Bisphenol A Degradation Research Articles

Bacterial bioremediation as a sustainable strategy for the mitigation of Bisphenol-A.

In the era dominated by plastic, the widespread use of plastic in our daily lives has led to a growing accumulation of its degraded byproducts, such as microplastics and plastic additives like Bisphenol A (BPA). BPA is recognized as one of the earliest man-made substances that exhibit endocrine-disrupting properties. It is frequently employed in the manufacturing of epoxy resins, polycarbonates, dental fillings, food storage containers, infant bottles, and water containers. BPA is linked to a range of health issues including obesity, diabetes, chronic respiratory illnesses, cardiovascular diseases, and reproductive abnormalities. This study examines the bacterial bioremediation of the BPA, which is found in many sources and is known for its hazardous effects on the environment. The metabolic pathways for the breakdown of BPA in important bacterial strains were hypothesized based on the observed altered intermediate metabolites during the degradation of BPA. This review discusses the enzymes and genes involved in the bacterial degradation of BPA. The utilization of naturally occurring microorganisms is the most efficient and cost-effective method due to their selectivity of strains, ensuring sustainability.

Degradation of Bisphenol A Using Self-Excited Oscillating Jets in Synergy with Fenton and Periodate Oxidation: Experimental and Artificial Neural Network Modeling Study

Bisphenol A (BPA) is an environmental endocrine-disrupting compound that is resistant to conventional biological treatment, making it crucial to develop an oxidation process. This study introduces a novel hydrodynamic cavitation (HC) coupled with a Fenton + periodate (PI) oxidation system for the efficient degradation of BPA. By systematically examining the key parameters such as inlet pressure, Fe (II), H2O2, and PI concentration, it was found that HC performed optimally at a pressure of 0.5 MPa. A conversion of 98.14% was achieved within 60 min when the molar ratio of BPA, Fe (II), H2O2, and PI was approximately 1:1:5:1. Further analysis revealed that the gray correlation between H2O2 and PI concentrations on the degradation efficiency was 0.833 and 0.843, respectively, indicating that both of them had significant effects on the degradation process. The free radical quenching assay confirmed the hydroxyl radical (•OH) as the main active substance. Additionally, the toxicity of the degradation intermediates was evaluated using the Toxicity Estimation Software Tool (TEST). An artificial neural network (ANN)-based model was constructed to predict the BPA-degradation process, facilitating precise reagent dosing and providing robust support for the intelligent application of water-treatment technologies.

Constructing heterointerfaces to enhance electron transfer of CoFe/CoFe2O4 mediated electro-Fenton process for bisphenol A degradation: Mechanistic insights and performance evaluation

The inefficient electron transfer and Fe(III)/Fe(II) cycle remain significant obstacles in the electro-fenton process. Herein, a nitrogen-doped graphite felt (NGF)-supported CoFe/CoFe2O4 heterostructure is synthesized that achieves highly efficient interfacial electron transfer and stable Co/Fe redox cycle. Theoretical calculations demonstrate that the CoFe/CoFe2O4 heterointerfaces induce local charge redistribution benefiting from the electronic communication between electron acceptor (CoFe2O4) and electron donor (CoFe). Analysis of the Fermi level indicates that the introduction of CoFe alloy enhances the electron density of the catalyst. The CoFe/CoFe2O4@NGF cathode can remove bisphenol A (BPA) completely in 90 min, and the pseudo-first-order kinetic constant (0.0625 min−1) is 23 times higher than the GF system. Notably, the CoFe/CoFe2O4@NGF electrode maintains excellent catalytic capability and stability within a broad pH range (3–11). The construction of the CoFe/CoFe2O4 heterostructure reduces the adsorption energy of oxygen, which ultimately increases the yield of reactive oxygen species (ROS). Quenching experiments revealed that hydroxyl radical (·OH) played a dominant role in the degradation of BPA, and significantly reduced the biotoxicity of intermediate products. This work offers a dependable approach for developing bimetallic catalysts with high catalytic activity.

