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In this study, the treatability of olive mill wastewater by iron-activated persulphate (PS) oxidation was investigated. Central Composite Design (CCD) was applied to optimise the process parameters and establish a mathematical model for total phenol, chemical oxygen demand (COD), and colour removal from olive mill wastewater. The effect of process variables (PS dose, Fe2+ dose, initial pH, and reaction time) on pollutant removal efficiency was evaluated. The correlation coefficients of the quadratic polynomial equations were high for COD, total phenol, and colour removal by PS oxidation, and the model was found to be applicable. Optimum conditions determined by the developed model for maximum COD removal were pH 5, PS dose 206.7 mM, Fe2+ dose 70 mM, and reaction time 95 min. The COD, total phenol, and colour removal efficiencies estimated by the applied model were 46.74%, 94.62%, and 96.04%, respectively. The removal efficiencies obtained under optimum conditions as a result of the validation experiments were 45.5%, 93.8%, and 95.5% for COD, total phenol, and colour removal, respectively. The results of the study showed that PS oxidation in which Fe2+ is used as an activator is a suitable alternative for olive mill wastewater treatment. [ABSTRACT FROM AUTHOR]

Biochar is an inexpensive alternative to activated carbon for adsorption of phenolic pollutants. Dissolved solids released from biochar, including organic and inorganic compounds, may affect the stable adsorption efficiency of biochar as an adsorbent. Using saccharification residue of rice straw to prepare biochar (biochar-SR) can improve the stability of biochar and reduce its cost. Biochar-SR and biochar prepared directly from rice straw (biochar-O) contained basically the same types of surface functional groups but the numbers of lactone, phenolic, and carbonyl groups in biochar-SR were 55.56%, 50.57%, and 311.56% higher than those in biochar-O, respectively. The total volume and diameter of pores and specific surface area of biochar-SR were 38%, 51%, and 167% higher than those of biochar-O, respectively. The adsorption data of biochar-SR fit better to a Freundlich model, indicating non-uniform multilayer adsorption. Compared with biochar-O, the equilibrium adsorption capacity of biochar-SR was 41.63% higher, and it had significantly better stability and reusability. These results demonstrated that the preparation method of biochar-SR could significantly improve the adsorption capacity, stability, and environmental and economic benefits of biochar as an adsorbent. [ABSTRACT FROM AUTHOR]

The electro-Fenton oxidation process was used to treat organic pollutants in industrial wastewater as it is one of the most efficient advanced oxidation processes. The novel cell in this process consists of a prepared PbO2 electrode by electrodeposition on graphite substrate and carbon fiber modified with graphene as a cathode. X-ray diffraction, fluorescence, analysis system, atomic force microscopy, and scan electron microscopy were used to characterize the prepared anode and cathode. XRD patterns clearly show the characteristic reflection of the mixture of α - and β phases of PbO2 on graphite and carbon fiber, and AFM results for cathode and anode present that PbO2 on graphite substrate and graphene on carbon fiber surface are on a nanoscale. Contact angle measurement was determined for the carbon fiber cathode before and after modification. The anodic polarization curve showed a higher anodic current when utilizing the PbO2 anode than the graphite anode. Phenol in simulated wastewater was removed by electro-Fenton oxidation at 8 mA/cm² current density, 0.4 mM of ferrous ion concentration at 35 °C up to 6 h of electrolysis. Chemical oxygen demand for the treated solution was removed by 94.02% using the cell consisting of modified anode and cathode compared with 81.23% using modified anode and unmodified cathode and 79.87% when using unmodified anode and modified cathode. [ABSTRACT FROM AUTHOR]

There is a growing interest in the development of effective strategies for the removal of phenolic compounds from wastewater, which pose a threat to the environment and human health. It is known that the enzyme peroxidase is effective in removing phenolic compounds from wastewater. In various studies, it has been reported that boron nitride-based materials remove organic and inorganic pollutants from the environment through surface complexation, π-π stacking, and electrostatic interactions. In this study, a magnetically oriented peroxidase-conjugated BN/Ni/Au nanowire system was designed for the removal of model phenolics. It is aimed to remove phenolic compounds effectively and with high efficiency thanks to peroxidase conjugated with surface modification of the Au segment and BN segment in the nanowire structure. In addition, thanks to the magnetic property of the Ni segment, the designed nanowire can be easily removed from the environment after use. The amount of conjugated peroxidase was calculated as 188.6 mg of enzyme per gram of nanowire. Stability experiments were also carried out and the optimum pH's of the free and conjugated enzymes were found to be 8.0 and the optimum temperatures were found to be 60 °C. The kinetic parameters showed that the conjugated enzyme had an increased interest in its substrate relative to the free enzyme. As a result of thermal stability, storage life, and operational stability experiments, it was found that the conjugated enzyme retains its initial activity at a high rate. Finally, phenolic compound removal of peroxidase-conjugated magnetic nanowires was investigated with model compounds and removal efficiency of up to 89% for phenolic compounds was recorded. [ABSTRACT FROM AUTHOR]

Abstract Phenolic compound even at low concentrations, are considered to be priority pollutants due to their significant toxicity. Electrospinning was used to create a polyacrylonitril (PAN) nanofiber, which was then impregnated with graphene oxide (GO). After a preliminary investigation into the electrospinning parameters (e.g., using various voltages and polymer concentrations), the electrospun nanofibres were tuned, this study evaluated the effectiveness of these materials in removing phenolic compounds from wastewater through adsorption. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the synthesized nanofiber mats. The scanning electron microscopy (SEM) analysis revealed that the structure of nanofiber mats was altered by the addition of graphene oxide (GO) in different ratios. Specifically, the surface of the fibres exhibited increased roughness, and the diameter of the fibres also experienced an increase. The average diameter of the fibres was measured to be (134.9 ± 21.43 nm) for the PAN/2.5% GO composite and (198 ± 33.94 nm) for the PAN/5% GO composite. FTIR spectra of the PAN/GO nanocomposites nanofiber displayed distinct peaks associated with graphene oxide (GO). These included a wide peak at 3400 cm−1, related to the presence of hydroxyl (O–H) groups, as well as peaks on 1600 as well as 1000 cm−1, which indicated the existence of epoxy groups. In this study response surface methodology (RSM) was implemented. To enhance the efficiency of removing substances, it is necessary to optimise parameters such as pH, contact time, and dosage of the adsorbent. The optimum pH for removing phenol via all nanofiber mats was determined to be 7, while at a dose of 2 mg dose adsorbents maximum removals for pure PAN, PAN/2.5 GO, and PAN/5 GO were 61.3941, 77.2118, and 92.76139%, respectively. All the adsorbents obey Langmuir isotherm model, and the empirical adsorption findings were fitted with the second-order model kinetically, also non-linear Elovich model. The maximal monolayer adsorption capacities for PAN, PAN/2.5 GO, and PAN/5 GO were found to be 57.4, 66.18, and 69.7 mg/g, respectively. Thermodynamic studies discovered that the adsorption of phenol on all adsorbents nanofiber mats was exothermic, the adsorption of phenol on nanofiber mats decreases as the temperature increases. All the adsorbents exhibit negative enthalpy and entropy. The PAN/GO composite's superior phenol removal suggested that it could be used as a latent adsorbent for efficient phenol removal from water and wastewater streams.

