Initial Phenol Concentration Research Articles

Enhanced persulfate-assisted photocatalytic degradation of phenol by Ag/ZnFe2O4 composite

Effective and reasonable degradation of phenolic wastewater has important practical significance in reducing environmental pollution and ensuring water resource security. Ag/ZnFe2O4 (Ag/ZFO) photocatalysts were synthesized using the one-step solvothermal method and characterized by XRD, SEM, TEM, FT-IR, XPS, UV–vis DRS, and so on. Their photocatalytic performance for phenol degradation under visible light, assisted by persulfate (PS), was studied. The incorporation of Ag nanoparticles into ZFO significantly enhanced phenol degradation efficiency, especially 10 %Ag/ZFO showing the most remarkable improvement with 94.3 % phenol degradation in 60 min, —48.7 % higher than pure ZnFe2O4. The influence of various variables, including PS dosage, initial phenol concentration, solution pH, and common inorganic anions in water, on phenol degradation were examined systematically. The superior persulfate-assisted photocatalytic performance of 10 %Ag/ZFO, assisted by PS for phenol degradation, is primarily due to the surface plasmon resonance (SPR) effect of Ag nanoparticles, enhancing light absorption and use while inhibiting the photogenerated carriers’ recombination rates. In addition, Ag nanoparticles and the Fe3+/Fe2+ recycling redox process activate PS to produce more free radicals, thus improving the performance of the Vis-10 %Ag/ZFO-PS system for phenol degradation. The possible mechanism of the Vis-10 %Ag/ZFO-PS system for phenol degradation is described based on trapping tests, EPR, and XPS results. Magnetic retrievability, good structural stability, and high activity of the synthesized Ag/ZFO photocatalyst elucidate its potential application for degradation of phenolic wastewater.

Adsorption of ortho-Nitrophenol from Aqueous Solution using Phosphated Biomass of Ailanthus excelsa: Kinetic and Equilibrium Studies

This study interprets phosphated biomass of Ailanthus excelsa (PBAE) as a eco-friendly, inexpensive and potential adsorbent for adsorption of ortho-nitrophenol (ONP) from aqueous solution by using batch adsorption method. The prepared biosorbent was characterized using a variety of techniques such as Brunauer Emmett Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). As a function of many process parameters including material dose, contact time, concentration, pH and temperature, batch studies were conducted. It was found that a pH of 6.0, a biosorbent dosage of 0.050 g and an initial phenol concentration of 25 mg/L and temperature 298 K were the best conditions for ONP removal. The maximum sorption was found to be 95.28%. Adsorption data was better fitted to the Langmuir, Freundlich, Temkin and Dubinin Radushkevich isotherms. It was demonstrated that the sorption rate follows the pseudo-second order kinetics and intraparticle diffusion theory and the biosorption process was spontaneous and exothermic in nature.

A study on the application of a composite MIL88A(Fe)/TiO2 in a hexagonal photoreactor for phenol removal: Response surface methodology and kinetic modeling

AbstractThe application of a novel composite MIL88A(Fe)/TiO2 for phenol removal in a new hexagonal photoreactor design was investigated. The unique hexagonal shape of the reactor increases the surface area available for irradiation, leading to more efficient removal of contaminants. The composite was characterized using X ray diffraction (XRD), Fourier transform‐infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) images to determine its properties. Photocatalyst dosage, reaction time, phenol concentration, pH, and mL H2O2/L PW (phenol wastewater) were chosen as effective parameters on the process. To plan an experiment and maximize phenol removal, the response surface methodology (RSM) was applied. Ideal conditions for optimum efficiency (95.96%) include initial phenol concentration of 58 mg/L, pH of 7.51, reaction time of 68.61 min, mL H2O2/L PW of 0.18, and catalyst dosage of 0.4 g/L PW. Trapping experiments prove that ˙O2 and ˙OH produced in Fenton and photocatalytic processes are the predominant active radicals in this process. The kinetics was fitted with the first‐order, second‐order, n‐order, and Langmuir–Hinshelwood models using nonlinear least squares techniques. The n‐order model with n = 0.54 was found to be the most suitable model (R2 0.998), with a model constant of k = 0.11 (mol0.46/L0.46.s).

