic effect of Cr 2 O 3 /carbon/TiO 2 composite was evaluated by degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) using light energy sources of 254 nm and 365 nm. Nearly 100% of 2-CP and 4-CP was degraded within 30 min following first-order kinetics, and the nanocomposite (10% ACTi) showed seven and two times higher activity than TiO 2 and Cr 2 O 3 /carbon materials. Degradation efficiency was further confirmed by HPLC and CV analysis. The higher degradation activity noted was attributed to the generation of hydroxyl radicals, which was confirmed by fluorescence spectroscopy analysis. Furthermore, the nanocomposite is highly stable even after 96 h of reaction, which was confirmed by XRD analysis. The results conclude that waste materials can be utilized for synthesizing semiconducting photocatalytic materials. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study on the impact of organic impurities contained in water (phenol, chlorophenol, chloroform, formaldehyde, and acetaldehyde) on the stability of nectar components: sucrose, citric acid, vitamins A and C, and B group vitamins. A reduction in the concentrations of the main components of nectars and priority contaminants, except for chloroform, has been established. The mechanism of interaction of sucrose, citric acid, and vitamins contained in nectars with phenol, chlorophenol, chloroform, formaldehyde, and acetaldehyde has been substantiated theoretically.

Anaerobic reductive dechlorination of 2,3-dichlorophenol (2,3DCP) and 2,4,6-trichlorophenol (2,4,6TCP) was investigated in microcosms from River Nile sediment. A stable sediment-free anaerobic microbial consortium reductively dechlorinating 2,3DCP and 2,4,6TCP was established. Defined sediment-free cultures showing stable dechlorination were restricted to ortho chlorine when enriched with hydrogen as the electron donor, acetate as the carbon source, and either 2,3-DCP or 2,4,6-TCP as electron acceptors. When acetate, formate, or pyru­vate were used as electron donors, dechlorination activity was lost. Only lactate can replace dihydrogen as an electron donor. However, the dechlorination potential was decreased after successive transfers. To reveal chlororespiring species, the microbial community structure of chlorophenol-reductive dechlorinating enrichment cultures was analyzed by PCR-denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Eight dominant bacteria were detected in the dechlorinating microcosms including members of the genera Citrobac­ter, Geobacter, Pseudomonas, Desulfitobacterium, Desulfovibrio and Clostridium. Highly enriched dechlorinating cultures were dominated by four bacterial species belonging to the genera Pseudomonas, Desulfitobacterium, and Clostridium. Desulfitobacterium represented the major fraction in DGGE profiles indicating its importance in dechlorination activity, which was further confirmed by its absence resulting in complete loss of dechlorination. Reductive dechlorination was confirmed by the stoichiometric dechlorination of 2,3DCP and 2,4,6TCP to metabolites with less chloride groups and by the detection of chlorophenol RD cprA gene fragments in dechlorinating cultures. PCR amplified cprA gene fragments were cloned and sequenced and found to cluster with the cprA/pceA type genes of Dehalobacter restrictus.

Chlorophenols (CPs) are among the most significant environmental concerns worldwide, which pose a serious threat to global water safety and human health. Herein, a novel electrocatalytic hydrogenation (ECH) pathway was proposed for the detoxification of CPs, where both the cleavage of C−Cl bond and hydrogenation of phenol ring take place. Employing a fibrous Ru/TiO 2 electrode (f-Ru/TiO 2) with massive microchannels, we achieved over 99.8% removal of 1 mM 4-chlorophenol (4-CP) within 60 min, with a corresponding kinetic constant of 0.101 min−1. The toxic 4-CP was completely transformed into cyclohexanol, which possesses almost no biotoxicity and could be rapidly recovered from treated water. The ECH system exhibited high 4-CP removal efficiencies at different pH conditions (3−11). Besides, a 4-CP removal efficiency of over 99.1% was achieved even at a remarkably high concentration (10 mM). Mechanism analysis confirms that direct electron transfer dominates the ECH process, while the contribution of atomic hydrogen (H*) is less prominent. Overall, this study demonstrates an inspiring ECH approach with enhanced pollutants diffusion and electron transfer for not only the detoxification of but also resource recovery from chlorophenol wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, pure sepiolite and sepiolite modified by nitric acid (HNO3), ethylenediaminetetraacetic acid (EDTA) and hexadecyltrimethyl-ammonium (HDTMA) were used ad adsorbents. The changes on the surface were studied by IR spectroscopy. The adsorption of solutions of phenol and phenol derivatives in pure ethanol on these adsorbents were examined by means of gas chromatography. It was found that the adsorption capacities of the clay–organic complexes (sepiolite–EDTA and sepiolite–HDTMA) were higher than those of pure sepiolite and sepiolite–HNO3.

