Concentrations Of Chlorophenols Research Articles

Optimization of 4-chlorophenol decomposition by H2O2 activate catalytic magnetic iron oxide an activated carbon carrier

Wastewater from chemical plants that produce pesticides always carries a large amount of organic matter that is difficult to decompose. One of them is the compound 4-chlorophenol, which has difficult-to-decompose properties, is durable in the environment, and is also listed in the group of substances that are likely to cause cancer in humans. In this study, the 4-chlorophenol compound was treated with heterogeneous Fenton by H2O2 activated by magnetic iron oxide nanoparticles on activated carbon. Magnetic iron oxide nanoparticles were successfully synthesized and mounted on activated carbon 10-15 nm in size with material surface morphological parameters such as specific surface area 330.28 cm2/g; total pore volume 0.16 cm3/g; magnetization 8.19 emu/g. The optimization of the 4-chlorophenols decomposition reaction with pH parameters, the content of catalytic materials, and the initial concentration of 4-chlorophenol is carried out using the Box-Behnken Design. The results showed that the removal efficiency of 4-chlorophenol was 96.5% achieved with optimum parameters pH 2.9; catalytic concentration 0.32 g/L; initial concentration of 4-chlorophenol 92.3 mg/L. The results of the study show the efficiency of the decomposition of an organic compound using magnetic activated carbon.

Ni-Zn/CeO2 nanocomposites for enhanced adsorptive removal of 4-chlorophenol.

Chlorophenols are one of the major organic pollutants responsible for the contamination of water bodies. This study explores the application of Ni-Zn/CeO2 nanocomposites, synthesized via the aqueous co-precipitation method, as effective adsorbents for the 4-chlorophenol removal from aqueous solutions. The nanocomposites' chemical and structural characteristics were assessed using different physical characterization methods, viz. X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential, using a Box-Behnken design within response surface methodology, optimal conditions of pH 3, temperature 20 °C, contact time 120 min, adsorbent dosage 0.05 g, and 4-chlorophenol concentration 50 ppm are identified. Among the nanocomposites tested, NZC 20:10:70, with 20% Ni and 10% Zn, achieves enhanced performance, removing 99.1% of 4-chlorophenol within 2 h. Adsorption kinetics follow the pseudo-second-order model and equilibrium data fit the Freundlich isotherm. Thermodynamic analysis indicates an exothermic and spontaneous process. The adsorption capacity of NZC 20:10:70 shows significant enhancement, growing from 19.85 mg/g at 10 ppm to 96.33 mg/g at 50 ppm initial concentration. Physical characterization confirms NZC 20:10:70's superior properties, including a high surface area of 118.471 m2/g. Evaluating economic viability, NZC 20:10:70 demonstrates robust reusability, retaining 85% efficiency over eight regeneration cycles. These results highlight NZC 20:10:70 as a promising adsorbent for effective and sustainable chlorophenol removal in water treatment.

Magnetic multi-template molecularly imprinted polymers for selective simultaneous extraction of chlorophenols followed by determination using HPLC

Magnetic multi-template molecularly imprinted polymers (M-mt-MIPs) were successfully synthesized by surface imprinting and multi-template imprinting strategy, using polydopamine coated magnetic multi-walled carbon nanotubes as supporting materials, five typical chlorophenols (CPs) as templates, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker. Compared to non-imprinted polymers (NIPs), the as-prepared M-mt-MIPs showed high adsorption capacity (32.58‒80.63 mg g−1), rapid mass transfer and specific selectivity for the five targeted CPs, which were applied as magnetic solid-phase extraction (MSPE) adsorbents. Parameters affecting MSPE efficiency were detailed investigated, such as adsorbents dosage, sample pH, extraction time, type and volume of desorption solvent and salt effect. Combined with HPLC-DAD, a simple, rapid and sensitive method was established, showing good linearity (2‒200 μg L−1), low limits of detection (0.32‒0.49 μg L−1), and high enrichment factors (35.2‒108). The developed M-mt-MIPs-MSPE-HPLC method was applied to enrich and determine CPs in tannery wastewater, wet-blue and crust leather, and satisfactory spiking recoveries were attained in the range of 73.95‒109.7% with relative standard deviations (RSDs) of 2.13–8.48%. This study provided a new alternative material and method to rapid simultaneously extract and analyze low concentration of typical CPs in complicated matrices.