Biochar derived from kenaf, a fast-growing plant, was used as a adsorbent in this study to remove phenol from aqueous solutions. Kenaf-derived biochar (KDB) was prepared at various temperatures (300–750 °C) and the relationship between the phenol adsorption mechanism and physicochemical properties was investigated. The highest phenol adsorption by KDB was achieved at 750 °C, and KDB pyrolyzed at 750 °C (KDB-750) had the lowest O/C (0.11) and H/C (0.01) values as well as the highest specific surface area (116.74 m2/g). Phenol molecules could be adsorbed on the surface of KDB via hydrophobic attraction and π–π interaction. Kinetic studies revealed that the adsorption reached equilibrium at 48 h, and the adsorption process was well explained by the pseudo-second-order model. The maximum phenol adsorbed obtained from equilibrium adsorption experiments was 41.1 mg/g, which is comparable to that reported in the literature. The enthalpy and entropy changes during phenol adsorption by KDB-750 were 22.3 kJ/mol and 64.2 J/K‧mol, respectively. The amount of phenol adsorbed decreased gradually from 38.5 to 32.4 mg/g as the pH of the solution increased from 3 to 9, and it decreased sharply from 32.4 to 28.9 mg/g as the pH increased from 9 to 11. When 0 to 200 mM NaCl was added to the phenol solution, the adsorbed amount decreased from 38.1 to 29.5 mg/g. Moreover, for a KDB-750 dosage of 10 g/L, > 90% of the phenol was removed. Thus, KDB-750, which is a low-cost and abundant adsorbent, could potentially be used as an adsorbent to remove phenol effectively. [ABSTRACT FROM AUTHOR]

Horseradish peroxidase is an enzyme commonly used in wastewater treatment due to its ability to oxidize a wide range of organic compounds, including phenols. The use of peroxidases immobilized onto magnetite nanoparticles improves the enzyme's stability and catalytic activity, but also facilitates their simply separation and reuse. In the present study, a covalent immobilization of horseradish peroxidase onto polyethylene glycol-modified magnetite nanoparticles via glutaraldehyde was performed in order to prepare a promising bio-catalyst for phenol removal from wastewater. The efficiency of the immobilized enzyme in phenol removal in the presence of hydrogen peroxide and polyethylene glycol as stabilizer was measured. The general toxicity of bio-treated water (Allium cepa test) was also investigated. All analyses were performed in parallel for the free enzyme. The immobilized enzyme showed the highest activity at a temperature of 50 °C and pH 7.0 and retained 50% of its activity after four washing cycles. Additionally, its storage stability was higher compared to the free form, as well as its tolerance against inactivation to heavy metals and organics-induced inhibition. Since the tested enzymatic system was very efficient in phenol removal from water (75% for 2 h), along with the substantial reduction of the toxicity of the tested water (48%), it can be considered as an environmentally acceptable bio-catalyst for phenol-containing wastewater treatment. [ABSTRACT FROM AUTHOR]

In recent years, the increasing prevalence of phenolic pollutants emitted into the environment has posed severe hazards to ecosystems and living organisms. Consequently, there is an urgent need for a green and efficient method to address environmental pollution. This study utilized waste sludge as a precursor and employed a hydrothermal-calcination co-pyrolysis method to prepare manganese (Mn)-doped biochar composite material (Mn@SBC-HP). The material was used to activate peroxydisulfate (PDS) for the removal of phenol. The study investigated various factors (such as the type and amount of doping metal, pyrolysis temperature, catalyst dosage, PDS dosage, pH value, initial phenol concentration, inorganic anions, and salinity) affecting phenol removal and the mechanisms within the Mn@SBC-HP/PDS system. Results indicated that under optimal conditions, the Mn@SBC-HP/PDS system achieved 100% removal of 100 mg/L phenol within 180 min, with a TOC removal efficiency of 82.7%. Additionally, the phenol removal efficiency of the Mn@SBC-HP/PDS system remained above 90% over a wide pH range (3–9). Free radical quenching experiments and electron spin resonance (ESR) results suggested that hydroxyl radicals (·OH) and sulfate radicals (SO4-) yed a role in the removal of phenol through radical pathways, with singlet oxygen (1O2) being the dominant non-radical pathway. The phenol removal efficiency remained above 90%, demonstrating the excellent adaptability of the Mn@SBC-HP/PDS system under the interference of coexisting inorganic anions or increased salinity. This study proposes an innovative method for the resource utilization of waste, creating metal-biochar composite catalysts for the remediation of water environments. It provides a new approach for the efficiency of organic pollutants in water environments. [ABSTRACT FROM AUTHOR]

Phenolic compound even at low concentrations, are considered to be priority pollutants due to their significant toxicity. Electrospinning was used to create a polyacrylonitril (PAN) nanofiber, which was then impregnated with graphene oxide (GO). After a preliminary investigation into the electrospinning parameters (e.g., using various voltages and polymer concentrations), the electrospun nanofibres were tuned, this study evaluated the effectiveness of these materials in removing phenolic compounds from wastewater through adsorption. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the synthesized nanofiber mats. The scanning electron microscopy (SEM) analysis revealed that the structure of nanofiber mats was altered by the addition of graphene oxide (GO) in different ratios. Specifically, the surface of the fibres exhibited increased roughness, and the diameter of the fibres also experienced an increase. The average diameter of the fibres was measured to be (134.9 ± 21.43 nm) for the PAN/2.5% GO composite and (198 ± 33.94 nm) for the PAN/5% GO composite. FTIR spectra of the PAN/GO nanocomposites nanofiber displayed distinct peaks associated with graphene oxide (GO). These included a wide peak at 3400 cm−1, related to the presence of hydroxyl (O–H) groups, as well as peaks on 1600 as well as 1000 cm−1, which indicated the existence of epoxy groups. In this study response surface methodology (RSM) was implemented. To enhance the efficiency of removing substances, it is necessary to optimise parameters such as pH, contact time, and dosage of the adsorbent. The optimum pH for removing phenol via all nanofiber mats was determined to be 7, while at a dose of 2 mg dose adsorbents maximum removals for pure PAN, PAN/2.5 GO, and PAN/5 GO were 61.3941, 77.2118, and 92.76139%, respectively. All the adsorbents obey Langmuir isotherm model, and the empirical adsorption findings were fitted with the second-order model kinetically, also non-linear Elovich model. The maximal monolayer adsorption capacities for PAN, PAN/2.5 GO, and PAN/5 GO were found to be 57.4, 66.18, and 69.7 mg/g, respectively. Thermodynamic studies discovered that the adsorption of phenol on all adsorbents nanofiber mats was exothermic, the adsorption of phenol on nanofiber mats decreases as the temperature increases. All the adsorbents exhibit negative enthalpy and entropy. The PAN/GO composite's superior phenol removal suggested that it could be used as a latent adsorbent for efficient phenol removal from water and wastewater streams. [ABSTRACT FROM AUTHOR]

The study focuses on micellar-enhanced pressure-driven membrane separation (RO, NF, UF), for phenol removal. The rationale was to develop, a simple and efficient technique for complete remediation of phenol. For this, experiments toward integration of the pressure-driven membrane processes and comparative performance analysis were undertaken. Effect of micellar aggregation, nature of surfactant, phenol loading, and process parameters on processes like nanofiltration and reverse osmosis were studied. Cost–benefit analysis was also carried out to assess the techno-commercial viability of the process. Comparative phenol removal efficiency obtained follows the order MENF > MEUF > MERO. Combined MEUF and MENF demonstrated sustained high removal efficiencies of up to 95% and above. Subsequently surfactant regeneration and its reuse were investigated. Competitive phenol removal efficiencies in the range of 80–87% were attained using regenerated surfactant when tested up to 4 operational cycles. Several useful insights about surfactant-mediated pressure-driven transport and techno-economic analysis were gained through this study. [ABSTRACT FROM AUTHOR]

The aim of the study was to use regenerated activated carbon to adsorb phenol from a river. Coconut shell activated carbon was derived from used tap water filter cartridges. The activated carbon was carbonised and then activated with KOH at 200°C, under a nitrogen atmosphere. The resulting adsorbent was characterised on the basis of nitrogen adsorption by Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) analysis and point of zero charge (pH PZC). The study of periodic adsorption included kinetic and equilibrium modelling, determined the effect of solution pH on efficiency and the possibility of regeneration and reuse of the adsorbent. The efficiency of phenol removal from model water was evaluated, followed by the possibility of their adsorption from a polluted river in Silesia Province. Phenol adsorption followed pseudo-second-order kinetics. The adsorbents showed high adsorption abilities, as determined by the Langmuir isotherm model. The model fits the experimental data well. The concentration of phenol in the river was in the range of 0.45–0.77 mg∙dm– 3, which means that its value was at least five times higher than the standard values. The use of regenerated activated carbon from waste filter cartridges removed phenol from the river by 78% using optimal test parameters.