In this work, pure sepiolite and sepiolite modified by nitric acid (HNO3), ethylenediaminetetraacetic acid (EDTA) and hexadecyltrimethylammonium (HDTMA) were used ad adsorbents. The changes on the surface were studied by IR spectroscopy. The adsorption of solutions of phenol and phenol derivatives in pure ethanol on these adsorbents were examined by means of gas chromatography. It was found that the adsorption capacities of the clay-organic complexes (sepiolite-EDTA and sepiolite- HDTMA) were higher than those of pure sepiolite and sepiolite-HNO3.

The article has assessed current losses of porosity of activated carbon due to the existence of microbial activity in the fixed sorbent bed during the removal of 2-chlorophenol from water. Non-target losses of vacant porosity of carbon increased depending on the time of functioning the biological system. At the end of the second year the content of bioproducts in spent pores constituted 75-85%. [ABSTRACT FROM AUTHOR]

Chlorophenols, typically 4-chlorophenols are highly toxic and non-biodegradable organic contaminants which pose serious threat to the environment, particularly when released into aqueous medium. The removal of these pollutants by efficient method has received worldwide concern in recent past. A new Fe 3 O 4 –Cr 2 O 3 magnetic nanocomposite was synthesized by wet chemical method under ultrasonic irradiation. Microstructure and morphology of the nanocomposite were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and a transmission electron microscope (TEM). Magnetic and optical properties were studied by a vibrating sample magnetometer (VSM) and an ultraviolet–visible (UV–Vis) spectrophotometer respectively. The magnetic nanocomposite (MNC) was used as photocatalyst for effective decomposition of 4-chlorophenol in water under ultraviolet (UV) irradiation. [ABSTRACT FROM AUTHOR]

In this study, macroporous poly(glycidyl methacrylate- co -ethylene glycol dimethacrylate) was synthesized by suspension copolymerization, functionalized by ring-opening reaction of the pendant epoxy groups with diethylene triamine and used for immobilization of Pd(II) ions from chloride and nitrate solutions under batch experimental condition. The amino-functionalized sample and samples with immobilized Pd(II) ions were characterized by Fourier transform infrared spectroscopy (FTIR) analysis and scanning energy-dispersive X-ray spectroscopy (SEM-EDX). The electrochemical behavior of electrodes composed of synthesized samples was tested in 0.1 M H 2 SO 4 by means of cyclic voltammetry (CV). The shape of recorded CV showed dependence on the type of Pd-salt used for Pd immobilization. The reaction of oxidation of 4-chlorophenol (4-CP) from 0.1 M H 2 SO 4 at investigated samples was also studied. Electrooxidation of 4-CP resulted in passivation and formation of reversible hydroquinone/benzoquinone on both investigated electrodes, although hydroquinone/benzoquinone formation was more pronounced on Pd immobilized from nitrite solution. [ABSTRACT FROM AUTHOR]