Efficient degradation of phenol wastewater using CuFe2O4 as highly active catalyst in the microwave-assisted catalytic wet peroxide oxidation process

Six kinds of CuFe2O4, including capsule-shaped CuFe2O4-C, plate-shaped CuFe2O4-P, polyhedral-shaped CuFe2O4-O, and irregular shaped catalysts prepared by co-precipitation (CuFe2O4-CO), by microwave heating (CuFe2O4-MW), and by hydrothermal synthesis (CuFe2O4-S), were used in the microwave-assisted catalytic wet peroxide oxidation (MW-CWPO) process to remove phenol from wastewater. The physicochemical properties of the catalysts were dependent on preparation methods. The catalytic activities were in the order of CuFe2O4-CO (95.3 %) >> CuFe2O4-P (78.8 %) > CuFe2O4-C (72.7 %) > CuFe2O4-MW (67.1 %) > CuFe2O4-S (63.3 %) > CuFe2O4-O (60.0 %). Effects of CuFe2O4-CO dosage, H2O2, pH, phenol initial concentration, anions, and MW in the MW-CWPO process were then systematically studied. Under optimal conditions of pH = 3, H2O2 = 1 mL/L, and CuFe2O4-CO = 0.5 g/L, MW energy of 99 kJ (550 W, 3 min) and 132 kJ (550 W, 4 min) were found essential to achieve 99.6 % removal rate of phenol and 95.3 % removal rate of chemical oxygen demand (COD). Possible degradation pathways were suggested: phenol was firstly oxidized into hydroquinone and catechol, which further degraded into p-benzoquinone, 1,2-benzoquinone, respectively. Finally, these compounds transformed into oxalic acid, CO2, and H2O within 4 min. The proposed mechanism suggested that the catalyst CuFe2O4-CO generates more “hot spots” due to its irregular shape, which enhances MW scattering and absorbing abilities. Consequently, the chemical composition and crystal structure of the catalyst significantly promote the decomposition of H2O2 to generate free radicals. The CuFe2O4-CO has an opportunity of potential engineering application due to its high efficiency and stability.

Determination of the amount of oxygen required for each function in the bacterial cell during phenol biodegradation in wastewater: a unique concept

The goal of this study is to provide more in-depth study into the biodegradation of phenol and to determine the amount of oxygen required for each function in the bacterial cell which is fundamental in understanding of cell metabolism and biology. The total amount of oxygen consumed by bacteria is determined using manometric technique. In the biodegradation of phenol (less than 150 mg/L) the oxygen consumed up to the plateau (the stage associated with the termination of carbon) is found to be composed of three portions, one is used to directly oxidize portion of the substrate to produce energy to allow normal cell functions to sustain life which is estimated to be 50% of the plateau BOD (biochemical oxygen demand), the second portion is to oxidize energy storage intermediate (most probably carbon mono oxide, CO, is oxidized to CO2) to release energy which is then used to power reproduction which is estimated to be 41.75% of the plateau BOD, third portion is incorporated into the produced new cells which is estimated to be 8.25% of the plateau BOD. The correlation coefficient between the initial phenol concentration and the ultimate BOD values is found to be r = 0.9999. This value of correlation coefficient, r, may indicate that microbes are, in a way, estimating the amount of food available and they grow and reproduce accordingly. This article provides a better understanding of cell metabolism and biology. This understanding of cell metabolism may offer better understanding of human cells. The results of this research paves the way for a similar research on human cells where abnormal oxygen uptake may assist in early prediction of cells dysfunction and diseases and may help in early taking the necessary precautions to avoid illness.

