Phenol Removal Research Articles

Potential bioremediation of lead and phenol by sunflower seed husk and rice straw-based biochar hybridized with bacterial consortium: a kinetic study

Environmental pollution is a global phenomenon and troublesome fact that poses a grave risk to all living entities. Via coupling carbonaceous feedstocks with outstanding microbial activity, kinetic experiments were established using the consortium of Proteus mirabilis and Raoultella planticola, biochar-derived sunflower seed husk (SHB) and rice straw (RSB), and their composites, which investigated at 30 °C (150 rpm) to eliminate 700 mg L−1 lead (120 h) and phenol (168 h) from synthetic wastewater. The derived biochars physicochemical properties of were studied. According to adsorption capacity (qe), consortium-SHB composites and consortium-RSB composites removed lead completely (70 mg g−1) within 48 h and 66 h, respectively. Besides, phenol was remediated entirely after 42 h and 48 h by both composite systems (69.90 mg g−1), respectively, comparing with bacterial consortium only or parent SHB and RSB. Moreover, four kinetic models were studied to describe the bioremediation process. Fractional power and Elovich models could be recommended for describing the adsorption kinetics for lead and phenol removal by the studied biomaterials with high correlation coefficient (R2 ≥ 0.91 for Pb2+ and ≥ 0.93 for phenol) and lower residual root mean square error (RMSE) and chi-square (X2). Overall, bacterial consortium-biochar composites exhibited greater remediation of lead and phenol than the sum of each single bacterial consortium and biochar systems; reflecting synergistic interaction of adsorptive capability of biochar and metabolic performance of bacterial consortium, as denoted by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The current study addressed the successful design of employing functional remediating consortium immobilized on waste biomass-derived biochar as a conducive alternative eco-sorbent and economic platform to detoxify organic and inorganic pollutants.

Sustainable waste utilization: Geopolymeric fly ash waste as an effective phenol adsorbent for environmental remediation

Rapid industrialization and urbanization generate significant waste, including fly ash, posing environmental challenges. Utilizing these materials is essential to mitigate impacts and promote sustainable development. This research paper focuses on the innovative application of geopolymeric fly ash (GEOFA) waste modified with titanium oxide (TiO2) (GEOFA-TiO2) as a promising adsorbent for the removal of phenol compounds from contaminated water. Analysis showed that the modification process resulted in the formation of functional groups such as -OH, which aided in the adsorption process. Adsorption studies were conducted to evaluate the influence of pH, temperature, and concentration on phenol removal. The maximum percentage removal of phenol was achieved at optimum conditions of pH 6 and a temperature of 25 °C, with an adsorption capacity of 166.7 mg/g. The adsorption process followed the Langmuir model, suggesting a monolayer adsorption mechanism and the thermodynamic studies revealed that the phenol adsorption onto GEOFA-TiO2 was an endothermic process with a promising affinity between phenol and the adsorbent. This study demonstrates the effective use of modified fly ash-based adsorbents to remove phenolic contaminants. By repurposing waste materials, this research addresses waste management challenges and promotes sustainable practices, reveling their potential for environmental remediation.

Immobilized bioreactor for enhanced ammonia, phosphorus, and phenol removal and effects of phenol on microbial communities, potential functions, and nitrogen metabolism

In the present study, an immobilized bioreactor was established to remove ammonia (NH4+-N), phosphate (PO43--P), and phenol using composite mycelium spheres (CMP) as the immobilization material in combination with Pseudomonas sp. Y1. Under optimal operating conditions, the bioreactor achieved 98.07, 91.71, and 92.57 % removal of NH4+-N, PO43--P, and phenol, respectively. The results showed that the bioreactor removed PO43--P by biomineralization and co-precipitation. Phenol removal relied on a Fenton-like reaction achieved by CMP-induced quinone redox cycling. High-throughput sequencing analysis and functional gene prediction indicated that Pseudomonas was the dominant genus and that the bioreactor had much potential for nitrogen removal, respectively. In addition, phenol affected the performance of functional genes and the associated enzymes, which influenced the nitrogen metabolism process in the bioreactor. This work serves as a guideline for the development of more stable and sustainable composite pollution removal technologies and fungal-bacterial symbiotic systems.