Synthesis of activated carbon/magnetite nanocatalyst for sono-Fenton-like degradation process of 4-chlorophenol in an ultrasonic reactor and optimization using response surface method

Effective removal of 4-chlorophenol, a toxic and persistent organic pollutant, from wastewater is of utmost importance for environmental preservation and human well-being. The aim of this study is to design a new reactor for the quasi-Fenton process to increase the degradation efficiency of 4-chlorophenol using ultrasonic waves. For this purpose, activated carbon/magnetite nanocatalyst was synthesized using active carbon obtained from used tires and Fe3O4 nanoparticles prepared by the chemical coprecipitation method. The characterization of the active carbon/magnetite nanocatalyst showed a specific surface area of 172.46 m2g−1, and the size of the nanocatalyst was 10 nm. In addition, FTIR, EDX and XRD analyses were also investigated to identify the nanocatalyst. Evaluation of mechanical and chemical resistance confirmed the stability of the nanocatalyst. The degradation process of 4-chlorophenol was optimized using the RSM method. The experimental findings indicated that the optimal operating conditions for maximizing 4-chlorophenol removal efficiency were found to be pH 3, temperature 42 °C, nanocatalyst dose 2 gL−1, hydrogen peroxide concentration 25.58 mM ultrasonic power 320 W, and reaction time of 78 min. The validity of these optimal conditions was further confirmed through real-world experiments, resulting in remarkable removal efficiencies of 97.32 % and 93.47 % for 4-chlorophenol concentrations of 250 and 500 mgL−1, respectively.

Multifunctional polysaccharide structure as green adsorbent for efficient removal and preconcentration of chlorophenols from the aqueous medium: experimental and modeling approaches.

The growing concerns about water pollution have prompted researchers to explore new materials for remediating and purifying it. In recent years, there has been a focus on polysaccharides as eco-friendly polymers that exhibit high efficiency in removing chlorophenols from waste water. This study aims to develop a trifunctional polysaccharide structure using a biodegradable matrix. The chitosan/alginate-polyethyleneimine-phenyl-phosphonamidic acid (CHIT/ALG-PEIPPAA) matrix was employed for removing chlorophenols from water. The study carefully examined the impact of various physicochemical parameters such as pH, reaction time, chlorophenols concentration, temperature, and ionic strength to determine the optimal conditions for the adsorption process. Several techniques were used to confirm the morphology, physicochemical properties, structure, and functionalization of the polymer. Scanning electron microscopy (SEM) images revealed a heterogeneous morphology with agglomerates of different particle sizes, ranging from a few micrometers with irregular shapes. The FTIR spectrum and zeta potential characterization indicated the presence of hydrophilic groups and a highly positive charge (around 31.4 mV) on the surface of the CHIT/ALG-PEIPPAA adsorbent. The optimal pH for chlorophenols removal was found to be approximately 4.4. The kinetic data supported the pseudo-second-order kinetic model, which accurately described the adsorption behavior of both chlorophenol molecules. The fitting of the isotherm analysis revealed that the Langmuir model provided a better representation of the adsorption process. The maximum adsorption capacities for 4-chlorophenol and 2,4-chlorophenol were approximately 118 mg.g-1 and 249 mg.g-1, respectively. The calculated thermodynamic functions confirmed an exothermic and spontaneous adsorption process for chlorophenols, with ∆H values of -6.98 kJ.mol-1 and -2.74 kJ.mol-1 for 4-chlorophenol and 2,4-chlorophenol, respectively. The regeneration process of the CHIT/ALG-PEIPPAA adsorbent showed higher efficacy in the presence of hydrochloric acid (2.0 mol.L-1), resulting in up to 91% desorption of chlorophenols. The CHIT/ALG-PEIPPAA adsorbent demonstrated good reusability after regeneration, with only a slight decrease in extraction efficiency: 34.63% for 4-chlorophenol and 79.03% for 2,4-chlorophenol, under the same optimal conditions as the initial adsorption cycle.