Quantification of phenol degradation using hydrodynamic cavitation‐based packed bed reactor based on glass balls

AbstractThe current study presents a novel and effective cavitation technique for the degradation of phenol using a hydrodynamic cavitation‐based packed bed reactor (HCPBR). Several operational parameters, including fluid velocity, hydrogen peroxide (H2O2) generation (18.06 μM of H2O2 in 60 min), and initial phenol concentration, have been studied using a HCPBR. The effective parameters for phenol degradation were found to be a fluid velocity of 85.15 m/s and an initial phenol concentration of 20 ppm. It was also noted that the presence of a glass marble‐bed (15.35%) in the cavitation reactor exhibits a substantial effect on the degradation of phenol compared to the absence of a glass marble‐bed (2.91%). The investigation also examined the effect of combining hydrodynamic cavitation with chemical oxidation processes, specifically H2O2, persulfate (Na2S2O8 and K2S2O8), and titanium dioxide, on the extent of phenol degradation. Persulfate was shown to have a significant effect on phenol degradation at 1 g/L. To clarify if free radical attack is the driving force behind degradation, the impact of radical scavengers such as n‐butanol has also been examined. Toxicological assessments revealed that, for lentil meristematic cells, the therapy was quite cytotoxic, but it needs to be improved to eliminate its genotoxic side effects. Overall, the experiment clearly demonstrated the effectiveness of the HCPBR for phenol degradation.

Synthesis of Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres for efficient aqueous phenol photocatalytic degradation

This study aims to synthesize a ternary Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres by modified Stöber technique to photodegrade aqueous phenol under UV-C light effectively. Results of the X-ray diffractogram of the as-synthesized Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres showed the nanoparticles having an average size of 126.00 nm, comparable to 150.00 nm seen in the FESEM micrograph. These sizes were supported by the EDX and FTIR results which verified the presence of Fe3O4, rGO, and SiO2, and the TEM micrograph revealed them to be spherically shaped. Also, the thermally more stable microspheres than the pure individual components and binary nanocomposites were evident in their corresponding TGA thermograms.Similarly, the photoluminescence spectra of the Fe3O4-NH2-APTES@rGO@SiO2 microspheres supported their higher photodegrading ability as a consequence of an extended e-/h+ recombination rate. The microspheres were more effective in photo-catalytically degrading the highest amount of aqueous phenol (∼89 %) than Fe3O4-NH2-APTES@rGO (∼74 %), Fe3O4-NH2-APTES@SiO2 (∼78 %), and pure Fe3O4 (∼62 %), under an optimized condition of 0.2 g/350 mL catalyst loading and 50 ppm of initial phenol concentration. The enhanced photoactivity was ascribed to the high stability and specific surface of SiO2, the synergistic influence of Fe3O4, and the rGO sheet’s rapid electron transport·H2O2 enhanced phenol degradation to 94 %.

Modeling the Kinetics, Equilibrium and Thermodynamics of Poly(acrylamide)/Sodium-Bentonite for Enhanced Phenol Removal from Aqueous Media

A composite based on polyacrylamide and Na-bentonite, designated as PAAm/Na-bentonite was prepared by in-situ radical polymerization using ammonium persulfate as an initiator and bis-acrylamide as a crosslinker. The structural and morphological features were examined by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunner − Emmet − Teller measurements. The results showed PAAm intercalation in the Na-bentonite layers. Equilibrium, thermodynamics, and kinetic studies were conducted by considering the effects of pH, initial phenol concentration, contact time and temperature. The zeta potential of the PAAm/Na-bentonite composite was calculated to understand the mechanism of phenol adsorption onto our product. The pollutant uptake behavior was determined by UV-Vis spectrophotometry. Adsorption results showed that PAAm/Na-bentonite composite showed a maximum adsorption of 160.3 mg.g−1 of 30 mg.L−1 phenol solution at pH 6 after 15 min of adsorption using 4 g.L−1 of the adsorbent. The presence of acrylamide modified the surface characteristics of the Na-bentonite and offered more adsorption sites as confirmed by XRD and SEM. Equilibrium modeling of the phenol removal process was carried out using Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) adsorption isotherms. The equilibrium adsorption data were well fitted with the Langmuir model. In addition, the kinetics of adsorption were best described by a pseudo-second-order expression rather than a first-order model. The interactions between phenol molecules and adsorbent were explained by electrostatic as well as hydrogen bonding interactions, as confirmed by the pseudo-second-order kinetic model. A model for the interactions between the composite and the phenol molecules is proposed. The negative values of Gibb’s free energy (ΔG°) confirmed that the process was spontaneous. The positive value of change in entropy (ΔS° = 0.922 JK−1mol−1) suggests that the randomness was increased at the solution/solid interface. We suggest, the results indicate that PAAm/Na-bentonite presents a significant potential as an adsorbent material for phenol removal from aqueous solutions.