Performance improvement of metagenomic laccase immobilized on nanocellulose-reinforced hydrogel nanocomposites for enhanced delignification and detoxification

Immobilization enhances the potential of laccases to degrade lignocellulosic waste, thereby providing an efficient approach for delignification and detoxification. In this study, a comparative analysis of the activity of free and immobilized metagenome-derived laccase (PersiLac2) on nanocellulose (NC)-reinforced hydrogel nanocomposites was performed, and the effectiveness of immobilized laccase in delignification, particularly in relation to rice straw degradation and phenol production, was evaluated. After 1 h of incubation at 90 °C, the immobilized laccase retained 80% of its activity, exhibiting 1.6-fold higher retention than that of the free enzyme. At alkaline pH (8.0–9.0) the free enzyme demonstrated enzymatic activity of 55–65%, while this value was 59–73% for the immobilized form. Immobilization also facilitated easy recovery and reuse of PersiLac2. After 15 cycles, 76.64% of enzyme activity was preserved, highlighting the improved reusability and stability of the immobilized enzyme. Furthermore, leaching tests revealed that the hydrogel-enzyme conjugate maintained a strong connection, with only approximately 20% of the enzyme being leached after 240 min of incubation at 60 °C. This indicates a strong connection between the hydrogel and enzyme structure. Additionally, our study also employed SEM and FTIR analyses, demonstrating the superior performance of immobilized PersiLac2 compared to its free form in the treatment of rice straw. Furthermore, the immobilized enzyme reduced soluble phenols (77.45%) in the slurry of acid-pretreated rice straw. Overall, our findings highlight the potential of immobilizing PersiLac2 on hydrogel nanocomposites to improve enzyme stability, activity, and reusability. This study demonstrates a promising pathway for efficient delignification, phenolic compound removal, and enhanced biomass processing and waste management.

A novel photo-enzyme coupling catalysis system with electronic channels for the degradation of bisphenol a in water

How to enhance the efficiency of electron transfer between the photocatalytic system and the enzymatic catalytic system is the key to constructing novel and efficient photo-enzyme coupling system. Hence, polypyrrole (Ppy) with high adsorbability was employed as a bridge to establish an electron transfer pathway between the photocatalytic system and the enzymatic catalytic system in this work, enhancing both the immobilized amount of the biocatalyst and the efficiency of electron transfer and catalytic activity in the photo-enzyme coupling system. After immobilization optimization, the unit loading of horseradish peroxidase (HRP) can reach 831.00 mg/g, and the immobilized HRP has strong pH stability, storage stability and cycling stability. Moreover, the conversion efficiency (Kcat/Km) of immobilized HRP was 0.4800 min−1 mM−1, higher than that of free HRP (0.1560 min−1 mM−1). Moreover, the successful construction of the photo-enzyme coupling system was confirmed by a series of physical characterization, such as FT-IR, XRD, TGA and XPS. In the degradation experiment of bisphenol A (BPA), the degradation rate of BPA by HRP/Ppy/CN photo-enzyme coupling system can reach 86.03 % within 60 min and rate constant is 0.0329 min−1, which is 1.91 times and 3.19 times that of pure g-C3N4, respectively. This work provides a new idea for the development of an efficient photo-enzyme coupled catalytic system and the effective removal of phenols in water.