Metabolic insights into the interaction between nitrogen removal and 4–chlorophenol reduction of anammox consortia

The response characteristic and performance stabilization of anammox process under the stress of the potential organic pollutants support the application of ammonia–nitrogen wastewater treatment. In the present study, nitrogen removal performance was significantly suppressed with the addition of 4–chlorophenol. The activity of anammox process was inhibited by 14.23% (0.1 mg/L), 20.54% (1 mg/L) and 78.15% (10 mg/L), respectively. Metagenomic analysis revealed a significant decrease in the abundance of KEGG pathways associated with carbohydrate and amino acid metabolism with increasing 4–chlorophenol concentration. Metabolic pathway profiles suggest that putrescine is down–regulated at high 4–chlorophenol stress due to inhibition of nitrogen metabolism processes, while it is up–regulated to reduce oxidative damage. In addition, the presence of 4–chlorophenol induced an enhancement of EPS and bacterial debris decomposition, and a partial conversion of 4–chlorophenol to p–nitrophenol. This study unravels the mechanism of effect on anammox consortia in response to 4–CP, which could provide supplementary to facilitate its full-scale application.

4-Chlorophenol adsorption from water solutions by activated carbon functionalized with amine groups: response surface method and artificial neural networks

4-Chlorophenol pollution is a significant environmental concern. In this study, powdered activated carbon modified with amine groups is synthesized and investigated its efficiency in removing 4-chlorophenols from aqueous environments. Response surface methodology (RSM) and central composite design (CCD) were used to investigate the effect of different parameters, including pH, contact time, adsorbent dosage, and initial 4-chlorophenol concentration, on 4-chlorophenol removal efficiency. The RSM-CCD approach was implemented in R software to design and analyze the experiments. The statistical analysis of variance (ANOVA) was used to describe the roles of effecting parameters on response. Isotherm and kinetic studies were done with three Langmuir, Freundlich, and Temkin isotherm models and four pseudo-first-order, pseudo-second-order, Elovich, and intraparticle kinetic models in both linear and non-linear forms. The synthesized adsorbent was characterized using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses. The results showed that the synthesized modified activated carbon had a maximum adsorption capacity of 316.1 mg/g and exhibited high efficiency in removing 4-chlorophenols. The optimal conditions for the highest removal efficiency were an adsorbent dosage of 0.55 g/L, contact time of 35 min, initial concentration of 4-chlorophenol of 110 mg/L, and pH of 3. The thermodynamic study indicated that the adsorption process was exothermic and spontaneous. The synthesized adsorbent also showed excellent reusability even after five successive cycles. These findings demonstrate the potential of modified activated carbon as an effective method for removing 4-chlorophenols from aqueous environments and contributing to developing sustainable and efficient water treatment technologies.

Occurrence, distribution, and risk assessment of halogenated organic pollutants (HOPs) in marine fish muscle: The case study of Vietnam

Halogenated organic pollutants (HOPs), including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and chlorophenols (CPs), were identified in three marine fish species in Vietnam. Total PCBs, OCPs, and CPs concentrations ranged from 4.5 to 711.6 ng g−1 lipid weight (lw), 69.9–2360 ng g−1 lw, and 208.1–3941.2 ng g−1 lw, respectively. CPs were the most frequently detected pollutants in the marine environment of Vietnam of the three HOPs studied, followed by OCPs and PCBs. There are significant differences in HOPs between three types of seafood in Vietnam, including yellowstripe scad, Indian mackerel, and silver pomfret in this study. Notably, the types and amounts of HOPs found in the fish were differently influenced by the economic and industrial activities of the sampled areas. Despite these findings, the consumption of HOP-contaminated fish from the study areas was found not to pose any significant health risks to Vietnam's coastal population.

