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A commercial thin‐film membrane (unmodified) of polyamide improved by poly(vinyl alcohol) (PVA)‐coated membranes (modified) was investigated for separating phenol in sour water by reverse osmosis. Dependences of pressure and pore surface area on flux and phenol rejection were tested. A graphical correlation was found between the relative flux decline and phenol concentration decrease in the feed. The modified membrane provided rejection of 86 % at 2 bar with the highest permeate flux of 8.46 L m−2h−1. The average contact angle for the former membrane was 58.4°, while that for the modified membrane was 49.1°. The reduction in contact angle enhances the surface hydrophilicity of the membrane leading to the antifouling effect. The modified membrane provides 95.4 % flux recovery compared to the unmodified membrane that provides only 66.2 %. [ABSTRACT FROM AUTHOR]

Pea peels were used for the preparation of biochar at different temperatures (250 °C: PP250, 500 °C: PP500 and 750 °C: PP750) using slow pyrolysis for 1 h and used for the phenol removal from an aqueous medium. Biochar samples were characterized by SEM, XRD and FT‐IR. The phenol removal was examined as a function of pH, temperature, and NaCl and urea concentration. The optimum pH and temperature were found to be 6.0 and 25 °C respectively. Presence of NaCl and urea primarily affected the adsorption capacity of PP250 and slightly affected the adsorption potential of PP500 and PP750. The maximum biosorption capacity for the PP250, PP500 and PP750 were found to be 34.63, 46.70, and 60.10 mg/g respectively. The Langmuir isotherm and Pseudo‐second order kinetic model best explained the adsorption. Thermodynamic parameters corroborated the physical and exothermic nature of adsorption. PP750 can preferably be used for phenol removal than PP500 and PP250. [ABSTRACT FROM AUTHOR]

BACKGROUND Photocatalytic degradation is considered as an effective and eco‐friendly alternative for removal of persistent pollutants. The enhancement of the photocatalytic properties of conventional photocatalysts such as CeO2 can be realized by surface modification with metals or nonmetals, which allows a reduction in the recombination frequency of charge carriers. In this study, superficially phosphated CeO2 materials with various anion contents obtained using an impregnation method were evaluated in the photodegradation of phenol under UV irradiation. RESULTS: The addition of phosphate anions promoted an increase in the surface area and a slight decrease in the crystallite size. The anchorage of the phosphate anions was via bidentate mode. An enhancement in the degradation of the pollutant was evidenced using the phosphated materials with respect to the results observed using unmodified CeO2. Also, an effect of the content of anions was evidenced, the optimal amount being equal to 1.0 wt%. CONCLUSIONS: The surface modification of CeO2 with phosphate anions favors a control of the physical and chemical properties of the semiconductor and the effective separation of electron–hole pairs, which leads to an increase in the photocatalytic activity. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The discharge of raw industrial wastewaters, specifically coking wastewater, represents a severe environmental problem. In this work, a phenol‐degrading aerobic strain isolated from a hydrocarbon contaminated site, Achromobacter sp. C‐1, was tested for degrading raw coking wastewater to explore its potential for use in biological treatment. Initially, phenol degradation was reached after 24 h of inoculation in synthetic wastewater [600 mg/L of phenol]. The maximum specific degradation rate was 0.436 h–1 found in the concentration 300 mg/L. In a raw industrial wastewater containing a mixture of phenols as carbon source [phenol 370 mg/L, m‐cresol 100 mg/L and o‐cresol 60 mg/L], 90% biodegradation of a mixture of phenols was achieved after 80 h of inoculation. Following the biodegradation process to remove the colour from the wastewater, polishing was performed by activated carbon adsorption, resulting in a clear wastewater (without colour and contaminants) ready for industrial reuse purposes. These results provided useful information about use of the phenol‐degrading bacteria for bioaugmentation in industrial wastewater treatment improving the quality of final wastewater. The quality of the resulting wastewater was confirmed by mass spectrometry analysis. This work shows the biodegradation process could be a cost‐effective and promising solution for the treatment and reuse of phenolic wastewater. [ABSTRACT FROM AUTHOR]