Phenol removal from aqueous solution using advanced oxidation process enabled by a hybrid system: UV/H2O2/O3/TiO2

The need for healthy and pollution-free water is vital given the world’s industrialization and population explosion. The removal of chemical pollutants, especially phenol and phenolic compounds, from urban and industrial wastewaters is of particular importance due to their high water solubility and toxicity. Previous physicochemical techniques for phenol removal are no longer cost-effective. Advanced oxidation processes (AOPs) using various oxidizing agents have been recently recognized as an effective method for removing organic compounds through mineralization. The present work evaluated the phenol (100 ppm) removal from aqueous solutions through photooxidation systems of UV exposure, UV/TiO2, O3, O3/TiO2, H2O2, H2O2/UV, H2O2/TiO2, H2O2/TiO2/O3 and H2O2/TiO2/O3/UV. The results showed a decrease in the phenol concentration by almost half using UV, UV/TiO2, O3, O3/TiO2, H2O2, H2O2/UV and H2O2/TiO2 within 50 min. The phenol concentration reached 50 and 71 ppm using H2O2/TiO2/O3 system within 50 and 70 min, respectively. The UV/H2O2/O3/TiO2 system reduced the phenol concentration to zero after 40 min. The findings revealed that the AOP enabled by the UV/H2O2/O3/TiO2 combined system caused the complete removal of phenol, highlighting the capacity of the proposed system to remove toxic aromatic compounds such as phenol released during the wastewater treatment process.

Simultaneous removal of phenol and Cu(II) from wastewater by tallow dihydroxyethyl betaine modified bentonite

Simultaneous removal of phenol and Cu(II) from wastewater by tallow dihydroxyethyl betaine modified bentonite

Ca/Al and Mg/Al LDH Supported on Biochars As Effective Adsorbent and Highly Regeneration Ability for Phenol Removal from Aqueous Solution

This research conducted a composite of Ca/Al and Mg/Al Layered double hydroxide with Biochar material using co-precipitation method. Characterization results were carried out with various analyses including XRD, FT-IR, and BET. The results of XRD analysis on Ca/Al-BC showed peaks at 10-11° and 22°, while the Mg/Al-BC material showed peaks at 11. 41° (003), 22. 95° (002), 34. 05° (012) and 60.2° (116). The FT-IR analysis showed that Ca/Al and Mg/Al LDH materials composited with Biochar have functional groups of -OH, nitrate ions, C=O, C-H, C-O, and M-O. BET analysis results show an increase in surface area in Ca/Al and Mg/Al LDH materials after composite with biochar from 29.333 m2/g to 158.291 m2/g in Mg/Al-BC, while in Mg/Al-BC there is an increase from 23.150 m2/g to 111.404 m2/g. The Ca/Al-BC and Mg/Al-BC composite materials have better stability than Ca/Al and Mg/Al LDH materials that can be used up to the fifth cycle. Hydrogen bonding and π-π interaction between the adsorbent and the aromatic ring on phenol can affect the adsorption process.

Integrated Process for High Phenol Removal from Wastewater Employing a ZnO Nanocatalyst in an Ozonation Reaction in a Packed Bubble Column Reactor

The use of an ozonized bubble column reactor (OBCR) in wastewater treatment is advantageous due to its efficient mixing and mass transfer characteristics. Among all high-performance features, the ozonation reaction in a BCR undergoes a low dissolution of O3 in the reactor with a limited reaction rate. In this study, the ozonation reaction of phenol in an OBCR was tested using a ZnO nanocatalyst and alumina balls as packing material. Three concentrations of O3 were evaluated (i.e., 10, 15, and 20 ppm), and 20 ppm was found to be the optimum concentration for phenol degradation. Also, two doses (i.e., 0.05 and 0.1 g/L) of ZnO nanocatalysts were applied in the reaction mixture, with the optimal dose found to be 0.1 g/L. Accordingly, three phenol concentrations were investigated in the OBCR (i.e., 15, 20, and 25 ppm) using four treatment methods (i.e., O3 alone, O3/Al2O3, O3/ZnO nanocatalyst, and O3/Al2O3/ZnO nanocatalyst). At a contact time of 60 min and phenol concentration of 15 ppm, the removal rate was 66.2, 73.1, 74.5, and 86.8% for each treatment method, respectively. The treatment experiment that applied the O3/Al2O3/ZnO nanocatalyst produced the highest phenol conversion into CO2 and H2O in the shortest contact time for all phenol concentrations. Thus, the OBCR employed with a ZnO nanocatalyst plus packing material is a promising technology for the rapid and active removal of phenol because it enhances the number of hydroxyl radicals (•OH) generated, which ultimately increases the oxidation activity in the OBCR. Also, the results showed efficient flow characteristics in the OBCR, with channeling problems averted due to appropriate gas movement resulting from the use of packing materials. Finally, it was found that the ozonation process in an OBCR is an efficient method for phenol conversion with good economic feasibility.