СЕНСОРНЫЙ КОМПОЗИТ НАНОВОЛОКНА γ-Al2O3 / НАНОАЛМАЗЫ / Cu2+ С УВЕЛИЧЕННОЙ КАТАЛИТИЧЕСКОЙ АКТИВНОСТЬЮ ДЛЯ ДЕТЕКЦИИ ФЕНОЛОВ В ВОДНОЙ СРЕДЕ

A functionalized composite γ-Al2O3 nanofibers / nanodiamond / Cu2+ with improved sensor properties for the detection of phenols in an aqueous medium was obtained by chemical modification with copper ions of a new composite material based on alumina nanofibers and nanodiamonds. The chemical modification of the composite made it possible to increase its catalytic activity more than twice in the co-oxidation of phenols with 4-aminoantipyrine in the presence of H2O2. The obtained effect enabled to reduce the threshold of the minimum detectable concentration of analytes by half when they were tested using a functionalized composite. What was demonstrated by the example of the detection of phenol and 4-chlorophenol. It was shown that the obtained composite provides a linear response in a wide range of concentrations of phenol (0.25–100 μM) and 4-chlorophenol (0.5–25 μM). It is found that the adsorbed Cu2+ ions are firmly bound to composite surface, are not desorbed, and are not inactivated by co-oxidation reagents during repeated use of the composite. The applicability of a functionalized composite as a reusable sensor was shown in model experiments in the course of sequential multiple testing of phenol in aqueous samples. Comparative studies of the kinetics and isotherms of adsorption of Cu2+ ions on a composite material and an alumina matrix, and estimation their sorption capacity were also carried out in the work.

An Evaluation of the Kinetic Properties Controlling the Combined Chemical and Biological Treatment of Toxic Recalcitrant Organic Compounds from Aqueous Solution

Due to their high toxicity, propensity for cancer, teratogenicity, mutagenicity, and genotoxicity, hazardous water-soluble phenolic compounds must be controlled immediately. In this study, a model was created to simulate the degradation of harmful recalcitrant organic compounds in a combined chemical and biological treatment system. The parameter estimations with inhibition coefficient (Haldane model) and without inhibition coefficient (Michaelis-Menten model) were assessed over a wide range of initial concentrations using the Monod-like model. The kinetic parameters were optimized using AQUASIM 2.0 software. At a 50 mg·L−1 feed concentration of 4-chlorophenol, removal efficiencies of more than 98% were attained under these circumstances. The primary kinetic parameters were identified and their values models were validated using the fitted parameter values that reached a good degree of agreement (R2 = 0.998). We may better comprehend and make use of the complex phenolic compounds’ biodegradation processes, such as progress optimization and scale-up, by understanding the mechanisms of substrate interaction and the new kinetic models that have been provided in this work.

Photochemical transformations of 2, 6-dichlorophenol and 2-chlorophenol with superoxide ions in the atmospheric aqueous phase

The possible photochemical transformation pathways of chlorophenols (2, 6-dichlorophenol and 2-chlorophenol) with superoxide anion radical (O2·−) were studied by steady-state irradiation and 355 nm laser flash photolysis technique. O2·− was generated by irradiating riboflavin O2-saturated solution with an UVA light (maximum at 365 nm). The steady-state experimental results suggested that the transformation efficiency of chlorophenols improved with the increase of the initial riboflavin concentration and solution initial pH value, while the increase of chlorophenols concentration would inhibit the photochemical reaction. The second-order rate constant of the reaction of O2·− with 2, 6-DCP phenoxyl radical (2, 6-DCP·) and 2-CP phenoxyl radical (2-CP·) were determined as (8.39 ± 0.99) × 109 L mol−1 s−1 and (5.17 ± 0.68) × 109 L mol−1 s−1 by laser flash photolysis techniques, respectively. The transformation of chlorophenols was accompanied by the formation of Cl− induced by superoxide radicals after the mixed riboflavin and chlorophenols solution with UVA irradiation. The main conversion products of the reaction between 2, 6-DCP and O2·− were identified by GC-MS, as 2-chlorophenol, 2, 6-dichloro-1, 4-benzoquinone, 2, 6-dichloro-hydroquinone and 3-chlorocatechol, while 2-CP with O2·− was 2-chloro-1, 4-benzoquinone, 2-chlorohydroquinone and phenol, respectively. The transformation pathways of 2, 6-DCP and 2-CP with O2·− were also proposed.