In this work, bimetallic zerovalent iron-silver nanoparticles (NZVI-Ag) immobilized in calcium alginate beads were prepared and characterized. This material was tested as catalyst in the dechlorination and oxidation of 4-chlorophenol (CP-4). The bimetallic nanoparticles showed average size and BET surface area around 80 nm and 22 m 2 g −1 , respectively, with morphology and crystallinity typical of nanometric metallic iron. 4-CP dechlorination was more efficient at pH 3 than at pH 5 and at the former was completed in 30 min. Further addition of H 2 O 2 allowed high TOC reduction, quite similar to the obtained with the bare metallic nanoparticles but with lower metal leaching. [ABSTRACT FROM AUTHOR]

Cellulose-based microporous carbon fibers (CFs) were evaluated for the adsorption of 2-Chlorophenol (CP), 2,4-Dichlorophenol (DCP), and 2,4,6-Trichlorophenol (TCP), which are persistent organic pollutants in wastewater. CFs with different surface area values were prepared by using ZnCl as a chemical activator, and the samples were characterized by BET, FTIR, SEM, PALS, Zeta potential, and pH titration analysis. The point of zero charge values for CF-1, CF-2, and CF-3 were found as 8.14, 6.79, and 7.01, respectively. The surface area of CFs were determined as 454 m/g (CF-1), 760 m/g (CF-2), and 1217 m/g (CF-3), and PALS measurements at ambient temperature and vacuum indicated the effective pore diameter of about 0.6 nm for all samples. The adsorption of chlorophenols was examined at different solution pH, temperature, and contact time. At the optimum pH of 6.0, the DCP adsorption capacities of CFs, namely, CF-1, CF-2, and CF-3 were calculated as 29.27, 229.81, and 244.09 mg/g, respectively. The adsorption capacity of the CF-3 sample was found to be an ideal adsorbent for CPs removal from aqueous solutions. A comparison of the adsorption kinetic data was best described by the pseudo second-order and particle diffusion models. For the CF-2 sample, the initial sorption rates of CP, DCP, and TCP were found in the increasing order as 2.084, 32.23, and 43.63 mg/g min. Similar order of the sorption rates were also observed for CF-1 and CF-3 samples. The obtained results demonstrated the fact that among the CP homologues, TCP showed both a higher affinity and a higher diffusion rate for all CFs. The adsorption process was found to be exothermic, and the entropy values were positive, depicting that CPs were randomly distributed at the solid/solution interface. [ABSTRACT FROM AUTHOR]

The article has investigated regularities of the process of transformation of active carbon into biologically activated carbon in the course of an effective filtration purification of water of 2-chlorophenol. In exploitation of active carbon for more than two years the contribution of the adsorption and biodestructive components to the removal of the target component was marked off. It has been shown that more than 80-85% of chlorophenol is removed biologically after four-five months from the beginning of the process. [ABSTRACT FROM AUTHOR]

Pentachlorophenol (PCP) is a toxic compound which is widely used as a wood preservative product and general biocide. It is persistent in the environment and has been classified as a persistent organic pollutant to be reclaimed in many countries. Fungal bioremediation is an emerging approach to rehabilitating areas fouled by recalcitrant xenobiotics. In the present study, we isolated two fungal strains from an artificially PCP-contaminated soil during a long-term bioremediation study and evaluated their potential as bioremediation agents in depletion and detoxification of PCP in soil microcosms. The two fungal strains were identified as: Byssochlamys nivea (Westling, 1909) and Scopulariopsis brumptii (Salvanet-Duval, 1935). PCP removal and toxicity were examined during 28 days of incubation. Bioaugmented microcosms revealed a 60% and 62% PCP removal by B. nivea and S. brumptii , respectively. Co-inoculation of B. nivea and S. brumptii showed a synergetic effect on PCP removal resulting in 95% and 80% PCP decrease when initial concentrations were 12.5 and 25 mg kg −1 , respectively. Detoxification in bioaugmented soil and the efficient role of fungi in the rehabilitation of PCP contaminated soil were experimentally proven by toxicity assays. A decrease in inhibition of bioluminescence of Escherichia coli HB101 pUCD607 and an increase of germination index of mustard ( Brassica alba ) seeds were observed in the decontaminated soils. [ABSTRACT FROM AUTHOR]