Water hyacinth derived hierarchical porous biochar absorbent: Ideal peroxydisulfate activator for efficient phenol degradation via an electron-transfer pathway

In this paper, a facile hydrothermal pretreatment and molten salt activation route was presented for preparing a self-doped porous biochar (HMBC) from a nitrogenous biomass precursor of water hyacinth. With an ultrahigh specific surface area (2240 m2 g−1), well-developed hierarchical porous structure, created internal structural defects and doped surface functionalities, HMBC exhibited an excellent adsorption performance and catalytic activity for phenol removal via peroxydisulfate (PDS) activation. Specifically, the porous structure promoted the adsorption of PDS on HMBC, forming a highly active HMBC/PDS* complex and thereby increasing the oxidation potential of the system. Meanwhile, the carbon defective structure, graphitic N and CO groups enhanced the electron transfer process, favoring the HMBC/PDS system to catalyze phenol oxidation via an electron transfer dominated pathway. Thus, the system degraded phenol effectively with an ultralow activation energy of 4.9 kJ mol−1 and a remarkable oxidant utilization efficiency of 8.2 mol mol-oxidant−1 h−1 g−1. More importantly, the system exhibited excellent resistance to water quality and good adaptability for decontaminating different organic pollutants with satisfactory mineralization efficiency. This study offers valuable insights into the rational designing of a low-cost biochar catalyst for efficient PDS activation towards organic wastewater remediation.

Adsorption synergy electrocatalytic degradation of phenol by active oxygen-containing species generated in Co-coal based cathode and graphite anode

Abstract The coal base electrodes and efficient coal base loaded cobalt electrodes (Co-CE) were prepared by pyrolysis method of low rank coal united activation method of KOH in order to develop more pores structures. The morphology of electrodes were characterized by Scanning electron microscopy, meanwhile, the type of elements were detected by energy dispersive spectroscopy (EDS). The electrochemical performance of electrodes were tested by cyclic voltammetry and electrochemical impedance spectroscopy. The lamella structures and pores were observed in microtopography of electrodes and the cobalt were successfully loaded in Co-CE from the EDS analysis. The operating conditions of processing time, current density, electrolyte concentration, pH and initial phenol concentration on this electrochemical system in single factor experiment were separately explored, correspondingly, the value was 180 min, 40 mA·cm−2, 0.01 mol·L−1, 2, 100 mg·L−1, and the phenol removal rate (R) were at the range of 47.64–67.84%. In the optimization experiment of JMP design, the removal rate could reach at 83.47%. The response surface methodology was employed for optimizing operation conditions to improve R. And the prediction model obtained for the response can be represented as: R = 66.5275 + 6.7311X 1 – 5.4197X 4 – 5.2303X 5 + 4.9555X 1 2 – 12.5219X 2 2 – 6.2912X 4 2 + 16.0937X 5 2 + 2.4109X 2 X 4 – 7.910X 3 X 4 – 3.0123X 3 X 5 – 2.183X 4 X 5. The optimized conditions were pH 3, 100 mg·L−1 of phenol concentration, 0.1 mol/L of electrolyte concentration, 35 mA/cm2 of current density, and 180 min of processing time. Meanwhile, the predicted R was 90.86%, the actual R of three parallel experiments were 91.2%, 89.3%, 91.05%, which were well consistent with the predicted value. Additionally, the degradation mechanism was proposed as that the adsorption in pore structures synergy electrocatalytic effect of Co-CE. Micro-electric fields formed in pores and the transition metal catalysis accelerated the transformation of cathode hydrogen peroxide to generate hydroxyl radical (·OH). Furthermore, the ·OH were produced both by cathode and anode which promoted the degradation of phenol. This high catalytic activity and low cost Co-CE is a kind of prospective electrode for electrochemical degradation of phenolic wastewater.