Integration of in-situ chemical oxidation and permeable reactive barrier for the removal of chlorophenols by copper oxide activated peroxydisulfate

In-situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) have been used in field practices for contaminated groundwater remediation. In this lab-scale study, a novel system integrating ISCO and PRB using peroxydisulfate (PDS) as the oxidant and copper oxide (CuO) as the reactive barrier material was developed for the removal of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP). The influences of chlorophenol concentration and flow rate on the system performance were first evaluated using synthetic solutions. The removal efficiencies of target chlorophenols were greater than 90% when sufficient PDS was supplied ([PDS]/[chlorophenol]>1). It was also found that the removal efficiencies decreased with the increasing chlorophenol concentrations (10–150 μM) and flow rates (1.8–14.4 mL/min). When three real groundwaters were employed, the removal efficiencies of 2,4-DCP and 2,4,6-TCP slightly reduced to 90% and 85%, respectively. For PCP, the removal efficiency dropped to 20% in two groundwaters with relatively high levels of alkalinity. The influences of pH and TOC were found to be insignificant for the range investigated (pH 6.5–8.7 and TOC = 0.4–1.5 mgC/L). The reduced removal efficiency could be due to the formation of weaker radicals and the stronger competition between bicarbonate ions and PDS for the activation sites on the CuO surfaces.

Removal of Cr(vi) and p-chlorophenol and generation of electricity using constructed wetland-microbial fuel cells based on Leersia hexandra Swartz: p-chlorophenol concentration and hydraulic retention time effects.

Heavy metals and phenolic compounds existing in polluted wastewater are a threat to the environment and human safety. A downflow Leersia hexandra Swartz constructed wetland-microbial fuel cell (DLCW–MFC) was designed to treat polluted wastewater containing Cr(vi) and p-chlorophenol (4-CP). To determine the effect of 4-CP concentration and hydraulic retention time (HRT) on the performance of the DLCW–MFC system, the wastewater purification, electricity generation, electrochemical performance, and L. hexandra growth status were studied. Addition of 17.9 mg L−1 4-CP improved the power density (72.04 mW m−2) and the charge transfer capacity (exchange current, 4.72 × 10−3 A) of DLCW–MFC. The removal rates of Cr(vi) and 4-CP at a 4-CP concentration of 17.9 mg L−1 were 98.8% and 38.1%, respectively. The Cr content in L. hexandra was 17.66 mg/10 plants. However, a 4-CP concentration of 35.7 mg L−1 inhibited the removal of Cr(vi) and the growth of L. hexandra, and decreased the electricity generation (2.5 mW m−2) as well as exchange current (1.21 × 10−3 A) of DLCW–MFC. An increase in power density and removal of Cr(vi) and 4-CP, along with an enhanced transport coefficient of L. hexandra, was observed with HRT. At an optimal HRT of 6.5 d, the power density, coulomb efficiency, and exchange current of DLCW–MFC were 72.25 mW m−2, 2.38%, and 4.99 × 10−3 A, respectively. The removal rates of Cr(vi) and 4-CP were 99.0% and 78.6%, respectively. The Cr content and transport coefficient of L. hexandra were 4.56 mg/10 plants and 0.451, respectively. Thus, DLCW–MFC is a promising technology that can be used to detoxify polluted wastewater containing composite mixtures and synchronously generate electricity.

A robust biocatalyst based on laccase immobilized superparamagnetic Fe3O4@SiO2–NH2 nanoparticles and its application for degradation of chlorophenols