Most of the researches on tin oxide coatings as electrode materials were done on titanium, in this ‎study, the aim was to create pure SnO2 films on graphite substrate, which is more prevalent than ‎titanium. There is a lack in investigation the effect of SnCl2 and HNO3 concentrations on the prepared ‎SnO2 electrode; therefore, the aim of this work is to study these effects precisely. Also, no previous ‎study investigated the removal of phenol sonoelectrochemically by SnO2 electrode, which would be ‎accomplished in the present work. The tin dioxide electrode was produced by cathodic electrodeposition ‎using an SnCl2.2H2O solution in the presence of HNO3 and NaNO3 on a graphite plate substrate. The ‎impact of various operating parameters (current density (CD), HNO3 concentration, and SnCl2.2H2O ‎concentration) on the morphology and structure of the SnO2 deposit layer was thoroughly investigated. ‎The physical structures of the SnO2 film were determined by X ray diffraction (XRD), surface ‎morphology was characterized using field-emission scanning electron microscopy (SEM), and chemical ‎composition was analyzed using energy-dispersive X-ray spectroscopy (EDX). In a batch reactor, the ‎sonoelectrochemical oxidation of phenol was tested to determine the performance of the best SnO2 ‎electrodes for phenol degradation and any organic byproducts. It was discovered that 10 mA/cm2, 50 ‎mM of SnCL2.2H2O, and 250 mM of HNO3 were the optimum conditions to prepare SnO2 electrodes, ‎which produced the smallest crystal size, with no appeared cracks, and gave the best phenol removal. ‎The best prepared electrode was tested in the sonoelectrochemical oxidation of phenol with two ‎different electrolytes and different CD, and the results showed that the phenol removal was 76.87% and ‎‎64.68% when using NaCl and Na2SO4, respectively, and was 63.39, 76.87, and 100% for CD at 10, 25, ‎and 40 mA/cm2, respectively.‎

In the present work, Response Surface Methodology (RSM) was utilized to optimize process variables and find the best circumstances for indirect electrochemical oxidation of mimicked wastewater to remove phenol contaminants using prepared ternary composite electrode. The electrodeposition process is used for the synthesis of a ternary composite electrode of Mn, Co, and Ni oxides. The selected concentrations of metal salts of these elements were 0.05, 0.1, and 1.5 M, with constant molar ratio, current density, and electrolysis time of 1:1:1, 25 mA/cm2, and 2 h. Interestedly, the gathered Mn-Co-Ni oxides were deposited at both the anode and cathode. X-ray diffraction (XRD) and scanning electron microscopy (SEM) facilitated the qualitative characterization of surface structure and morphology of the accumulated oxides. The energy dispersive X-ray (EDX) provided a semi-quantitative analysis of deposit composition. The atomic force microscopy (AFM) apparatus quantified the roughness. We examined the efficiency of composite electrodes in coinciding with the removal of Chemical Oxygen Demand (COD) under current densities of 40, 60, and 80 mA/cm2, pH values of 3, 4, and 5, and NaCl concentrations of 1, 1.5, 2 g/l. RSM covered the optimization of process parameters in conjunction with Central Composite Design (CCD). The COD represented the response function in the optimization procedure. The optimal current density, NaCl concentration, and pH magnitude were 80 mA/cm2, 1.717 g/l, and 3, respectively. The efficiency of COD elimination of 99.925% attained after 1 hour of indirect electrochemical oxidation with an energy consumption of 152.380 kWh per kilogram of COD. The COD elimination model is significant based on the correlation coefficient (R2) and F-values, and the experimental data fitted well to a second-order polynomial model with R2 of 98.93%.

Phenols in industrial wastewater are a great threat to human and aquatie life. For removing sueh a hazardous pollutant, adsorption is one of the effieient teehniques. The eurrent study highlights the preparation of Dracaena sanderiana based aetivated earbon and its eharaeterization, physieal and ehemieal aetivation and applieation. At the lab seale variable doses of aetivated earbon (AC) and its modified forms sueh as aeid treated and furnace treated were applied for the removal of phenol from synthetie solution. The highest removal effieieney was observed at a dose of 0.2 g, 120 rpm and neutral pH (7) with a eontaet time of 1 h for aeid treated AC. For optimization of this proeess, the addition of anthraeite eoal to aeid treated AC resulted in the enhaneement of its adsorbability. The FT-IR speetrum has provided ample information regarding funetional groups responsible for the adsorbent after treatment. This study eoneludes that the adsorption of phenol through AC in eombination with anthraeite eoal is an effeetive treatment option. [ABSTRACT FROM AUTHOR]

The feasibility of using modified aetivated earbon (AC) obtained from disearded agrieultural waste, ineluding earrot residues, sawdust and orange pulp for phenol removal from aqueous solution was studied. The results showed maximum removal was found in sawdust AC eompared to orange pulp AC and earrot waste AC, 76%, 73% and 72% respeetively. The maximum result of sawdust AC was aehieved at eoneentration of 10 mg/L, pH 4.5, 1.5 h and 2 g dose whereas for orange pulp AC and eoneentration of 10 mg/L, pH 7.5, 2 h and 2 g dose of orange pulp AC. The ANOVA analysis was performed to eheek the suitability of eentral eomposite design and the quadratie model was found to be appropriate. This study eoneluded that natural, low-eost bio-sorbent derived from sawdust, orange pulp and earrot residues may be useful for phenol removal. [ABSTRACT FROM AUTHOR]

Most of the studies on tin oxide coatings as electrode materials were conducted on titanium; in this study, the aim was to create pure tin oxide (SnO2) films on graphite substrate, which is more prevalent than titanium. There is a lack in investigation the effect of SnCl2 and HNO3 concentrations on the prepared SnO2 electrode; therefore, the aim of this work was to study these effects precisely. Also, no previous study investigated the removal of phenol sonoelectrochemically by a SnO2 electrode, which would be accomplished in the present work. The tin dioxide electrode was produced by cathodic electrodeposition using a SnCl2·2H2O solution in the presence of HNO3 and NaNO3 on a graphite plate substrate. The impact of various operating parameters (current density - CD, HNO3 concentration, and SnCl2·2H2O concentration) on the morphology and structure of the SnO2 deposit layer was thoroughly investigated. The physical structures of the SnO2 film were determined by X-ray diffraction (XRD), surface morphology was characterized using field-emission scanning electron microscopy (SEM), and chemical composition was analyzed using energy-dispersive X-ray spectroscopy (EDX). In a batch reactor, the sonoelectrochemical oxidation of phenol was tested to determine the performance of the best SnO2 electrodes for phenol degradation and any organic byproducts. It was discovered that 10 mA/cm2, 50 mM of SnCL2·2H2O, and 250 mM of HNO3 were the optimum conditions to prepare SnO2 electrodes, which produced the smallest crystal size, with no appeared cracks, and gave the best phenol removal. The best prepared electrode was tested in the sonoelectrochemical oxidation of phenol with two different electrolytes and different CD, and the results showed that the phenol removal was 76.87% and 64.68% when using NaCl and Na2SO4, respectively, as well as was 63.39, 76.87, and 100% for CD at 10, 25, and 40 mA/cm2, respectively. [ABSTRACT FROM AUTHOR]

Due to their toxicity and persistence in the environment, phenolic pollutants pose a serious threat to the ecosystem. In this work, the performance of hydrophobic deep eutectic solvents (HDESs) for phenol removal from aqueous effluents is thoroughly investigated using COSMO-RS screening followed by experimental validation. The screening results of 73 HDESs showed that the efficacy of phenol removal is significantly affected by chain length, functional groups, and aromaticity. Trioctylphosphine oxide (TOPO)-based HDESs were found to be the most effective HDESs for phenol elimination combined either with menthol (Men), 1-hexanol (Hex), Decanoic acid (DecA), or Thymol (Thy) all in 1:1 molar ratios. The better phenol elimination abilities of the selected HDESs were confirmed by experimental LLE data obtained at 298.15 K and 101 kPa. In fact, it has been found that there is a positive correlation between extraction efficiency and phenol content. For instance, at a phenol concentration of 7%, TOPO:Men had the highest extraction efficiency (96%). Moreover, the physicochemical properties of the selected HDESs, such as density, viscosity, FTIR, 1HNMR, and TGA, were also measured. The results showed their high thermal stability and low water solubility, which makes them suitable for phenol extraction applications. This study shows that HDESs are capable of removing phenolic contaminants from aqueous effluents in a sustainable and efficient manner and that the selected TOPO-based HDESs are of particular interest for further research and application in phenol removal. [ABSTRACT FROM AUTHOR]