Bio-synthesized ZnO nanoparticles and sunlight-driven photocatalysis for environmentally-friendly and sustainable route of synthetic petroleum refinery wastewater treatment

The design of a green photocatalytic system that harnesses renewable and eco-friendly constituents holds the potential to offer valuable insights into alternative strategies for treating toxic multi-components in refinery water effluents. A significant challenge in implementing a practical and viable approach is the utilization of solar energy—an abundant, natural, and cost-effective resource—for photochemical processes within advanced oxidation processes. In this study, we explored the use of zinc oxide nanoparticles (ZnO NPs) as photocatalyst prepared via an environmentally friendly synthesis approach, resulting in the formation of crystalline wurtzite nanoparticles, with an average size of about 14 nm relatively spherical in shape. Notably, the extract derived from Moringa oleifera was employed in this investigation. These nanoparticles were characterized and validated using various characterization techniques, including X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. For comparison, conventionally synthesized ZnO NPs were also included in the evaluations. The findings reveal that, under illumination, biosynthesized ZnO nanoparticles (NPs) exhibit photocatalytic performance in effectively breaking down the organic compounds present in synthetic petroleum wastewater. Photochemical analysis further illustrates the degradation efficiency of Green-ZnO, which, within 180 min of irradiation resulted in 51%, 52%, 88%, and 93% of removal for Phenol, O-Cresol. Under optimal loading conditions, NPs produced via the green synthesis approach perform better when compared to chemically synthesized ZnO. This significant improvement in photocatalytic activity underscores the potential of eco-friendly synthesis methods in achieving enhanced water treatment efficiency.

Surface functionalization of magnetite nanoparticles for remediation enhancement of phenol from aqueous solutions

Phenol is a toxic pollutant generated by industries. It can diminish the supply of clean water and is hazardous to human health. Hence, an effective abatement method is important to remove phenol from water sources. The following amine-functionalized magnetite nanoparticles, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and polyethylenehexamine (PEHA), were used to study the adsorption performances of phenol from the prepared samples. The morphological study revealed long rod shapes with rough and sharp edges, while the elemental analysis presented the addition of two elements, C and N atoms. In addition, the TETA@MNP possessed weaker magnetism compared to MNPs, showing that the surface functionalization of MNPs was successful. TETA@MNP showed the highest percentage for phenol removal compared to others. The TETA@MNP achieved a removal efficiency of 99.2% at optimum conditions of 60 mg dosage, contact time of 25 min, and pH of 7. TETA@MNP obeyed the pseudo-second-order kinetic model and the Freundlich isotherm model, with coefficients of determination (R2) of 0.9765 and 0.9682, respectively. The reusability study has demonstrated that TETA@MNP can be reused approximately 6 times with extremely minor loss. Therefore, TETA@MNP is a good adsorbent for the adsorption of phenol from prepared sample solutions.

Improvement of the activity of a new nano magnetic titanium catalyst by using alkaline for refinery wastewater oxidation treatment in a batch baffled reactor

In order to reach pure water, it is essential to develop new technology for eliminating phenol from the wastewater. In this work, a nano-composite catalyst (5 % Fe2O3 + 10 % alkaline/TiO2) has been prepared and its performance to enhance the activity of catalytic wet peroxide oxidation (CWPO) process for removal of phenol has been examined. The new nano-composite catalyst is tested by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Energy dispersive X-ray (EDX) and scanning-electron-microscopy (SEM). A baffled batch reactor is used to evaluate the activity of new nano-composite catalyst at various temperatures (30–80 °C) and reaction times (30–90 min), utilizing hydrogen peroxide (H2O2) as oxidizing agent. The new design of digital baffled batch reactor prevents the fuel swirling, thus improving agitation. The experimental data of the CWPO technology prove that the best phenol removal (95.931 %) was carried out at 80 °C, the reaction time of 90 min, and in the presence of nano-composite catalyst ((5 % Fe2O3 + 10 % alkaline)/TiO2). Modeling investigation for the CWPO is examined in order to estimate the better process kinetic. The simulation technique explains dramatic agreement in comparing with the experimental data (error < 5 %). The optimal CWPO conditions in order to achieve pure water (phenol removal >99 %) are at reaction time of 198 min, process temperature of 85 °C, and initial phenol concentration of 1000 ppm.