The presence of chlorophenols in water and wastewater is considered a serious environmental issue. To eliminate these micropollutants, biodegradation of chlorophenols using enzyme-nanoparticle conjugated biocatalyst, is proposed as an economical and eco-friendly method. Herein, amino-functionalized superparamagnetic Fe3O4@SiO2–NH2 nanoparticles with core-shell structure were constructed as a promising carrier for immobilization of laccase from Trametes versicolor. Compared with free laccase, Fe3O4@SiO2–NH2-Laccase displayed remarkable outcomes in all major areas such as temperature and storage stabilities, and tolerance to organic solvents and metal ions. The biocatalytic performance and reusability of Fe3O4@SiO2–NH2-Laccase were evaluated for the degradation of 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) in repeated cycles. Even after 10 successive reuses, the degradation rate of 2,4-DCP and 2,4,6-TCP were found to be 54.9% and 68.7%, respectively. The influences of solution pH, initial chlorophenol concentration, and temperature on the degradation rate of these two chlorophenols were evaluated. The degradation intermediate products including dimers, trimers, and tetramers of 2,4-DCP and 2,4,6-TCP were identified. Release of chloride ions was observed during the enzymatic degradation of these two chlorophenols. Based on the determination of intermediate products and released chloride ions, the degradation pathway that was involved in dehydrogenation, reactive radical intermediates formation, dechlorination, self-coupling and oligomers/polymers formation was proposed. The toxicity of these two chlorophenols and their intermediates was substantially reduced during the enzymatic degradation. The results of this study might present an alternative clean biotechnology for the remediation of 2,4-DCP and 2,4,6-TCP contaminated water matrices.

Efficient Fenton-like treatment of high-concentration chlorophenol wastewater catalysed by Cu-Doped SBA-15 mesoporous silica

Effective treatment for industrial wastewater that contains high concentration of chlorophenols is urgent and indispensable for environmental governance and human health due to their nonbiodegradable, carcinogenic and cytotoxic properties. Four kinds of Cu-containing mesoporous silica materials were utilized to catalyse Fenton-like treatment of high-concentration chlorophenols wastewater (1.0 g L−1). All of chlorophenols in various water matrices could be oxidatively decomposed in 35 min with the catalysis of Cu-doped SBA-15. Cu-doped SBA-15 with a Cu/Si molar ratio of 0.133 had the best catalytic activity in the oxidative degradation of 4-chlorophenol with an apparent reaction rate constant of 0.170 min−1 which was 1.3–3.6 times higher than those with other Cu-containing catalysts. After 300 min reaction, total organic carbon content of 4-chlorophenol solution declined continuously to 23.8% with an advisable utilization efficiency of H2O2 of 26.5%–68.4%. Electron spin resonance tests and quenching experiments demonstrated that Cu-doped SBA-15 had a selective catalytic activity in the decomposition of H2O2 into hydroxyl radicals which dominated the degradation of chlorophenols in wastewater. The redox of Cu(II)/Cu(I) in Cu-doped SBA-15 occurred efficiently, which could be attributed to chemical adsorption and electron transformation of organic molecular fragments onto Lewis acidic sites formed by the incorporation of Cu2+ ions in SBA-15. The biological toxicity of the treated 4-CP wastewater declined significantly in comparison with that of the original wastewater. Our work provided an effective way of the heterogeneous treatment of high-concentration chlorophenol wastewater.

Exposure to 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol and risk of thyroid cancer: a case-control study in China.

Thyroid cancer (TC) has inflicted huge threats to the health of mankind. Chlorophenols (CPs) were persistent organic pollutant and can lead to adverse effects in human health, especially in thyroid. However, epidemiological studies have revealed a rare and inconsistent relationship between internal exposure to CPs and TC risk. The purpose of this study was to investigate the correlation between urinary CPs and TC risk in Chinese population. From June 2017 to September 2019, a total of 297 histologically confirmed TC cases were recruited. Age- and gender-matched controls were enrolled at the same time. Gas chromatography-mass spectrometry (GC-MS) was used to determine the levels of three CPs in urine. Conditional logistic regression models were adopted to assess the potential association. Restricted cubic spline function was used to explore the non-liner association. After adjusting for confounding factors, multivariate analysis showed that, compared with the first quartile, the fourth quartile concentrations of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) were associated with TC risk (odds ratio (OR)2,4-DCP =2.28, 95% confidence interval (CI): 1.24-4.18; OR2,4,6-TCP =3.09, 95% CI: 1.66-5.77; ORPCP =3.30, 95% CI: 1.71-6.36, respectively), when CPs were included in the multivariate model and restricted cubic spline function as continuous variables, presenting significant dose-response relationships. Meanwhile, whether in the TC group with tumor diameter > 1 cm or metastatic TC, the changes of 2,4,6 TCP and PCP concentrations were positively correlated with the risk of TC. Our study suggests that higher concentrations of urinary CPs are associated with increased TC risks. Moreover, 2,4,6-TCP and PCP have certain effects on the invasiveness of thyroid cancer. Targeted public health policies should be formulated to reduce the CP pollution. These findings need further in-depth studies to confirm and relevant mechanism also needed to be clarified.