In the present work, Response Surface Methodology (RSM) was utilized to optimize process variables and find the best circumstances for indirect electrochemical oxidation of mimicked wastewater to remove phenol contaminants using prepared ternary composite electrode. The electrodeposition process is used for the synthesis of a ternary composite electrode of Mn, Co, and Ni oxides. The selected concentrations of metal salts of these elements were 0.05, 0.1, and 1.5 M, with constant molar ratio, current density, and electrolysis time of 1:1:1, 25 mA/cm2, and 2 h. Interestedly, the gathered Mn-Co-Ni oxides were deposited at both the anode and cathode. X-ray diffraction (XRD) and scanning electron microscopy (SEM) facilitated the qualitative characterization of surface structure and morphology of the accumulated oxides. The energy dispersive X-ray (EDX) provided a semi-quantitative analysis of deposit composition. The atomic force microscopy (AFM) apparatus quantified the roughness. We examined the efficiency of composite electrodes in coinciding with the removal of Chemical Oxygen Demand (COD) under current densities of 40, 60, and 80 mA/cm2, pH values of 3, 4, and 5, and NaCl concentrations of 1, 1.5, 2 g/l. RSM covered the optimization of process parameters in conjunction with Central Composite Design (CCD). The COD represented the response function in the optimization procedure. The optimal current density, NaCl concentration, and pH magnitude were 80 mA/cm2, 1.717 g/l, and 3, respectively. The efficiency of COD elimination of 99.925% attained after 1 hour of indirect electrochemical oxidation with an energy consumption of 152.380 kWh per kilogram of COD. The COD elimination model is significant based on the correlation coefficient (R2) and F-values, and the experimental data fitted well to a second-order polynomial model with R2 of 98.93%. [ABSTRACT FROM AUTHOR]

Phenolic compounds are commonly found in industrial effluents and can be hazardous to organisms even at low concentrations. Over the years, researchers have demonstrated that bioremediation is a cost-effective and environmentally friendly alternative to physicochemical approaches used to remove phenol. The aim of this study was to investigate the removal of phenol from saline wastewaters by a halotolerant strain of the genus Janibacter. For this purpose, bacterial cells were immobilized on different supports, from which mica and zeolite were ultimately chosen due to their higher removal efficiency. The wet weight of immobilized cells per 1 g of mica and zeolite was 0.51 and 0.48 g, respectively. Free cells consumed 100 mg/L of phenol in 88 h, while immobilized cells used it in 40 h. Immobilized cells revealed a higher thermostability and could operate over a wider pH range and salinity. Unlike free cells, immobilized cells could remove 700 mg/L of phenol and could be reused for at least nine cycles. Interestingly the phenol removal efficiency of zeolite-immobilized cells remained unchanged after 4 months of storage at 4 and − 20 °C, which could be of great advantage for industrial applications. Complete destruction of phenol was observed through the meta pathway comprising phenol hydroxylase and catechol 2,3-dioxygenase enzymes. Key points: • Mica- and zeolite-immobilized cells were able to consume high concentrations of phenol. • Cells immobilized on mica and zeolite had considerable operational and storage stability. • Immobilized cells could be a good candidate for phenol removal in saline environments. [ABSTRACT FROM AUTHOR]

In this study, the production of adsorbent from bituminous coal, which is directly treated with concentrated sulfuric acid, is investigated. The changes in the coal structure caused by the acid treatment are carried out by BET, FTIR and SEM analyzes and the adsorption capacities of the adsorbents are tested in phenol removal. According to the results of BET analysis, sulfuric acid treatment results in changes in the porous structure of original coal leading lower average pore diameters and higher surface areas. The phenol adsorption capacity of bituminous coal is increased considerably when a pretreatment procedure of washing and drying is included in the sulfuric acid treatment. While phenol removal efficiency of the original coal is only 7.64%, it reaches up to 78.56% after the treatment. The results of batch adsorption experiments also show that the inclusion of microwave and ultrasonic waves in the sulfuric acid treatment does not enhance phenol removal efficiencies. It is proposed that the most likely mechanism for phenol adsorption on bituminous coal is based on hydrogen bonding of phenolic hydroxyl with surface oxygen sites. Kinetic studies also demonstrate that the adsorption mechanism follows the pseudo second order kinetic model, which indirectly states that the rate limiting step is chemical sorption and adsorption rate is dependent on adsorption capacity. [ABSTRACT FROM AUTHOR]

Remarkably toxic, phenol requires efficient elimination from water. This study investigates the utilization of solid waste generated by stone-cutting factories for extracting phenol from wastewater. The solid waste underwent thermal treatment at 105 °C for 3 h for characterization. Batch adsorption experiments systematically assessed parameters like phenol concentration, adsorbent mass, contact time, temperature, and pH. Optimal removal transpired at pH 7.5, reaching equilibrium within 4 h. Phenol uptake equilibrium values were 8.1, 13.3, 16.2, 20.2, and 28.1 mg/g for initial concentrations of 50, 100, 150, 200, and 300 mg/L, respectively using 1 g of adsorbent at ambient temperature. The Langmuir model fit acceptably, yet the Freundlich model surpassed it. The most suitable kinetics model for phenol adsorption was the pseudo-second-order. The nature of the adsorption process was endothermic. Importantly, this study pioneers the promising application of solid waste generated from stone-cutting factories as an adsorbent material for effective phenol removal, offering a sustainable approach. Notably, no previous study has been conducted on phenol removal from wastewater using this specific adsorbent, rendering this work pivotal in exploring its potential. This solid waste presents an economical, readily available, and environmentally benign material for the adsorption process, expected to exhibit substantial adsorption capacity.

The aim of the study was to use regenerated activated carbon to adsorb phenol from a river. Coconut shell activated carbon was derived from used tap water filter cartridges. The activated carbon was carbonised and then activated with KOH at 200°C, under a nitrogen atmosphere. The resulting adsorbent was characterised on the basis of nitrogen adsorption by Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) analysis and point of zero charge (pH PZC). The study of periodic adsorption included kinetic and equilibrium modelling, determined the effect of solution pH on efficiency and the possibility of regeneration and reuse of the adsorbent. The efficiency of phenol removal from model water was evaluated, followed by the possibility of their adsorption from a polluted river in Silesia Province. Phenol adsorption followed pseudo-second-order kinetics. The adsorbents showed high adsorption abilities, as determined by the Langmuir isotherm model. The model fits the experimental data well. The concentration of phenol in the river was in the range of 0.45-0.77 mg·dm-3, which means that its value was at least five times higher than the standard values. The use of regenerated activated carbon from waste filter cartridges removed phenol from the river by 78% using optimal test parameters. [ABSTRACT FROM AUTHOR]

Peroxymonosulfate (PMS) activation has gained increasing attention for its water remediation. In this work, carbon nanotube-supported FeCo2O4 nanoparticles (FeCo2O4/CNT) were prepared and showed tremendous potential as a catalyst for PMS activation. The synergistic effect between FeCo2O4 and CNT in FeCo2O4/CNT promotes its better catalytic performance than individual CNT or FeCo2O4. The synthesized FeCo2O4/CNT could reach 100% phenol removal with a k value of 0.30 min−1 within 15 min ([PMS] = 0.3 g L−1, [FeCo2O4/CNT] = 0.3 g L−1). FeCo2O4/CNT can adapt well to a wide pH range (4–9) and a complex water component (with inorganic ions or organic matter). Moreover, the catalytic mechanism investigation suggested that both radical and non-radical pathways are accountable for the efficient removal of phenol. [ABSTRACT FROM AUTHOR]

Phenol contaminants are highly biotoxic and have become a global problem threatening the environment and human health. The objective of the present study was to develop a very efficient and easily recyclable adsorbent to remove phenol. A magnetic montmorillonite composite with organic co-intercalation was fabricated by a simple one-step co-precipitation method and exhibited excellent phenol removal. Two surfactants, cetyltrimethylammonium bromide (CTAB) and erucic acid amide (EA), were successfully co-intercalated into the interlayer of Ca-montmorillonite, and Fe3O4 nanoparticles were simultaneously decorated to obtain Fe3O4-CTAB/EA-montmorillonite composite (Fe3O4-C/E-Mnt). The morphology and structure of Fe3O4-C/E-Mnt composite were explored by using different techniques such as X-ray diffraction, Fourier-Transform infrared spectroscopy, X-ray photoelectron microscopy and so on. The adsorption capacity of Fe3O4-C/E-Mnt for phenol was investigated under various conditions including temperature, pH, contact time, various phenol concentrations, and adsorbent dosage. The results showed that Fe3O4-C/E-Mnt retained a lamellar structure of Ca-Mnt with mesopores. Its interlayer space, surface area, and pore volume were increased. The Fe3O4-C/E-Mnt composite exhibited a good adsorption capacity (31.45 mg·g–1) for phenol with a removal efficiency of 85.46% at optimized conditions. Moreover, the adsorbent still maintained 78.32% of the adsorption capacity after five cycles. The adsorption test data of Fe3O4-C/E-Mnt followed the pseudo-second order kinetic model and the Langmuir model. The adsorption was a spontaneous, exothermic, entropy-decreasing process, and a possible adsorption mechanism of Fe3O4-C/E-Mnt was finally proposed. [ABSTRACT FROM AUTHOR]