Activating Fenton-like reaction by hydrochars containing persistent free radicals derived from various pomelo peel components

To reveal the influence of the diversity of precursors on the formation of environmental persistent free radicals (EPFRs), pomelo peel (PP) and its physically divided portion, pomelo cuticle (PC), and white fiber (WF) were used as precursors to prepare six hydrochars: PPH-Fe, PCH-Fe, WFH-Fe, PPH, PCH, and WFH with and without Fe(III) addition during hydrothermal carbonization (HTC). PPH-Fe and WFH-Fe had higher EPFRs content (9.11 × 1018 and 8.25 × 1018 spins·g−1) compared to PPH and WFH (3.33 × 1018 and 2.96 × 1018 spins·g−1), indicating that iron-doping favored EPFRs formation. However, PCH-Fe had lower EPFRs content (2.78 × 1018 spins·g−1) than PCH (7.95 × 1018 spins·g−1), possibly due to excessive iron leading to the consumption of the generated EPFRs. For another reason, the required Fe(III) amount for EPFRs formation might vary among different precursors. PC has a lower concentration of phenolic compounds but 68–97% fatty acids, while WF and PP are rich in cellulose and lignin. In the Fenton-like reaction, oxygen-centered radicals of hydrochar played a significant role in activating H2O2 and efficiently degrading bisphenol A (BPA). Mechanisms of reactive oxygen species (ROS) generation in hydrochar/H2O2 system were proposed. EPFRs on hydrochar activate H2O2 via electron transfer, creating ·OH and 1O2, leading to BPA degradation. More importantly, the embedded EPFRs on the hydrochar's inner surface contributed to the prolonged Fenton-like reactivity of PPH-Fe stored for 45 days. This study demonstrates that by optimizing precursor selection and iron doping, hydrochars can be engineered to maximize their EPFRs content and reactivity, providing a cost-effective solution for the degradation of hazardous pollutants.Graphical abstract

Multi-win situation of wastewater purification, carbon emission reduction and resource utilization: Conversion of refractory organics and nitrate to urea and ammonia in a flow-through electrochemical integrated system

The advanced oxidation process is an efficient technology for the degradation and detoxification of refractory organics to ensure water safety. However, most researches focus on improving pollutant degradation but overlook carbon emission and resource utilization. In this study, a flow-through electrochemical integrated system was constructed to simultaneously realize bisphenol A (BPA) oxidation into small non-toxic organics and CO2, and generated CO2 coupled with nitrate-containing wastewater conversion to urea and ammonia on a porous cathode (Zr-Fe/CN). The synergistic effect between anodic BPA oxidation with cathodic CO2 and NO3−reduction improves the electron utilization efficiency and thus increasing the BPA degradation, urea yield rate (UYR) and NH3 yield rate (NYR) by 13.4 % 18.4 % and 8.3 %, respectively. Furthermore, the flow-through operation mode significantly increased the mass transfer efficiency and quickly carried generated CO2 from the anode into the cathode to improve CO2 utilization efficiency. Compared to the parallel plate electrode reactor, the BPA degradation efficiency, UYR and NYR in the flow-through reactor increased from 59.46 % to 84.49 % (the initial concentration of BPA was 40 mg/L), 9.94 mmol h−1g−1 to 19.55 mmol h−1g−1, and 80.31 mmol h−1g−1 to 106.06 mmol h−1g−1 within 60 min, respectively. Moreover, the total carbon conversion efficiency (from BPA to urea) increased from 20.2 % to 42.4 % and the total Faraday efficiency (FE) increased from 78.6 % to 96.3 %. This work provides a multi-win strategy of harmless, resource-based and carbon emission reduction for wastewater treatment.

Efficient and stability electrochemical degradation of Bisphenol A on Ti/TiO2-NTA/PbO2-Nd anode: Mechanistic analysis

The Ti/TiO2-NTA/PbO2-Nd electrodes were fabricated using anodic oxidation and electrodeposition techniques for the electrocatalytic treatment of bisphenol A (BPA) pollutants in coking wastewater. Characterization revealed well-organized TiO2 nanotube arrays (TiO2-NTA) with a hollow structure, featuring a wall thickness of 36 nm and an inner diameter of approximately 83 nm. The TiO2-NTA interlayer restricted PbO2 growth, leading to a compact crystal structure and increased electrode surface area. Electrochemical tests showed that the Ti/TiO2-NTA/PbO2-Nd electrode outperformed Ti/TiO2-NTA/PbO2 and Ti/PbO2 electrodes, exhibiting the highest oxygen evolution potential, lowest charge transfer resistance, optimal hydroxyl radical generation, and longest service lifetime. The removal efficiencies for BPA were 95.4 % for Ti/TiO2-NTA/PbO2-Nd, 90.8 % for Ti/TiO2-NTA/PbO2, and 80.6 % for Ti/PbO2. The Ti/TiO2-NTA/PbO2-Nd electrode also achieved the lowest energy consumption at 0.157 kWh/(g·COD), a 40 % reduction compared to Ti/PbO2. The introduction of TiO2-NTA enhanced electrode stability, electron transfer, and surface area, while neodymium (Nd) doping improved oxygen evolution potential and hydroxyl radical production. Under optimized conditions, the Ti/TiO2-NTA/PbO2-Nd electrode achieved BPA removal efficiencies of 99.24 %, COD removal efficiencies of 82.77 %, and TOC removal efficiencies of 78.92 %. UV–Vis spectrophotometry, three-dimensional excitation-emission matrix fluorescence spectra (3D EEM), and gas chromatography–mass spectrometry (GC–MS) analyses revealed potential BPA degradation pathways.