Oxidative Evolution of Different Model Rosé Wines Affected by Distinct Anthocyanin and Tannin Contents

The quality of rosé wines significantly depends on their phenolic composition, particularly tannins, anthocyanins, and their derivatives, which determine the perceived color of these products and their color evolution throughout the storage and shelf-life periods. This study investigated the impact of phenolic content on the oxidation and color evolution of five different model rosé wines obtained by blending a fixed amount of grape tannins with varying concentrations of oenocyanin to modulate their respective ratio and color intensity. The solutions were monitored for color and pigment changes promoted by oxidation in a Fenton-like environment. The findings revealed a potential correlation between the initial phenolic concentration and the different degrees of oxidation within each solution, resulting in significant variations in CIELAB data. Overall, all solutions exhibited a substantial decrease in redness, with losses ranging from 23% in the darkest solution to 43% in the lightest one compared to their initial levels. Additionally, their color profiles shifted toward yellow hues, up to triple the original value, indicating the degradation of the pigments responsible for the characteristic rosé color. Greater amounts of anthocyanins preserved higher Fe(II) concentrations over time, suggesting the antioxidant role of these compounds. The whole dataset also permitted the evaluation of the different oxidation susceptibilities of individual anthocyanins, among which derived pigments, such as vitisins, proved to be notably more stable than native pigments, particularly delphinidin and petunidin.

Biochar/Delonix regia seed gum/chitosan composite as efficient adsorbent for the elimination of phenol from aqueous medium

In this study, biochar (BC) from Delonix regia pods peel and gum from Delonix regia seed (SG) were prepared, and also biochar/chitosan composite (BCS) and biochar/Delonix regia seed gum/chitosan composite (BCGS) were fabricated for the efficient adsorption of phenol. Various characterization tools such as SEM, TEM, ATR-FTIR, TGA, zeta potential, and textural investigation were studied to examine the features of the synthetized adsorbents, confirming their positive construction. It was fully studied how necessary factors, comprising pH, dose of adsorbent, contact shaking time, initial phenol concentration, and temperature influenced adsorption behavior. An obvious rise of the adsorption capacity from 60.16 to 165.20 mg/g was achieved by the modification of biochar with Delonix regia seed gum and chitosan under ideal circumstances of 2 h contact duration, pH 7, 15 °C, and a dose of 2.0 g/L. The phenol adsorption was well applied by Langmuir, Temkin, Dubinin-Radushkevich, and Sips isotherms, in addition to nonlinear pseudo-second-order kinetic model. Furthermore, the physisorption, endothermic, and spontaneous process was illustrated by thermodynamic investigation. Additionally, the fabricated adsorbents could be effectively used and regenerated without main losses of only 7.5, 4.6, and 4.0 % for BC, BCS, and BCGS, respectively in the removal percentage after seven cycles of application.

Weak magnetic field and coexisting ions accelerate phenol removal by ZVI/H2O2 system: Their efficiency and mechanism