The ozonation reaction in a bubble column reactor (BCR) has been widely used in the removal of phenol from wastewater, but the phenol removal efficiency in this type of reactor is limited because of low ozone solubility and reactivity in the system. In the present study, the phenol degradation in the BCR was enhanced by using α-Al2O3 as a packing material and a ZnO nanocatalyst. The reactor diameter and height were 8 cm and 180 cm, respectively. The gas distributor was designed to include 52 holes of a 0.5 mm diameter. Also, the gas holdup, pressure drop, and bubble size were measured as a function of the superficial gas velocity (i.e., 0.5, 1, 1.5, 2, 2.5, and 3 cm/s). The evaluation of the hydrodynamic parameters provided a deeper understanding of the ozonation process through which to select the optimal operating parameters in the reactor. It was found that the best superficial gas velocity was 2.5 cm/s. A complete (100%) phenol removal was achieved for phenol concentrations of 15, 20, and 25 ppm at reaction times of 80, 90, and 100 min, respectively; this was achieved by using α-Al2O3 packing material and a ZnO nanocatalyst in the BCR. Additionally, a reaction kinetics study was conducted to describe the ozonation reaction in BCR. The first-order reaction assumption clearly describes the reaction kinetics with an R2 = 0.991. Finally, the applied treatment method can be used to efficiently remove phenol from wastewater at a low cost, with a small consumption of energy and a simple operation. [ABSTRACT FROM AUTHOR]

In the ozonation process, the phenol degradation in wastewater undergoes a low mass transfer mechanism. In this study, ozonized packed bubble column reactor was designed and constructed to remove phenol. The reactor’s inner diameter and height were 150 and 8 cm, respectively. The packing height was kept constant at 1 m in accordance with the reactor hydrodynamics. The gas distributor was designed with 55 holes of 0.5 mm. The phenol removal efficiency was evaluated at ozone concentrations of 10, 15, and 20 mg/L, contact times of 15, 30, 45, 60, 75, 90, 105, and 120 min, and phenol concentrations of 3, 6, 9, 12, and 15 mg/L. The results indicated that the highest phenol removal efficiency of 100% was achieved at 30 min in presence of packing. Moreover, the use of packing improved the contact between the gas and liquid, which significantly enhanced the phenol degradation. Actually, a thin film over a packing surface enhances the mass transfer. Also, it was found that the phenol is degraded into CO2 and H2O through a series of reaction steps. Additionally, a kinetic study of a first-order reaction provided an efficient estimation of reaction parameters with a correlation factor of 0.997.

Microbial-mineral interaction has a broad application prospect in the field of environmental remediation of organic pollutants. However, the disadvantages of long repair cycle and low repair rate limit its industrial application. In this study, natural hematite was used as an auxiliary material for soil remediation in a bio-electrochemical system. It was found that the power density of soil microbial fuel cell (SMFC) system composed of 2.0 mm hematite was 2.889 mW/m2, which is 2.7 times compared with the blank group (1.068 mW/m2) in the particle size optimization experiment. A similarly increased power density (1.068 to 2.467 mW/m2) was observed when the hematite content changed from 0 to 20% in the concentration optimization experiment. Under 20% and 2.0-mm hematite condition, the phenol removal rate was closed to 99% after 7 days, which is 1.9-folds compared with blank control (53%). These results suggest that addition of hematite enhances soil porosity and conductivity, and increases the number of electron acceptors in soil. These findings inspire that this economic and abundant natural mineral is expected to be a potential auxiliary material in the field of soil organic pollutant purification, and expand the understanding of interactions between hematite and microorganisms in nature. [ABSTRACT FROM AUTHOR]

Phenolic chemicals are poisonous and have long-term impacts on humans and animals. Even in low quantities, as carcinogens, they destroy red blood cells and the liver. These biological waste products pollute groundwater. Thus, removing these organic chemicals to meet discharge limits is difficult. Electrochemical oxidation, redox reactions, membrane separation, and photocatalytic degradation help remove phenolic chemicals from water. Recently, phenolic chemicals have been shown to be removed via adsorption and photocatalysis employing carbon materials and clays. Due to their unique chemical and physical properties, nanometric materials are crucial to these processes. These substances' structures, classification, entry points, and reactivity or interaction with other aquatic components have been extensively studied. Phenolic substances can be removed from the water before usage. This has led to the development of water treatment technologies and methods like activated carbon adsorption, solvent extraction, the electro-Fenton method, membrane-based separation method, photocatalysis, and others that have been shown to successfully remove phenolic compounds from water. Activated carbon is the most promising adsorbent for numerous contaminants (dyes, metals, etc.). However, low-cost agricultural materials are typically used to switch to more environmentally friendly ones. This study uses low-cost, eco-friendly adsorbents to remediate biomedical effluents. Pyrolysis of potato peels (waste) from a restaurant produced carbon samples. Absorption–desorption experiments examined pH, temperature, starting drug concentration, contact time, and regeneration ability. [ABSTRACT FROM AUTHOR]

Phenols are commonly encountered in the aqueous effluents of different industrial processes, such as oil refining, and phenolic resin manufacturing and processing. Because phenols are toxic, they should be promptly removed from aquatic environments. Herein, we describe the preparation of photocrosslinked β-cyclodextrin (β-CyD) polymer beads and their use for the removal of phenol (PhOH) from the raw industrial wastewater from phenolic resin processing. Polysubstituted photocrosslinkable β-CyD (PSβCyD/UV) sorbent beads were obtained via the reaction of globed macromonomers with sodium alginate and calcium chloride followed by photocrosslinking the β-cyclodextrin (β-CyD) macromonomers with isophorone diisocyanate and 2-hydroxyethyl acrylate (molar ratio of 1:3.5:3.5). The physical properties of the fabricated PSβCyD/UV beads were as follows: average diameter, 2.7 mm; average compressive strength, 6.5 M Pa; porosity, 41.4%; and specific surface area, 2.89 m2/g. The removal of PhOH from raw industrial wastewater using β-CyD polymer beads was performed in a shaker at 25 °C. After six accumulated adsorption cycles, the PhOH concentration decreased from of 89,000 to 1500 mg/L; furthermore, the expansion factor of PSβCyD/UV was 1.33. Adsorbent PSβCyD/UV polymer beads with a regular spherical shape and high mechanical stability were prepared using a photocrosslinking method. The results of the sorption experiments indicated that the PhOH adsorption capacity of the polymer beads from raw industrial wastewater was high (2.43 mmol/g-resin). We concluded that the prepared polymer beads formed rich polymer network structures, which affected the physical adsorption of PhOH and the chemical interactions with PhOH via hydrogen bonding. [ABSTRACT FROM AUTHOR]

Due to their toxicity and persistence in the environment, phenolic pollutants pose a serious threat to the ecosystem. In this work, the performance of hydrophobic deep eutectic solvents (HDESs) for phenol removal from aqueous effluents is thoroughly investigated using COSMO-RS screening followed by experimental validation. The screening results of 73 HDESs showed that the efficacy of phenol removal is significantly affected by chain length, functional groups, and aromaticity. Trioctylphosphine oxide (TOPO)-based HDESs were found to be the most effective HDESs for phenol elimination combined either with menthol (Men), 1-hexanol (Hex), Decanoic acid (DecA), or Thymol (Thy) all in 1:1 molar ratios. The better phenol elimination abilities of the selected HDESs were confirmed by experimental LLE data obtained at 298.15 K and 101 kPa. In fact, it has been found that there is a positive correlation between extraction efficiency and phenol content. For instance, at a phenol concentration of 7%, TOPO:Men had the highest extraction efficiency (96%). Moreover, the physicochemical properties of the selected HDESs, such as density, viscosity, FTIR, 1HNMR, and TGA, were also measured. The results showed their high thermal stability and low water solubility, which makes them suitable for phenol extraction applications. This study shows that HDESs are capable of removing phenolic contaminants from aqueous effluents in a sustainable and efficient manner and that the selected TOPO-based HDESs are of particular interest for further research and application in phenol removal.