Electrostatic interactions occurring in the immediate environment of the metal center in native enzymes influence the charge distribution and electron donation ability, regulating activity. Herein, using an iron-porphyrin biomimetic complex, we have investigated the effect of the protonation state of the axial imidazole on the catalytic oxidation of pentachlorophenol. We show that the catalytic efficiency is drastically affected by the anionic state of the axial ligand. The chemical events occurring during the catalytic cycle were monitored by a detailed analytical study. EPR, UV–Vis and low temperature UV–Vis together with theoretical DFT and TD-DFT calculations provide evidence that deprotonation of the axial imidazole leads to increased electron donation ability to the central metal, enhancing the formation of ferryl species. Imidazole favored the formation of a pure porphyrin-radical model at the high-valent Fe IV OPor + state while imidazolate presented a significant axial ligand-radical character. The theoretical calculations suggest that the enhanced catalytic activity of the deprotonated conformation is attributed to the increased electron donation ability, favoring the formation of the ferryl species and suggesting that the “push” effect prevails over the “pull” effect. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation of 4-chlorophenol (CP) was investigated (in terms of chemical oxygen demand (COD) and CP removal efficiencies) by using a dimensionally stable anode (DSA) namely ruthenium oxide coated titanium (Ti/RuO 2 ) electrode. Effect of process conditions such as current density ( j ), electrolyte concentration ( m ), initial pH (pH o ), time ( t ) and initial CP concentration ( C o ) has been studied. Current efficiency (CE) and specific energy consumption (SEC) were also measured. Gas chromatograph-mass spectrometry (GC/MS) analysis was used to understand the CP mineralization mechanism which has been established on the basis of intermediates identified such as benzoquinone, hydroquinone and organic acids. Reaction kinetics was expressed by pseudo-first order kinetic model. Maximum COD removal efficiency of 96.7% and CP removal efficiency of 97.2%, respectively, was observed at j = 222.22 A/m 2 , t = 180 min, pH o = 5.2 and m = 400 mg/l with SEC = 655 kWh/kg COD. Operating cost based on the studies performed on laboratory scale EC reactor has been calculated and compared with those reported for other pollutants degradation. [ABSTRACT FROM AUTHOR]

Hydrodechlorination (HDC) of chlorinated pollutants in water such as 4-chlorophenol (4-CP) and 4-chloroaniline (4-CA) was carried out with catalysts based on Pt and Ir supported pillared clays. Almost complete dechlorination was achieved at short reaction time under mild operation conditions with the Pt catalyst. The incorporation of cerium oxide to the Pt and Ir catalysts (PtCe and IrCe catalysts, respectively) led to a higher dispersion than that of the monometallic ones. The catalyst loaded with Pt showed low reaction rates and conversion while the one modified with increasing amounts of cerium oxide was highly active for conversion of the chlorinated pollutants. On the contrary, the IrCe catalysts were found poorly active due to partial coverage of Ir crystallites by cerium oxide. [ABSTRACT FROM AUTHOR]

Binary metal oxides with different degrees of covalent/ionic character of the oxygen-metal bond are tested as a partial coating of glassy carbon electrode surfaces. The electrocatalytic and antifouling properties of the resulting bicomponent electrode systems are analysed in view of possible applications in different fields of electrochemistry, such as electroremediation and electroanalysis. Based on the performance with respect to oxidation of ascorbic acid, as to sensitivity, repeatability of the responses, and activation of electrocatalytic oxidation, CeO has been preferred. This same electrode system has been further studied in respect to a trickier electrochemical process, namely the anodic oxidation of a chlorophenol derivative, which induces massive passivation of bare electrode surfaces. The effectiveness of the bicomponent electrode system in anodic oxidation of 2,4,6-trichlorophenol has been ascertained, over a wide range of concentrations, by comparison with pure glassy carbon surfaces. [ABSTRACT FROM AUTHOR]