Human activity and industrial production have led to phenol becoming a significant risk factor. The proper treatment of phenol in wastewater is essential. In this study, the utilization of weak magnetic field (WMF) and zero-valent iron (ZVI) was proposed to activate H2O2 to degrade phenol contaminant. The results show that the weak magnetic field has greatly enhanced the reaction rate of ZVI/H2O2 removal of phenol. The removal rates of phenol by ZVI/H2O2/WMF generally decreased with increasing initial pH and phenol concentrations, and firstly increase and then decrease with increasing Fe0 or H2O2 dosage. When the initial pH is 5.0, ZVI concentration of 0.2 g L−1, H2O2 concentration of 6 mM, and phenol concentration of 100 mg L−1 were used, complete removal of phenol can be achieved within 180 min at 25 °C. The degradation process was consistent with the pseudo-first-order kinetic model when the experimental data was fitted. The ZVI/H2O2/WMF process exhibited a 1.05–2.66-fold enhancement in the removal rate of phenol under various conditions, surpassing its counterpart lacking WMF. It was noticed that the presence of 1–5 mM of Ca2+, Mg2+, Cl−, SO42− ions can significantly enhance the kinetics of phenol removal by ZVI/H2O2 system with or without WMF to 2.22–10.40-fold, but NO3−, CO32−, PO43− inhibited the reaction significantly in the following order: PO43− > CO32− > NO3−. Moreover, pre-magnetization for 3 min could enhance the ZVI/H2O2 process which was valuable in treatment of real wastewater. The hydroxyl radical has been identified as the primary radical species responsible for phenol degradation. The presence of WMF accelerates the corrosion rate of ZVI, thereby promoting the release of Fe2+ ions, which in turn induces an increased production of hydroxyl radicals and facilitates phenol degradation. The compounds hydroquinone, benzoquinone, catechol, maleic acid, and CO2 were identified using GC-MS, and degradation pathways were proposed. Employing WMF in combination with various ions like Ca2+, Mg2+, Cl−, SO42− is a novel method, which can enhance oxidation capacity of ZVI/H2O2 and may lead to economic benefit.

Fast and efficient extraction of phenol from aqueous phase using deep eutectic solvents: Experimental and density functional theory investigation for interactions studies

Phenol is carcinogenic and toxic to human beings and therefore it is necessary to remove this toxic pollutant from water. Hydrophobic deep eutectic solvents (DESs) were prepared using trioctylamine (TOA) as hydrogen bond acceptor (HBA) and 2-hydroxybenzoic acid and 4-dodecylbenzenesulfonic acid as hydrogen bond donors (HBDs) for extraction of phenol from aqueous media. Fourier transformer infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) were performed for functional group and thermal stability determination, respectively. Phenol extraction efficiency of DESs was studied under different experimental parameters, such as initial pH of phenol solution (2–10), contact time (1–15 min), mixing ratio of volume of DESs to aqueous media (VDES:Vaq.) (1:10–1:50 mL), initial concentration of phenol (1000–5000 ppm) and temperature (25 °C–55 °C). More than 97 % extraction efficiency of DES for phenol was achieved using contact time of 5 min, initial phenol concentration of 2500 ppm, VDES:Vaq in a ratio of 1:10 mL, and temperature of 25 °C. The values of ΔG° calculated for phenol extraction at various temperatures have negative values, confirming that the phenol movement from water phase to DESs phase is spontaneous in nature. Density functional theory (DFT) simulations were conducted to study the interaction of DESs with water and phenol. In addition, DFT was used to determine the interaction energy of DESs with water and phenol. The considerably higher interaction energies (−20.4 and 18.2 kcal/mol) obtained with both DESs for phenol over water emphasize the selective separation efficiency of DESs for phenol. The experimental results confirmed that these synthesised DESs can effectively extract phenol from the aqueous phase to the organic phase.

An effective strategy for biodegradation of high concentration phenol in soil via biochar-immobilized Rhodococcus pyridinivorans B403.

High concentration of phenol residues in soil are harmful to human health and ecological safety. However, limited information is available on the in-situ bioremediation of phenol-contaminated soil using biochar as a carrier for bacteria. In this study, bamboo -derived biochar was screened as a carrier to assemble microorganism-immobilized composite with Rhodococcus pyridinivorans B403. Then, SEM used to observe the micromorphology of composite and its bioactivity was detected in solution and soil. Finally, we investigated the effects of free B403 and biochar-immobilized B403 (BCJ) on phenol biodegradation in two types of soils and different initial phenol concentrations. Findings showed that bacterial cells were intensively distributed in/onto the carriers, showing high survival. Immobilisation increased the phenol degradation rate of strain B403 by 1.45 times (37.7mg/(L·h)). The phenol removed by BCJ in soil was 81% higher than free B403 on the first day. Moreover, the removal of BCJ remained above 51% even at phenol concentration of 1,500mg/kg, while it was only 15% for free B403. Compared with the other treatment groups, BCJ showed the best phenol removal effect in both tested soils. Our results indicate that the biochar-B403 composite has great potential in the remediation of high phenol-contaminated soil.