Phenols are considered serious contaminants because even at low concentrations, they are toxic and characteristics due to their toxic and carcinogenic properties. Removing the phenols from industrial effluents water before entering a stream is highly recommended Ni/ZIF-8 was used in a batch process to adsorb phenol from aqueous solutions at different temperatures. The operating conditions were considered as temperature, contact time, and initial pollutant concentration. The adsorption isotherms at different temperatures were determined based on three different models. For temperature range 25–40 oC, the best-fitting adsorption isotherm models were Freundlich > Langmiur > Temkin. It was found that the Langmuir model fits the experimental data well, with maximum adsorption capacities of 36.8 mg/g at 25, 25.9 mg/g at 40 and 22.4 mg/g at 60 °C. According to the results of thermodynamic analysis, the adsorption of phenol onto zeolite is physical and exothermic. The Ni/ZIF-8 adsorbent proved to be effective in removing phenol by adsorption.

The ceramic separator has been interested in low-cost alternative proton exchange membranes in a microbial fuel cell (MFC). In this study, the silica-modified ceramic separator has been integrated with the yeast-based MFC for electricity generation and phenol treatment from the winery wastewater. The 30% (w/w) silica powder was mixed with the 70% (w/w) natural clay. The modified ceramic plates (0.2, 0.5, and 1.0 cm of thickness) were prepared at 680°C and used for MFC operation. As an anolyte, synthetic winery wastewater (2,000 mg COD/L and 100 mg/L phenol) with 5% (v/v) ethanol was used. The ethanol-tolerant yeast Pichia sp. ET-KK was used as an anodic catalyst. The results showed the maximal power density of 0.212 W/m2 and phenol removal of 95.05% were reached from the 0.2-thick ceramic plate integrated MFC. This study demonstrated that the silica-modified ceramic separator has a high potential for enhancing electricity generation in the yeast-based MFC.

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]

Phenol is a vicious contaminant due to its high toxicity and potential for accumulating in the environment. This ubiquitous organic pollutant gets introduced to the surface water through the effluents of various industries such as industrial coal conversion, fertilizers, petroleum refineries, coke oven plants, pharmaceutical, dye processing, etc. Since presence of even a smaller concentration of phenolic compounds is a serious threat to the living organisms, elimination of this hazardous material from the waste water prior to its discharge is utmost necessary. To mitigate this challenge, numerous techniques have been employed till date, of which, adsorption method has emerged as a promising processing candidate. The method has gained tremendous attention due to the use of natural adsorbents (or biosorbent) specifically derived from the agricultural or household residues. The wide availability, low cost, environmental friendliness and excellent biodegradability of the biosorbent not only enhances the efficacy but also dictates the simplicity and versatility of this technique. The current research deals with the actively removal of phenol concentration from real coke wastewater using activated carbon extracted from banana peel waste as an adsorbent. The maximum phenol removal efficiency from coke wastewater was achieved by batch study with varying parameters at 100 min equilibrium contact time, pH: 7, and adsorbent dosage 0.5 g/30 mL. The parameters such as the adsorbent dose (A: 0.1–1 g), pH (B: 2–10), and temperature (C: 25–50°C) were optimized and statistically analyzed by using Box Behnken design (BBD). The use of activated banana peel biosorbent resulted to achieve maximum phenol removal efficiency of 89.22%. The detailed characterization of biosorbent was corroborated by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and the surface area were analyzed by Brunauer–Emmett Teller (BET). The adsorption data were analyzed and fitted well with the Temkin adsorption isotherm and pseudo-second-order kinetic model. The thermodynamic study indicates that the phenol adsorption on to banana peel biosorbent was an endothermic and physio-sorption process. [ABSTRACT FROM AUTHOR]

• Phenol removal, biomass productivity and lipid were maximized using BBD. • Phenol enhanced lipid productivity ∼ 1.6-folds higher than the control. • Saturated and polyunsaturated fatty acids were increased under phenol treatment. • Biodiesel characteristics were investigated. There is a growing interest for the utilization of microalgae in the bioremediation of organic pollutants and the use of biomass as a biofuel feedstock. This study investigated the influence of phenol exposure and culture conditions on the phenol removal efficiency, biomass productivity and lipid contents of Tetradesmus obliquus. Plackett-Burman design identified CaCl 2 , NaNO 3 , and initial phenol concentration as the most important variables affecting on phenol removal. The optimum conditions to maximize biomass productivity, phenol removal and lipid content were determined using the Box-Behnken experimental design as 150.1 mg L−1 phenol, 0.1 g L−1 NaNO 3 , and 0.03 g L−1 CaCl 2. Under these conditions, phenol was completely removed from the optimized medium after 3 days and the biomass productivity and lipid content were 19.53 mg L−1 day−1 and 27.85% (w/w) after 10 days, respectively. Phenol treatment promoted algal biomass productivity to ∼1.3-folds and lipid productivity to ∼ 1.6-folds higher than the control treatment without adding phenol (negative control). Additionally, phenol altered the fatty acid methyl ester composition and increased the saturated and polyunsaturated fatty acid contents with concomitant decrease in the monounsaturated fatty acids. The predicted biodiesel characteristics viz. iodine value, cetane number, oxidation stability, kinematic viscosity, and flash point, in the presence of phenol were in accordance with the international standards. Accordingly, the present study indicated that phenol could be effectively bioremediated by T. obliquus with simultaneous promotion of the algal biomass and lipid productivity for biofuel production. [ABSTRACT FROM AUTHOR]

The sub-micrometer sized TiO 2 particles (100–200 nm) were synthesized by a sol-gel and subsequent thermal annealing. The particle size, surface area, pore structure, and crystallinity were varied upon the annealing temperatures (450, 550, 650 °C). The photocatalytic activities of three TiO 2 particles annealed at various temperatures (450-, 550-, and 650-TiO 2) were examined by performing photocatalytic depollution of three organic model pollutants (methylene blue, methyl orange, and phenol) from aqueous solutions under the UV light irradiation. Among three samples, 550-TiO 2 (~200 nm) exhibited the highest photocatalytic activity towards the removals of all three model pollutants. Photocatalytic activity of the 550-TiO 2 was compared with a commercial TiO 2 (P25, Evonik) at various conditions of loading amounts of particles dispersed in MB solution. Light scattering by dispersed particles at high sample loading conditions was less pronounced in the case of 550-TiO 2. Therefore, the sub-micro 550-TiO 2 particles can exhibit comparable activity to P25 at high sample loading conditions (2–4 g/L). In addition, the bigger size of 550-TiO 2 made it possible to separate them via a simple sedimentation process, showing a potential of sub-micro TiO 2 particles as an efficient photocatalysts for water depollution. [Display omitted] [ABSTRACT FROM AUTHOR]

Peroxymonosulfate (PMS) activation has gained increasing attention for its water remediation. In this work, carbon nanotube-supported FeCo2O4 nanoparticles (FeCo2O4/CNT) were prepared and showed tremendous potential as a catalyst for PMS activation. The synergistic effect between FeCo2O4 and CNT in FeCo2O4/CNT promotes its better catalytic performance than individual CNT or FeCo2O4. The synthesized FeCo2O4/CNT could reach 100% phenol removal with a k value of 0.30 min−1 within 15 min ([PMS] = 0.3 g L−1, [FeCo2O4/CNT] = 0.3 g L−1). FeCo2O4/CNT can adapt well to a wide pH range (4–9) and a complex water component (with inorganic ions or organic matter). Moreover, the catalytic mechanism investigation suggested that both radical and non-radical pathways are accountable for the efficient removal of phenol.