A simple online headspace solid-phase microextraction (HS-SPME) coupled with the gas chromatography-mass spectrometry (GC-MS) method was developed for simultaneous determination of trace amounts of nine estrogenic odorant alkylphenols and chlorophenols and their derivatives in water samples. The extraction conditions of HS-SPME were optimized including fiber selection, extraction temperature, extraction time, and salt concentration. Results showed that divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber was the most appropriate one among the three selected commercial fibers, and the optimal extraction temperature, time, and salt concentration were 70 °C, 30 min, and 0.25 g/mL, respectively. The developed method was validated and showed good linearity ( R > 0.989), low limit of detection (LOD, 0.002-0.5 μg/L), and excellent recoveries (76-126 %) with low relative standard deviation (RSD, 0.7-12.9 %). The developed method was finally applied to two surface water samples and some of these target compounds were detected. All these detected compounds were below their odor thresholds, except for 2,4,6-TCAS and 2,4,6-TBAS wherein their concentrations were near their odor thresholds. However, in the two surface water samples, these detected compounds contributed to a certain amount of estrogenicity, which seemed to suggest that more attention should be paid to the issue of estrogenicity rather than to the odor problem. [ABSTRACT FROM AUTHOR]

Sorption of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) on a range of dealuminated zeolites were investigated to understand the mechanism of their sorption on microporous minerals, while the influence of common metal cations, solution pH, and humic acid was also studied. Sorption of chlorophenols was found to increase with the hydrophobicity of the sorbates and that of the microporous minerals, indicating the important role of hydrophobic interactions, while sorption was also stronger in the micropores of narrower sizes because of greater enhancement of the dispersion interactions. The presence of metal cations could enhance chlorophenol sorption due to the additional electrostatic attraction between metal cations exchanged into the mineral micropores and the chlorophenolates, and this effect was apparent on the mineral sorbent with a high density of surface cations (2.62 sites/nm) in its micropores. Under circum-neutral or acidic conditions, neutral chlorophenol molecules adsorbed into the hydrophobic micropores through displacing the 'loosely bound' water molecules, while their sorption was negligible under moderately alkaline conditions due to electrostatic repulsion between the negatively charged zeolite framework and anionic chlorophenolates. The influence of humic acid on sorption of chlorophenols on dealuminated Y zeolites suggests that its molecules did not block the micropores but created a secondary sorption sites by forming a 'coating layer' on the external surface of the zeolites. These mechanistic insights could help better understand the interactions of ionizable chlorophenols and metal cations in mineral micropores and guide the selection and design of reusable microporous mineral sorbents for sorptive removal of chlorophenols from aqueous stream. [ABSTRACT FROM AUTHOR]

The removal of eight chlorophenols (2-CP, 3-CP, 4-CP, 2,3-DCP, 2,4-DCP, 2,5-DCP, 2,6-DCP and 2,4,6-TCP) using adsorption on activated carbon and adsorption in the presence of hydrogen peroxide was investigated. The influence of the pH, activated carbon dosage and hydrogen peroxide concentration were studied. The effects of the chlorine atom position and the chlorine content in the chlorophenol molecules on their degradation were also studied. The results revealed that the integration of the activated carbon and HO treatment was more effective for the removal of the chlorophenols than using the activated carbon alone. The adsorption kinetics and adsorption efficiency increased with the increasing substitution of chlorine on the aromatic ring. The degradation rate and degradation efficiency of the chlorophenols using the activated carbon integrated with HO decreased with the increasing chlorine atoms in the molecule. The combination of the activated carbon with hydrogen peroxide may significantly enhance the process and could offer an interesting alternative in wastewater treatment. [ABSTRACT FROM AUTHOR]

Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260–791. Limits of qualification ranged from 5.5 to 16.0 ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl − ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry. [ABSTRACT FROM AUTHOR]