Using red mud to prepare the iron-bearing catalyst for the efficient degradation of phenol in the Fenton-like process

Phenol pollution is widely environmental and health problems that require new insights and urgent attention. A iron-bearing catalyst (FRM/2%A) was prepared with red mud by HCl dissolution, ascorbic acid reducing and precipitation of filter liquor, and activated H2O2 to degrade the phenol in synthetic wastewater. Results show that FRM/2%A had the highest degradation efficiency (99.3 %) in the reaction time of 5 min among investigative samples, due to the production of ferrous polymetallic oxides on the catalyst and the formation of mesoscopic particles and microcellular structures. The optimal conditions were 1 g/L of catalyst dosage, 5 mM of H2O2 concentration, 3–6 of initial pH and 100 mg/L of initial concentration of phenol in the FRM/2%A/H2O2 system. The degradation data fit into the pseudo-first-order kinetics model and the reaction rate constant (k) of FRM/2%A was 0.865 min−1. The removal efficiency (77 %) of COD below the value (99.3 %) of phenol degradation implied the intermediates generating during the phenol degradation. The possible degradation pathway was proposed as phenol → catechol → benzoquinone → muconic acid → small molecular organic acids → CO2 and H2O. The findings suggested a new way for the synthesis of the efficient catalyst with RM and optimal operating strategies for the treatment of phenol wastewater.

Hypercrosslinked Hydrogel Composite Membranes Targeted for Removal of Volatile Organic Compounds via Selective Solution-Diffusion in Membrane Distillation.

Membrane distillation (MD) has attracted considerable interest in hypersaline wastewater treatment. However, its practicability is severely impeded by the ineffective interception of volatile organic compounds (VOCs), which seriously affects the product water quality. Herein, a hypercrosslinked alginate (Alg)/aluminum (Al) hydrogel composite membrane is facilely fabricated via Alg pregel formation and ionic crosslinking for efficient VOC interception. The obtained MD membrane shows a sufficient phenol rejection of 99.52% at the phenol concentration of 100 ppm, which is the highest rejection among the reported MD membranes. Moreover, the hydrogel composite membrane maintains a high phenol interception (>99%), regardless of the feed temperature, initial phenol concentration, and operating time. Diffusion experiments and molecular dynamics simulation verify that the selective diffusion is the dominant mechanism for VOCs-water separation. Phenol experiences a higher energy barrier to pass through the dense hydrogel layer compared to water molecules as the stronger interaction between phenol-Alg compared with water-Alg. Benefited from the dense and hydratable Alg/Al hydrogel layer, the composite membrane also exhibits robust resistance to wetting and fouling during long-term operation. The superior VOCs removal efficiency and excellent durability endow the hydrogel composite membrane with a promising application for treating complex wastewater containing both volatile and nonvolatile contaminants.

Preparation of Mn-doped sludge biochar and its catalytic activity to persulfate for phenol removal.

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 100mg/L phenol within 180min, 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.

Removal of phenol from wastewater using Luffa cylindrica fibers in a packed bed column: Optimization, isotherm and kinetic studies

This research entails a comparison of the effectiveness of unmodified Luffa cylindrica fiber in a fully packed bed (RLCF) and NaOH-modified Luffa cylindrica fiber in another fully packed bed (MLCF) in the context of phenol removal from wastewater. Experimental data obtained through batch adsorption experiments were utilized to determine the most suitable model. It was observed that as the initial concentration of phenol increased from 100 to 500 mg/l, the maximum percentage removal increased from 63.5 to 83.1% for RLCF-PB and from 89.9 to 99.5% for MLCF-PB. The correlation coefficient (R2) was calculated for the Langmuir, Freundlich, Temkin, Harkin-Jura, Halsey, and Flory-Huggins models for both materials. The analysis revealed that the pseudo-second-order model was the most suitable, followed by the Elovich model, with the pseudo-first-order model being the least suitable. The Weber-Morris diffusion model suggested that pore diffusion was the rate-determining step, and diffusion at the border layer was determined to be endothermic, feasible, heterogeneous, and spontaneous. In summary, this study indicates that MLCF-PB is a promising material for the efficient removal of phenol from aqueous solutions.