BACKGROUND: Functionalized activated carbon (FAC) was prepared by immobilizing the activated carbon (AC) synthesized from Acacia fumosa seeds in cacium-alginate beads. Synthesized FAC has been blended with polyphenylsulfone (PPSU) in the composition of 0.25 to 1wt% with an increment of 0.25wt% to prepare composite membranes of PPSU/FAC by wet phase inversion method. The existence of FAC in PPSU was confirmed by Fourier transform infra-red spectroscopy (FTIR) studies by the presence of characteristic functional groups of FAC. The influence of FAC on adsorption enhanced rejection of phenol during membrane filtration has been investigated. RESULTS: The hydrophilicity of PPSU/FAC composite membranes has been improved by FAC as there was a profound reduction in contact angle from71.8° to 43.8°.With the minimum loading of 0.25wt% of FAC in PPSU, themaximum adsorption of phenol has taken place suggesting that the better dispersion of minimal loading will offer higher accessibility to adsorptive sites. CONCLUSIONS: The adsorption of phenol on FACwas observed to be higher in PPSU/FAC compositemembranes when compared with FAC being used solely as an adsorbent. [ABSTRACT FROM AUTHOR]

Phenols are considered as organic pollutants that are discharged into the environment causing contamination of drinking water, aquatic life, and plants, and therefore, affecting human. Various treatment technologies for removal of the pollutants from water have been used such as, liquid-liquid extraction, ionic exchange with resins, and membrane processes. In this study, removal and adsorption of phenol from aqueous solutions were studied using a polyamide thin film composite reverse osmosis membrane denoted as AG 2514 TF from Osmonics company. The influence of different parameters, such as, feed concentration, ionic strength, transmembrane pressure, and recovery on the elimination of phenol was also studied. In addition, the effect of transmembrane pressure, feed concentration, and ionic strength on the adsorption of phenol was investigated. For a better understanding of the behavior of the membrane and to get more insights into the retention of phenol, the membrane was characterized with the determination of its surface charge and also by the mechanism of transport through this membrane. The results show that the retention of phenol by AG membrane exceeds 40% and may reach 80%. This was found to depend on feed concentration, ionic strength, transmembrane pressure, and recovery. The adsorption amounts were too low and did not exceed 23%. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 982-989, 2015 [ABSTRACT FROM AUTHOR]

Crosslinked copolymer beads were prepared by suspension polymerization of 4-vinylbenzyl chloride (VBC) and ethyleneglycole dimethacrylate (EGDMA) mixtures. The resulting copolymer beads with quaternary amide functions were prepared in two steps: (1) modification of imidazole with PVBC and (2) quaternization of imidazole modified beads with chloroacetamide. The resulting polymer resin, which had a chloroacetamide content of 4.50 mmol/g, was effective in extracting phenol from aqueous solutions. The phenol sorption capacity was around 0.208 g phenol/g resin in non-buffered conditions. The adsorption conditions (initial phenol concentration and pH) were varied to evaluate the mechanism of adsorption of phenol on the prepared resin. This resin is also able to remove phenol completely even from highly diluted aqueous phenol solutions. [ABSTRACT FROM AUTHOR]

BACKGROUND Improved Fe2O3/Al2O3 catalysts were studied for the catalytic oxidation of concentrated phenol solutions (5 g L−1) with H2O2. To enhance catalyst stability, two strategies were investigated: the use of a high calcination temperature and a step of immersion into an organic acid solution. The reaction runs were performed in a continuous reactor at 70°C and atmospheric pressure. RESULTS For all the catalysts, almost complete phenol degradation was achieved. The mineralization levels were incomplete, reaching 60 and 50% for the catalysts treated with acetic and oxalic acid, respectively. The leaching levels were reduced from 25% (for the untreated catalyst) to 11% after the immersion in oxalic acid. In all cases, the formation of reversible carbonaceous deposits was observed during reaction and a progressive decay in phenol, TOC and H2O2 conversions was registered. CONCLUSION Catalyst resistance to leaching was significantly enhanced by combining both thermal and acidic treatments. These procedures did not affect the catalytic wet hydrogen peroxide oxidation ( CWHPO) performance in terms of mineralization levels. The lixiviation levels were acceptable, taking into account the strong acidic reaction medium. Deactivation processes might be primarily associated with the formation of reversible carbonaceous deposits due to intermediates accumulation onto the catalyst surface. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Application of mutated recombinant horseradish peroxidase ( HRP) for phenol removal from refinery effluents is reported. Recombinant HRP produced in Escherichia coli suffers from the disadvantage of lacking glycosylation, which affects its catalytic efficiency and stability toward inactivating parameters such as increased temperature and enhanced amounts of hydrogen peroxide. In the present study, the previously reported variant (in which Asn268 was substituted with Asp, N268 D) with improved stability characteristics and catalytic efficiency was used to remove phenol from a petroleum refinery effluent. The presence and removal of phenol was studied by high-performance liquid chromatography; the precipitated oxidized phenol was also observed and removed from the sample by centrifugation. Results showed that the N268 D variant can remove 61%, 67%, and 81% of phenol from effluent in 1, 2, and 16 H, respectively. By exploiting the N268 D mutant, removal of 50% phenol could be achieved in 42 Min, which was more than 22 times less than the treatment time required by native recombinant enzyme. [ABSTRACT FROM AUTHOR]