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]

The modified abandoned fine blue-coke (MAFB) was used to remove phenol from the aqueous solution efficiently. The effects of initial concentration, temperature, pH, and co-existing salt ions of the phenol solution on the adsorption capacity of MAFB for phenol were investigated. The adsorption equilibrium, thermodynamic, kinetic, and adsorbent regeneration were studied simultaneously. The results showed that the maximum adsorption capacity of phenol onto the MAFB was obtained as 151.74 mg g−1 at the initial solution concentration of 1100 mg L−1, the temperature of 328 K, and pH of 4.0–6.5. The salt ions of Na+, Cl−, SO2-4 had little effect on the adsorption capacity. The adsorption isotherm belongs to the L isotherm and the Langmuir model can better describe the adsorption process. Thermodynamics results indicated that the adsorption was entropy increase, spontaneous and endothermic process. The adsorption kinetics was found to follow the pseudo-second-order model. The physical adsorption of π–π dispersion interactions could be used to describe the adsorption mechanism. The 60% regeneration rate of the MAFB was reached by three times alcohol desorption at 323 K for 4 h. Compared with other adsorbents, MAFB has better phenol adsorption performance, which makes it a promising and excellent adsorbent to remove phenol from wastewater. [ABSTRACT FROM AUTHOR]

The utilization of biochar, prepared from the agricultural biomass, is one of the economic approaches. To assess the ability of biochar as an adsorbent, sugarcane bagasse-derived biochar was utilized for the removal of phenol from aqueous solution. Phenol, an industrial discharge and a ubiquitous organic pollutant, was chosen as the model compound to determine the adsorption capacity of sugarcane bagasse-derived biochar. The sugarcane bagasse was pyrolyzed at 400, 600, and 800 °C under an N2 atmosphere. Among all the three raw biochars, the biochar obtained at 600 °C showed maximum removal efficiency, 74.2%. Based on higher efficiency, SB-600 biochar was further chemically treated with nitric acid (HNO3) and sodium hydroxide (NaOH) to enhance its adsorption capacity. Sugarcane bagasse-derived magnetic biochar was also fabricated using the pre-pyrolysis modification. Maximum removal (96.1%) efficiency was observed in the case of HNO3-treated calcined biochar compared to the other treated biochars. Adsorption parameters of the calcined-acid treated biochar were optimized through response surface methodology. The maximum adsorption capacity of the calcined-acid treated biochar was 41.3 mg/g. [ABSTRACT FROM AUTHOR]

Phenolic chemicals are poisonous and have long-term impacts on humans and animals. Even in low quantities, as carcinogens, they destroy red blood cells and the liver. These biological waste products pollute groundwater. Thus, removing these organic chemicals to meet discharge limits is difficult. Electrochemical oxidation, redox reactions, membrane separation, and photocatalytic degradation help remove phenolic chemicals from water. Recently, phenolic chemicals have been shown to be removed via adsorption and photocatalysis employing carbon materials and clays. Due to their unique chemical and physical properties, nanometric materials are crucial to these processes. These substances’ structures, classification, entry points, and reactivity or interaction with other aquatic components have been extensively studied. Phenolic substances can be removed from the water before usage. This has led to the development of water treatment technologies and methods like activated carbon adsorption, solvent extraction, the electro-Fenton method, membrane-based separation method, photocatalysis, and others that have been shown to successfully remove phenolic compounds from water. Activated carbon is the most promising adsorbent for numerous contaminants (dyes, metals, etc.). However, low-cost agricultural materials are typically used to switch to more environmentally friendly ones. This study uses low-cost, eco-friendly adsorbents to remediate biomedical effluents. Pyrolysis of potato peels (waste) from a restaurant produced carbon samples. Absorption–desorption experiments examined pH, temperature, starting drug concentration, contact time, and regeneration ability.

The review centred on the existence of phenol, which is a widespread organic pollutant. It is crucial to study it owing to its toxic effects, even at low concentrations, and the high likelihood of contaminating natural waters, in addition to wastewater from agricultural wastewater or urban wastewater. To make matters worse, it contributes to substance formation during the process of disinfection and oxidation. It is also common practice to dump commercial wastewater which has nearly identical characteristics to urban wastewater into community sewers. Various methods have been explored for eliminating the phenolic compound. This report has concentrated on phenol degradation through aerobic pathways and anaerobic pathways as well as numerous microorganisms involved in the degradation of the phenols. [ABSTRACT FROM AUTHOR]

In the course of this research, the potential of activated carbon from rice husk was examined as being a phenol removal medium from an aqueous solution in a fixed-bed adsorption column. The activated carbon was characterized through FESEM (Field-Emission Scanning Electron Microscopy) and BET (Brunauer–Emmett–Teller) surface area. According to the FESEM micrograph and BET surface area, RHAC (rice husk activated carbon) had a porous structure with a large surface area of 587 m2·g−1 and mean diameter of pores of 2.06 nm. The concentration effects on the influent phenol (100–2000 mg·L−1), rate of flow (5–10 mL·min−1), and bed depth (8.5–15.3 cm) were examined. It was found that the capacity of bed adsorption increased according to the increase in the influent concentration and bed depth. However, the capacity of bed adsorption decreased according to the increase in the feed flow rate. The regeneration of activated carbon column using 0.1 M sodium hydroxide was found to be effective with a 75% regeneration efficiency after three regeneration cycles. Data on adsorption were observed to be in line with many well-established models (i.e., Yoon–Nelson and Adams–Bohart, as well as bed depth service time models). [ABSTRACT FROM AUTHOR]

Developing a multi-functional green energy device that propels sustainable energy development and concurrently purifies environmental pollutants offers an irresistibly compelling vision for a cleaner future. Herein, we reported a bias-free glucose/O 2 bio-photoelectrochemical system (BPECS) for both energy conversion and phenolic pollutants degradation. Coupling a glucose dehydrogenase (GDH) modified self-assembled meso-tetrakis (4-carboxyphenyl)-porphyrin (SA-TCPP)-sensitized TiO 2 biophotoanode for glucose oxidation and nitrogen/oxygen doped cobalt single-atom catalyst (CoNOC) cathode for two-electron oxygen reduction, both solar and biochemical energies were converted into electric power in BPECS with a maximum power density of 296.98 μW cm−2 (0.49 V). Working in synergy with horseradish peroxidase (HRP) biocatalysis, the cathode-generated H 2 O 2 , a by-product, is effectively redeployed for degrading phenol, attaining an impressive degradation efficiency of approximately 100% within 60 min. Additionally, aiming to scale up this ingenious BPECS approach, peroxidase-mimicking Co 3 O 4 nanozyme were engineered as a substitute for natural HRP. Remarkably, these nanozyme demonstrated a comparable degradation efficiency, achieving the same result in 90 min. In this work, our results demonstrate that this bias-free glucose/O 2 BPECS model marks a significant step forward in integrating renewable energy harvesting with environmental remediation, but also opens new avenues for the versatile application of nanozymes. [Display omitted] • As a multi-energy conversion platform, BPECS converts both solar and bio-chemical energies into clean electric power. • Leveraging by-product of H 2 O 2 in BPECS, HRP-biocatalyzed phenol degradation achieves nearly 100% efficiency within 60 min. • Replacing natural HRP with Co 3 O 4 nanozymes, the nanozyme-assistant BPECS achieves nearly 100% phenol degradation efficiency within 90 min. • This designed BPECS propels sustainable energy development, purifies environmental pollutants and concurrently opens new avenues for the versatile application of nanozymes. [ABSTRACT FROM AUTHOR]

• Kaolin was successfully developed as an efficient phenol adsorbent with a maximum percentage removal of 92.19 %. • The optimum conditions obtained were at pH 1.6, 40 mins, 50 mg/L initial phenol concentration, and 2 g of kaolin. • The adsorption phenol onto kaolin process fit Freundlich isotherm and Pseudo Second Order kinetic model. • QTAIM and RDG-NCI analyses revealed that kaolin removes phenol due to the hydrogen bonding interaction. • The Frontier Molecular Orbital (FMO) reveals mechanistic insight into phenol adsorption. The discharge of phenols into the aquatic environment has detrimentally affected human health and the aquatic ecosystem. Hence, removing phenols from polluted water bodies has been a global concern. In this study, a natural and low-cost adsorbent, kaolin, was used to remove phenol from aqueous solutions. Experimental and computational approaches were applied to optimize the removal efficiency and provide mechanistic insight into the phenol removal process. Based on the response surface methodology findings, the optimum conditions were pH 1.6, 40 min, 50 mg/L, and 2 g with 92.19 % maximum percentage removal. The regeneration test shows that kaolin retained over 76.76 % of adsorption capacities. SEM and FESEM reveals the surface morphology and effectiveness of kaolin as phenol removal. The best fit for the Isotherm adsorption for the phenol on kaolin is Freundlich isotherm, which indicated multilayer adsorption. The hydroxyl group from phenol (-OH) and the siloxane group of kaolin (Si-O-Si) shifted, suggesting the presence of a hydrogen bond between kaolin and phenol during adsorption, as determined by one- and two-dimensional IR spectroscopy. Density functional theory calculations were used to support the experimental results by providing information on the Mulliken charge and electronic transition of the complex to improve understanding of the adsorption of phenol on kaolin. Based on the quantum theory of atoms in molecules analysis (QTAIM) and the reduced density gradient non-covalent interaction (RDG-NCI) technique, the chemical reaction occurring during the removal of phenol by kaolin was determined to occur through hydrogen bonding and classified as an intermediate type (∇2ρ(r) > 0 and H < 0). Further characterizations employing molecular electrostatic potential, global reactivity, and local reactivity descriptors were conducted to investigate the mechanism of the phenol adsorption on kaolin. The findings demonstrated that phenol functions as an electrophile while kaolin acts as a nucleophile during the formation of hydrogen bonds, where the interaction occurred between the O 2 atom of kaolin (electron donor) and the H13 atom of phenol (electron acceptor). [Display omitted] [ABSTRACT FROM AUTHOR]