Degradation of phenol in wastewater through an integrated dielectric barrier discharge and Fenton/photo-Fenton process

In this study, a non-thermal dielectric barrier discharge-Fenton/photo-Fenton process was investigated to remove phenol from synthetic wastewater. The changes and optimal values of influencing parameters, including treatment time, iron concentration, phenol initial concentration, and pH, were investigated based on the central composite design (CCD) method. The presence of 0.4 mmol/L of iron in the phenol solution with a concentration of 100 mg/L increased the removal efficiency and pseudo-first-order kinetic constant compared to dielectric barrier discharge cold plasma (DBDP) alone from 0.0824 min−1 and 56.8% to 0.2078 min−1 and 86.83%, respectively. The phenol removal efficiency was reduced to 52.9%, 45.6% and 31.8% by adding tert-butyl alcohol (TBA) with concentrations of 50, 100, and 200 mg/l, respectively. After 12 min of DBDP irradiation, the pH of the sample decreased from 5.95 to 3.42, and the temperature of the sample increased from 19.3 to 37.2 degrees Celsius. The chemical oxygen demand (COD) of the sample containing 100 mg/L phenol under plasma-Fenton/photo-Fenton irradiation decreased from 241 mg/L to 161 mg/L. Phenol removal efficiency after 10 min of treatment in the presence of 0.4 mmol/L of iron with the reactor volume of 50 mL was 87%, but the efficiency decreased to 76%, 47%, and 9% by increasing the volume to 100, 200, and 400 mL, respectively. Reducing the power led to a decrease in the removal efficiency from 56.8% for 100 W power to 10.8% for 40 W. The energy efficiency for 50% removal by DBDP and plasma-Fenton/photo-Fenton systems was 5.86×10−3 kWh/mg and 1.27×10−3 kWh/mg, respectively.

Analysis of Photocatalytic Degradation of Phenol by Zinc Oxide Using Response Surface Methodology.

In this study, the photocatalytic degradation of phenol, which is commonly found in industrial wastewater at high rates, was investigated using a zinc oxide (ZnO) catalyst. It is thought that our findings will contribute to the removal of phenol in industrial wastewater. The experimental study was conducted in a batch-type air-fed cylindrical photocatalytic reactor, and a central composite design (CCD) was chosen and analyzed using response surface methodology (RSM). The study aimed to explore the effects of initial phenol concentration, catalyst concentration, airflow rate, and degradation time on the photocatalytic degradation of phenol and the removal efficiency of total organic carbon (TOC). A quadratic regression model was developed to establish the relationship between phenol degradation, TOC removal effectiveness, and the four factors mentioned. The validity of the model was assessed through an analysis of variance (ANOVA). A good agreement was observed between the model results and the experimental data. As a result of the experiments carried out under optimized conditions, the degradation percentage of phenol was found to be 77.15 %, and the degradation percentage of TOC was 59.87 %. Additionally, pseudo-first-order kinetics were used in the photocatalytic degradation of phenol.

Inhibition of phenol entering condensed freshwater by activated peroxides during photothermal distillation desalination process

The formation of “high-temperature, high-salt and intense-light” environment during the new process of photothermal distillation desalination causes volatile pollutants such as phenol in seawater to volatilize into condensed freshwater, resulting the quality safety risk of the freshwater. In this work, activated peroxides processes including hydrogen peroxide (H2O2), peroxyacetic acid (PAA), peroxodisulfate (PDS) and peroxymonosulfate (PMS) were applied for the inhibition of phenol entering condensed freshwater by making full use of the “high-temperature, high-salt, intense-light” media. Under the same conditions, the phenol removal efficiency by the activated peroxides were in the order of H2O2 < PDS < PAA < PMS. The effects of the salinity, peroxide dosage, initial phenol concentration, humic acid and sunlight intensity on the distillation rates (RD) of phenol were investigated. It was revealed that the main factor for activation of H2O2, PAA, PDS and PMS were heat, Cl−/heat, heat/light and Cl−, respectively. Though both PMS and PAA could completely degrade phenol and reduced its entry into condensed freshwater, PMS formed fewer halogenated distillation by-products and was more promising for future applications.