BACKGROUND Studies with peroxidase (EC 1.11.1.7) have demonstrated that phenolic precipitate adsorbs free enzyme, inactivating it. The end-product inactivation model has been proposed to explain the effect. Additives, such as polyethylene glycol and Triton X-100, were reported to effectively extend enzyme lifetime by preventing the adsorption. RESULTS It was found that soybean peroxidase ( SBP, EC 1.11.1.7) trapped in precipitate during phenol polymerization retains activity. Contrary to the end-product inactivation model, recycling precipitate effectively utilized the active SBP. The minimum SBP concentration required for the subsequent batch reaction removal of 1 mmol L-1 phenol from aqueous solution was reduced from 1.2 to 0.5 U mL-1. SBP adsorption on the precipitate was proven to be reversible by the addition of Triton X-100. Thus, a new explanation of SBP fate during the reaction is suggested: SBP is immobilized in situ in an active form with reduction of specific activity rather than inactivation. The adsorption is characterized by a Langmuir isotherm. CONCLUSIONS The phenolic precipitate immobilizes SBP in an active form, consistent with the Langmuir isotherm model. Recycling the precipitate improves the enzyme economy in phenol removal. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Advance oxidation process was employed as a pretreatment of industrial wastewater. For this purpose, the use of heavy metals as a catalyst is necessary but also complicated because homogeneous catalysts are difficult to recover after reaction process. The heterogenization of Cu(II) ions was proposed by taking advantage of the adsorptive characteristics of polymeric matrices. Crosslinked poly(4-vinylpyridine) of 2 and 25% and poly( D-glucosamine) were tested as supports of copper. Adsorption was employed to heterogenize Cu(II) by considering the influences of pH and temperature on the process. The catalysts were evaluated by their metal content, catalytic behavior for the oxidation of phenol and leaching degree after reaction. Poly(4-vinylpyridine) 2% was the best material for Cu(II) immobilization with an adsorption capacity of 90 mg g−1. Afterward, poly(4-vinylpyridine) 2%, Cu(II) achieved 64% of phenol conversion, which represents a favorable result for the oxidation of phenol as the model of industrial wastewater pretreatments. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 269-278, 2013 [ABSTRACT FROM AUTHOR]

This study investigated the phenol rejection character-istics of some nanofiltration membranes during treatment of coke wastewater. Four different types of composite polyamide commercial nanofiltration membranes (Sepro, USA) were tested under different operating conditions including transmembrane pressure, pH and recovery rate. When pressure was increased from 4 to 16 bars, the percentage of rejection of phenol in the permeate increased from 72.5% to 97.7% while yielding a high flux of 118 litres per square meter per hour(LMH) at a volumetric cross flow rate of 800 litres per hour at pH 10 (in recirculation mode) in case of NF1 membrane. The effect of recovery rate on the rejection coefficient of phenol and flux was also studied in concentrated mode and found that a recovery rate of up 55% nanofiltration was successfully operated without much decline of flux and rejection coefficient. Finally, nanofiltration had great efficiency in phenol removal from industrial wastewater and was considered suitable regarding its operation. [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the impact of pH, sedimentation time and concentration of polystyrene sulfate (PSS) on the treatment of phenol effluent from coking plant. Ammonia, cyanide and thiocyanite are some of the components of the coke-plant wastewater. Polystyrene foam was crushed to pieces and the crushed waste was dissolved in chloroform and stirred. One type of organic wastewater was used to assess the flocculating effectiveness of PSS. Results revealed that the optimum conditions were ascertained for the removal of phenol. As the sedimentation time increases, the removal capacity of phenols increased.