The treatment efficiency of acidic phenol-containing wastewater is hindered by the absence of efficient acid-resistant phenol-degrading bacteria, and the acid-resistant mechanism of such bacteria remains poorly studied. In this study, the acid-resistant strain Hly3 was used as a research model to investigate its ability to degrade phenol and its underlying mechanism of acid resistance. Strain Hly3 exhibited robust acid resistance, capable of surviving in extremely acidic environments (pH 3) and degrading 1700 mg L−1 phenol in 72 h. Through the physiological response analysis of strain Hly3 to pH, the results indicated: firstly, the strain could reduce the relative permeability of the cell membrane and increase EPS secretion to prevent H+ from entering the cell (shielding effect); secondly, the strain could accumulate more buffering substances to neutralize the intracellular H+ (neutralization effect); thirdly, the strain could expel H+ from the cell by enhancing H+-ATPase activity (pumping effect); finally, the strain produced more active scavengers to reduce the toxicity of acid stress on cells (antioxidant effect). Subsequently, combining liquid chromatography-mass spectrometry (LC-MS) technology with exogenous addition experiments, it was verified that the acid resistance mechanism of microorganisms is achieved through the activation of acid-resistant response systems by glutamine, thereby enhancing functions such as shielding, neutralization, efflux, and antioxidation. This study elucidated the acid resistance mechanism of Acinetobacter pittii , providing a theoretical basis and guidance for the treatment of acidic phenol-containing wastewater. [Display omitted] • The acid-resistant mechanism of Acinetobacter pittii was explained for the first time. • Hly3 can survive in extremely acidic conditions and degrade phenol efficiently (pH 3, 72 h, 1700 mg L−1). • Four pathways (shielding, neutralizing, effluxing, and antioxidant) may contribute to microbial acid resistance. • Glutamine metabolism activates the activity of Hly3 acid-resistant reaction system. [ABSTRACT FROM AUTHOR]

The study focused on the production of the tyrosinase enzyme from Streptomyces sp. MR28 and its potency in removal of phenol content from water using free and immobilized tyrosinase enzyme. The tyrosinase was produced by Streptomyces sp. MR28 in liquid tyrosine broth medium, and it was further purified to near its homogeneity by employing, precipitation, dialysis, and column chromatography. After the purification, 44.49% yield with a 4 fold purification was achieved. The characterization of the purified enzyme showed a single major peak on HPLC and a solitary band on SDS-PAGE. The purified tyrosinase enzyme was active at a pH of 7.0 and a temperature of 30 °C. Further immobilization of purified tyrosinase was performed using the sodium alginate entrapment method. The capacity of the purified tyrosinase to remove phenol in water was evaluated by spectrophotometric method. The free tyrosinase enzyme-treated solutions showed a gradual decrease in the concentration of phenol with increased incubation time at 30 °C and 40 °C, at 90 min of the incubation time, it showed maximum efficacy in removing phenol from the solution. At 50 °C and 60 °C, the free tyrosinase enzyme exhibited very less capacity to remove the phenol. The immobilized enzyme showed good capacity for the removal of phenol from the solutions; the concentration of phenol in the solution decreased with an increase in the incubation time. At temperatures of 40 °C and 50 °C, the immobilized tyrosinase enzyme beads showed significant removal of phenol from the solution, and at temperatures of 30 °C and 60 °C, they also exhibited good capacity for the removal of phenol. At the end of the 90 min incubation period, it exhibited good capability. The current study suggests using immobilized microbial tyrosinase enzyme can be used for the removal of phenol from the contaminated water in a greener manner. • Tyrosinase was produced from Streptomyces sp. MR28 in modified tyrosine broth with optimum conditions. • The purification was conducted through precipitation, dialysis and column chromatography. • The purified tyrosine enzyme characterized by SDS-PAGE and HPLC analysis. • Purified tyrosinase was immobilized using sodium alginate method. • The immobilized tyrosinase exhibited significant phenol removal efficacy from water. [ABSTRACT FROM AUTHOR]

The separation and recovery of phenolic compounds from wastewater have both economic and practical significance. In this study, polymer inclusion membranes (PIMs) were developed using binary mixed carriers containing trioctylmethylammonium chloride (Aliquat 336) and tributyl phosphate (TBP), and poly(vinyl) chloride (PVC) as the base polymer for the recovery of phenolic compounds from aqueous solutions. The use of mixed carriers Aliquat 336 + TBP enhanced the extractability and transport efficiency of phenol, indicating the presence of synergism. The optimal results of this work showed that the maximum of transport fluxes (J S max or -J M max) increased from 0.097 (h−1) using the PIM composed of 40 wt% PVC and 60 wt% Aliquat 336, to 0.143 (h−1) using the PIM composed of 40 wt% PVC + 40 wt% Aliquat 336 + 20 wt% TBP. The addition of TBP eliminated the retention of the extracted Aliquat 336-phenol complexes in the membrane by forming an adduct with extracted species. The extraction/stripping efficiencies of 93.5%/83.8% and the permeability coefficient of 5.88 μm s−1 were obtained. The PIM containing synergistic mixed carriers could be recycled at least 15 times. [Display omitted] • Both permeability and stability can be enhanced by using mixed carriers. • The excellent synergistic effect occurs with mixed 40% Aliquat 336 and 20% TBP. • Evaluation of synergism and comprehensive analysis of factors that influenced it. • TBP decreased the interaction intensity between Aliquat 336 and phenol within PIM. • TBP eliminates the retention of the extracted complexes in the membrane. [ABSTRACT FROM AUTHOR]

Phenols are considered serious contaminants because even at low concentrations, they are toxic and characteristics due to their toxic and carcinogenic properties. Removing the phenols from industrial effluents water before entering a stream is highly recommended Ni/ZIF-8 was used in a batch process to adsorb phenol from aqueous solutions at different temperatures. The operating conditions were considered as temperature, contact time, and initial pollutant concentration. The adsorption isotherms at different temperatures were determined based on three different models. For temperature range 25-40 oC, the best-fitting adsorption isotherm models were Freundlich > Langmiur > Temkin. It was found that the Langmuir model fits the experimental data well, with maximum adsorption capacities of 36.8 mg/g at 25, 25.9 mg/g at 40 and 22.4 mg/g at 60 °C. According to the results of thermodynamic analysis, the adsorption of phenol onto zeolite is physical and exothermic. The Ni/ZIF-8 adsorbent proved to be effective in removing phenol by adsorption. [ABSTRACT FROM AUTHOR]

The membranes based on cellulose acetate (CA) were obtained by the method of phase inversion and used for removal of phenol (in concentrations of 15 and 25 mg/L) from liquid phase. To differentiate the hydrophilic properties of the membrane surfaces, different amounts of cellulose acetate (14 and 18 wt. %) and polyvinylpyrrolidone as a pore-generating agent (PVP, 1, 2, 3 or 4 wt. %) were used. The membranes were characterised by determination of their porosity, equilibrium water content, wetting angle and content of surface oxygen functional groups. After the application of membranes to phenol removal, the following parameters characterising the process were determined: permeability, membrane resistance, coke resistances, pore resistances, total filtration resistance and flux recovery ratio. The membranes were found to show higher effectiveness in phenol removal from a solution of the initial concentration 15 mg/L, and more effective were the membranes with higher contents of cellulose acetate. On the surface of the membranes the oxygen functional groups of acidic nature are dominant, both before and after filtration. The membranes of higher contents of cellulose acetate show higher resistances. [ABSTRACT FROM AUTHOR]