Enhanced reactivity of zero-valent aluminum/O2 by using Fe-bearing clays in 4-chlorophenol oxidation

Zero-valent aluminum (ZVAl) is a promising reductant because of its relatively low redox potential, which can efficiently activate molecular oxygen to generate reactive oxygen species. However, its long-term performance is limited by the intrinsic dense oxide layer and the passivation effect of the accumulative Al-(hydr)oxide on its surface during the reaction. In this study, four clay minerals with different compositions were mixed with ZVAl by ball milling to obtain four composites of ZVAl and clay (ZVAl-Clay), which were used to degrade a high concentration of 4-chlorophenol (4-CP) under ambient conditions. The oxidation efficiencies of different ZVAl-Clays were strongly relevant to Fe contained in the clay minerals. The Fe-free ZVAl-Clay presented poor oxidation performance, whereas the reaction efficiencies of those ZVAl composites with Fe-bearing clays exhibited varying degrees of improvement. In comparison with the original ZVAl, the highest oxidation rate increased by 23 times, the maximum increased OH production was approximately 8 times, and the corresponding mineralization efficiency improved by 38.7%. However, the levels of improved oxidation performance of various ZVAl-Clays were not positively correlated with their actual total Fe contents, and their degradation efficiencies might also be affected by other physical and/or chemical properties of different clays. The synergistic mechanism revealed by various characterizations was that electron transfer might occur from ZVAl to the structural Fe(III) of the clay through the basal plane or edge of clays triggered by ball milling. Thus, the partially produced Fe(II) on the clay surface promoted the Fenton-like reaction to decompose H2O2 into OH for efficient oxidation of 4-CP. In short, the ZVAl composites with Fe-bearing clays deserved further exploration as potential materials for efficient degradation of organic matters in wastewater samples.

Characterization of a Novel Laccase LAC-Yang1 from White-Rot Fungus Pleurotus ostreatus Strain Yang1 with a Strong Ability to Degrade and Detoxify Chlorophenols.

In this study, a laccase LAC-Yang1 was successfully purified from a white-rot fungus strain Pleurotus ostreatus strain yang1 with high laccase activity. The enzymatic properties of LAC-Yang1 and its ability to degrade and detoxify chlorophenols such as 2,6-dichlorophenol and 2,3,6-trichlorophenol were systematically studied. LAC-Yang1 showed a strong tolerance to extremely acidic conditions and strong stability under strong alkaline conditions (pH 9–12). LAC-Yang1 also exhibited a strong tolerance to different inhibitors (EDTA, SDS), metal ions (Mn2+, Cu2+, Mg2+, Na+, K+, Zn2+, Al3+, Co2+, and metal ion mixtures), and organic solvents (glycerol, propylene glycol). LAC-Yang1 showed good stability in the presence of Mg2+, Mn2+, glycerol, and ethylene glycol. Our results reveal the strong degradation ability of this laccase for high concentrations of chlorophenols (especially 2,6-dichlorophenol) and chlorophenol mixtures (2,6-dichlorophenol + 2,3,6-trichlorophenol). LAC-Yang1 displayed a strong tolerance toward a variety of metal ions (Na2+, Zn2+, Mn2+, Mg2+, K+ and metal ion mixtures) and organic solvents (glycerol, ethylene glycol) in its degradation of 2,6-dichlorophenol and 2,3,6-trichlorophenol. The phytotoxicity of 2,6-dichlorophenol treated by LAC-Yang1 was significantly reduced or eliminated. LAC-Yang1 demonstrated a good detoxification effect on 2,6-dichlorophenol while degrading this compound. In conclusion, LAC-Yang1 purified from Pleurotus ostreatus has great application value and potential in environmental biotechnology, especially the efficient degradation and detoxification of chlorophenols.