Regeneration of loaded adsorbents is a key step for the sustainability of an adsorption process. In this study, ozone was applied to regenerate a synthetic zeolite for the adsorption of trichlorophenol (TCP) as an organic model pollutant. Three initial concentrations of TCP in water phase were used in adsorption tests. After the equilibrium, zeolite loaded different amounts of TCP was dried and then regenerated with ozone gas. It was found that the adsorption capacity of zeolite was increased through three regeneration cycles. However, the adsorption kinetics was compromised after the regeneration with slightly declined 2nd order reaction constants. The ozone demand for the regeneration was highly dependent on the TCP mass loaded onto the zeolite. It was estimated that the mass ratio of ozone to TCP was 1.2 ± 0.3 g O 3 /g TCP. [ABSTRACT FROM AUTHOR]

The kinetics of the oxidation of chlorophenols (CPs) by potassium permanganate was studied in the present study, along with the changes in oxidant dosage, pH, temperature, and real water matrices. The reactions between permanganate and three kinds of CPs, i.e. 4-chlorophenol (4-MCP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP), are second order overall and first-order with respect to each reactant. The degradation rates of the CPs increase with increasing permanganate dosage or temperature. pH plays an important role during permanganate oxidation. With the increase in pH from 4.0 to 10.0, the reaction rates of 4-MCP and 2,4-DCP decrease first and then increase, and finally decrease rapidly when pH > pKa, while the rates of 2,4,6-TCP decrease continuously. The degradation rates of the CPs are obviously higher in real water than in pure water. The reaction rate follows the order of 2,4,6-TCP > 2,4-DCP > 4-MCP under acidic conditions, and follows the reverse order under alkaline conditions in both pure water and real water. [ABSTRACT FROM AUTHOR]

BACKGROUND Electrolysis with an iron anode is a novel way to provide ferrous activators for chemical oxidation. The objective of this study is to evaluate the performance of peroxymonosulfate ( PMS) for chlorophenol destruction when compared with H2O2 and persulfate ( PS), and to see whether the electrolysis mode facilitates the buildup of conditions that favor the activation of PMS and removal of chlorophenols. RESULTS Ferrous species can effectively activate the PMS over a wide pH range. In comparison with H2O2 and PS, PMS is less sensitive to the solution's pH and possesses stronger oxidation capability at alkaline pHs. The optimal molar ratio of PMS to Fe( II) activator is 1:1 for the destruction of 2,4-dichlorophenol (2,4- DCP). The column experiments show that an acidic zone developed downstream from the anode is favorable to maintain ferrous ions and subsequent activation of PMS. The reactivity of the PMS can be manipulated by varying the electrical currents, and the process demonstrates effectiveness for treating organic contaminants. 2,4- DCP contaminated groundwater shows decreased biotoxicity after the chemical oxidation process without considering the residual PMS. CONCLUSIONS Iron electrolysis-assisted peroxymonosulfate chemical oxidation can effectively treat the 2,4-dichlorophenol and mixtures of organic contaminants. This process can be engineered as an in situ chemical oxidation method for groundwater remediation. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This work was the first step of a study initiated by the FFT (Fédération Française de la Tonnellerie) to review the different aspects of the oak wood contamination, and especially contamination by chlorophenols and chloroanisoles. This paper deals with the precision of chlorophenols and chloroanisoles measurement in cooperage oak woods. The analytical methods used were those developed and single validated by the 4 laboratories that did this work. Material was obtained by adding substances to sawdust and making dilution between supplemented sawdust and blank one. Thus, material was homogenous and has a theoretic level. Recovery values for chlorophenols were between 70 % and 80 %, except one, for the lowest PCP's level (theoretic 7.5 ng/g), which was 95 %. For chloroanisoles, recovery values varied from 50 % for the highest levels to more than 100 % for the lowest levels. Measured reproducibility, expressed in variation coefficient of the standard deviation, was about 25 % for TCP and PCP, 45 % for TeCP, TCA and TeCA and more than 50 % for PCA. For TCP, PCP, TCA and TeCA, despite the use of different methods, these values are of the same order as those given by the Horwitz formula. These values may help to compare results and to build a decision rule of the conformity of the oak wood. The heterogeneousness of the material is another source of the final result variability. This last source was not quantified in this work.