Hybrid electromagnetic field-flow by electrode configuration for the removal of phenol from contaminated water

In this study, we introduce an electrode configuration setup to study the effect of an electromagnetic field (EMF) and electric potential (EP) on phenol removal in a continuous adsorption process. Feed water contaminated with dissolved phenol was exposed to EMF and passed through charged activated carbon electrodes prepared from Phoenix dactylifera (palm tree) biowaste. This study investigated the effects of magnetic field exposure, electric potential, feed salinity, and electrode substrate type. The results revealed that the highest adsorption uptake capacity of 47.2 mg/g was achieved using an aluminum substrate (AS) with EMF at zero salinity. The phenol adsorption kinetics followed a pseudo-second-order adsorption rate and diffusion model, indicating that intraparticle diffusion was the primary rate-limiting mechanism. The increased phenol adsorption uptake capacity brought on by the EMF may result from the improved mass transfer and mobility of the adsorbate and, consequently, the increased effectiveness of the internal diffusion of the pollutants. Finally, a regeneration efficiency of 99 % was achieved using NaOH at a salinity of 5,000 ppm.

Steam gasification of char derived from refuse-derived fuel pyrolysis: adsorption behaviour in phenol solutions

ABSTRACT The increasing waste generation trends resulted in growing attention to the technologies that aim to reduce or prevent landfilling. The pyrolysis and gasification of refuse-derived fuel (RDF) allow waste to be turned into new raw materials, like pyrolysis gas and syngas. However, the wet gas cleaning processes result in the production of highly contaminated liquid waste. Phenolic compounds are common constituents of this wastewater and often appear in the wastewater of other industries as well. In this research, the laboratory-scale steam gasification of an RDF char was performed to produce syngas and adsorbent simultaneously. The RDF was previously pyrolyzed at 700 °C maximum temperature in a Hungarian pyrolysis pilot plant with approximately 120 kg h−1 capacity. In this thermal waste processing plant, the pyrolysis gas is already utilised by burning, but currently, the char ends up in landfills. The gasification of char samples was examined with different steam-to-carbon ratios (0.56, 0.84, and 1.12) and duration (30, 60, and 120 min) at 900 °C. Following gasification, the phenol removal capability of the solid by-products was investigated. The results show that its composition and energetic properties make the produced syngas more suitable to use as a raw material in the chemical industry rather than a fuel. At lower concentrations, the effectiveness of the solid by-product for phenol removal was comparable to commercial activated carbon. These are promising results about producing activated carbon from waste without any chemical treatment.

Performance and mechanism of enhanced phenolic compounds treatment via mycelial pellets

AbstractBACKGROUNDBiological enhancement in organic wastewater treatment is currently considered an effective and economical method. As a biomass carrier, mycelial pellets are attracting increasing attention, with substantial progress recently being made. To investigate their bioaugmentation effect as a biomass carrier, mycelial pellets with immobilized phenol‐degrading bacteria were applied in a sequencing batch reactor. The phenolic compound removal efficiency of the mycelial pellet‐enhanced system was then studied and compared to the control aerobic activated sludge‐enhanced system. Finally, the settling velocity, internal structure, and surface properties were studied to explore the main bioaugmentation mechanisms of the mycelial pellets.RESULTSThe stable degradation effects of phenolic compounds and total organic carbon (TOC) were observed in both systems. In the mycelial pellet system, the biological removal efficiency was approximately 0.5 mg phenolic compounds L−1 d−1MLSS−1 and 0.4 mg TOC L−1 d−1MLSS−1, which was higher than the aerobic activated sludge system. Bioaugmentation by the pellets was mainly attributed to the structure of the connected macropores, the electrostatic attraction of positive charges, the adsorption of functional groups on the hypha surface, and flocculation due to the extracellular polymeric substances secreted on the pellet.CONCLUSIONThe excellent phenolic compound removal efficiency and bioaugmentation effect of the mycelial pellets suggest their potential to enhance organic wastewater treatment as a biomass carrier. © 2023 Society of Chemical Industry.