Associations between bisphenols, benzophenones, and chlorophenols with fecundability modified by dietary phenols

Background/Aim: Antioxidant dietary phenols, which are abundant in vegetables, fruits, and herbs, may ameliorate adverse associations between environmental phenols (found in food packaging, UV filters, herbicides, and disinfectants) and reproductive outcomes as they exert protective effects. We therefore evaluated whether dietary phenols modified the relationship between environmental phenols and fecundability.Methods: In a prospective cohort study following 1,228 women for up to 6 menstrual cycles while trying to conceive (United States, 2007-2011), concentrations of dietary phenols, bisphenols, benzophenones, and chlorophenols were measured in urine at baseline. Pregnancy was assessed using urine hCG. We used discrete Cox regression to examine how low-to-moderate (<75th percentile) versus high (≥75th percentile) levels of dietary phenols modified associations between environmental phenols and fecundability, adjusting for potential confounders.Results: Bisphenol-S was associated with reduced fecundability (fecundability odds ratio [FOR] 0.95, 95% confidence interval [CI] 0.90, 1.00, per log-unit increase), independent of dietary phenols, though other phenols were not associated with fecundability. Selected environmental phenols were associated with reduced fecundability in women with low-to-moderate dietary phenols but not in women with higher dietary phenols. Specifically, bisphenol-A was associated with reduced fecundability in women with low-to-moderate gallic acid (FOR 0.90, 95% CI 0.81, 1.01). 4-hydroxybenzophenone was associated with reduced fecundability in women with low-to-moderate versus high 3,4-dihydroxyphenylacetic acid (FOR 0.90, 95% CI 0.83, 0.97 versus FOR 0.87, 95% CI 0.69, 1.11, respectively) and caffeic acid (FOR 0.88, 95% CI 0.82, 0.96 versus FOR 1.18, 95% CI 0.94, 1.48, respectively). For pentachlorophenol, reduced fecundability was observed in women with low-to-moderate 3-hydroxybenzoic acid (FOR 0.90, 95% CI 0.81, 1.00) and gallic acid (FOR 0.89, 95% CI 0.81, 0.99).Conclusions: Consumption of dietary phenols may help mitigate the adverse effect of selected environmental phenols on fecundability, highlighting the potential interplay between diet and environmental exposures among women attempting pregnancy.

Environmental chemical exposures in the urine of dogs and people sharing the same households.

Urothelial carcinoma (UCC) develops in both humans and dogs and tracks to regions of high industrial activity. We hypothesize that dogs with UCC may act as sentinels for human urothelial carcinogen exposures. The aim of this pilot study was to determine whether healthy people and dogs in the same households share urinary exposures to potentially mutagenic chemical carcinogens. We measured urinary concentrations of acrolein (as its metabolite 3-HPMA), arsenic species, 4-aminobiphenyl, and 4-chlorophenol (a metabolite of the phenoxyherbicide 2,4-D) in healthy dogs and their owners. We assessed possible chemical sources through questionnaires and screened for urothelial DNA damage using the micronucleus assay. Biomarkers of urinary exposure to acrolein, arsenic, and 4-chlorophenol were found in the urine of 42 pet dogs and 42 owners, with 4-aminobiphenyl detected sporadically. Creatinine-adjusted urinary chemical concentrations were significantly higher, by 2.8- to 6.2-fold, in dogs compared to humans. Correlations were found for 3-HPMA (r = 0.32, P = 0.04) and monomethylarsonic acid (r = 0.37, P = 0.02) between people and their dogs. Voided urothelial cell yields were inadequate to quantify DNA damage, and questionnaires did not reveal significant associations with urinary chemical concentrations. Healthy humans and pet dogs have shared urinary exposures to known mutagenic chemicals, with significantly higher levels in dogs. Higher urinary exposures to acrolein and arsenic in dogs correlate to higher exposures in their owners. Follow-up studies will assess the mutagenic potential of these levels in vitro and measure these biomarkers in owners of dogs with UCC.