Enhancing rubber (Hevea brasiliensis) seed shell biochar through acid-base modification for effective phenol removal from aqueous environments

This work encompasses using acid-base modified rubber seed shell biochar (RSSB) as an adsorption approach to eradicate phenol from aqueous mediums. Potassium hydroxide (KOH) was used pre-pyrolysis to modify the RSS, and hydrochloric acid (HCl) was used post-pyrolysis to modify the RSSB. The methodology was divided into three stages: RSS pretreatment, RSS base-modification and pyrolysis, and RSSB acid-modification and processing. Temperature, pH and several other factors were investigated for their impacts on the adsorbent, and optimal conditions were established at pH 6, 1.0 g of rubber seed shell biochar (RSSB), 50 mg/L initial concentration, 120 min contact time, and 30 °C temperature. The highest phenol removal efficiency was recorded at 97.21 % using the RSSB-700 adsorbent. Thermodynamic, kinetic and isotherm studies were carried out on the adsorbents using the non-linear modelling approach. The pseudo-second-order kinetic model was declared optimal because the adsorption rate closely followed it, with minimal difference between the experimental and computed values. The maximum RSSB adsorption capacity is 13.32 mg/g, according to the equilibrium results, which follow the Langmuir isotherm equation. Thus, the aim of this research and all documented objectives have been fulfilled.

Biochar enhances microbial degradation of phenol in water: Response surface optimization

The utilization of biochar-immobilized microorganisms is an effective method for eliminating phenol from water. However, the main challenge to the practical implementation of this method is the high susceptibility of bacteria to environmental factors. In this study, biochar was used to reduce microbial susceptibility to high concentrations of phenol. Demineralized biochar obtained at high temperatures (600/800/1000 °C) was used to immobilize phenol-degrading bacteria (PDB) and enhance phenol removal. Biodegradation was inhibited by high concentrations of phenol (>1300 mg/L). In contrast, when microorganisms were combined with biochar, up to 82.4% phenol removal occurred, surpassing the efficacy of phenol degradation by a single microorganism (42%). Characterization techniques such as SEM, XRD, and XPS were used to analyze the properties and immobilization effect of biochar. The addition of biochar altered the dominant species of PDB to include Serratia, Ralstonia and Enterobacter. Response surface analysis indicated that both biochar pyrolysis temperature and experimental temperature significantly influenced the phenol removal rate. Thus, this paper provides methodological guidance for the application of biochar-immobilized microorganisms for phenol wastewater treatment.

Applying bottom ash as an alternative Fenton catalyst for effective removal of phenol from aqueous environment.

In this study, coal bottom ash from a thermoelectric plant was tested as an alternative Fenton catalyst for phenol degradation in water. The effect of operating parameters such as initial pH, catalyst dosage and H2O2 concentration were evaluated. The characterization results indicated that the material has a mesoporous structure, with active species (Fe) well distributed on its surface. Under the optimal reaction conditions (6mM H2O2, 1g L-1 of catalyst and pH = 3), 98.7% phenol degradation efficiency was achieved in 60min, as well as 71.6% TOC removal after 150min. Hydroxyl radical was identified as the main oxidizing agent involved on the cleavage of the phenol molecule. After four consecutive reuse cycles, phenol degradation efficiency was around 80%, indicating good reusability and stability of the catalyst. Therefore, the obtained results demonstrated that the bottom ash presents remarkable activity for application in the Fenton reaction towards phenol degradation.