Optimized microbial fuel cell-powered electro-Fenton processes to enhance electricity and bisphenol A removal by varying external resistance and electrolyte concentrations

This study is the first to investigate the effects of external resistance and electrolyte concentration on the performance of a bioelectro-Fenton (BEF) system, involving measurements of power density, H2O2 generation, and bisphenol A (BPA) removal efficiency. With optimized operating conditions (external resistance of 1.12 kΩ and cathodic NaCl concentration of 1,657 mg/L), the BEF system achieved a maximum power density of 38.59 mW/m2, which is about 3.5 times higher than with 1 kΩ external resistance and no NaCl. This system featured a 71.7 % reduction in total internal resistance. The optimized BEF also accelerated the oxygen reduction reaction rate, increasing H2O2 generation by 4.4 times compared to the unoptimized system. Moreover, it exhibited superior BPA degradation performance, removing over 99 % of BPA within 14 hs, representing a 1.1 to 3.3-fold improvement over the unoptimized BEF. By the fifth cycle (70 h), the optimized BEF still removed 70 % of BPA. Optimizing the operating conditions significantly increased the abundance of electrochemically active bacteria (Pseudomonadaceae) from 2.2 % to 20 %, facilitating rapid acclimation. The study demonstrates the strong potential of an optimized BEF system for removing persistent pollutants.

Application of novel dual-ligand co metal-organic framework/graphene oxide for electrocatalytic oxidative degradation of bisphenol A in marine wastewater

The adjustment of the electron distribution of 2D metal-organic frameworks (2D-MOFs), as a hot anode candidate for electrocatalytic oxidation, is crucial for its application. In this work, a new electron distribution was achieved with dual-ligand connection and graphene oxide (GO) loading and the complex of dual-ligand 2D-MOF/GO (Co-IH/GO) exhibit faster electron transfer efficiency (Rct = 62.5) and more active sites (ID/IG = 1.01). Co-IH/GO demonstrated excellent electrocatalytic performance and achieved 100 % electrocatalytic degradation of bisphenol A (BPA) within 10 min. In addition, superior properties of stability, temperature tolerance, and pH tolerance were achieved, after 5 cycles of degradation, the catalyst was able to maintain 100 % degradation efficiency, Capable of maintaining good degradation performance over a temperature range of 25 °C–45 °C and a wide pH range of pH = 5–11. Both experimental and electron paramagnetic resonance analysis results indicated that 1O2 acted as the dominant active substrate. With the involvement of Cl− in marine wastewater, activated chlorine was also generated during the reaction, which contributed to fast BPA degradation. Furthermore, the established dual-ligand 2D-MOF/GO electrocatalytic system exhibited superior activity for the degradation of dyes and complex microflora, while the solar-driven degradation experiment shed light on the independence of fossil and stationary sources of energy.

Biodegradation of bisphenol-A in water using a novel strain of Xenophilus sp. embedded onto biochar: Elucidating the influencing factors and degradation pathway

Bisphenol-A (BPA) is an emerging hazardous contaminant, which is ubiquitous in the environment and can cause endocrine disruptor and cancer risks. Therefore, biodegradation of BPA is an essential issue to mitigate the associated human health. In this work, a bacterial strain enables of degrading BPA, named BPA-LRH8 (identified as Xenophilus sp.), was newly isolated from activated sludge and embedded onto walnut shell biochar (WSBC) to form a bio-composite (BCM) for biodegradation of BPA in water. The Langmuir maximum adsorption capacity of BPA by WSBC was 21.7 mg g−1. The free bacteria of BPA-LRH8 showed high BPA degradation rate (∼100 %) at pH 5–11, while it was lower (＜20 %) at pH 3. The BCM eliminated all BPA (∼100 %) at pH 3–11 and 25–45 °C when the BPA level was ≤ 25 mg L−1. The spectrometry investigations suggested two possible degradation routes of BPA by Xenophilus sp. In one route, BPA (C15H16O3) was oxidized to C15H16O3, and then broken into C9H12O3 through chain scission. In another route, BPA was likely hydroxylated, oxidized, and cleaved into C9H10O4P4, which was further metabolized into CO2 and H2O in the TCA cycle. This study concluded that the novel isolated bacteria (BPA-LRH8) embedded onto WSBC is a promising and new method for the effective removal of BPA and similar hazardous substances from contaminated water under high concentrations and wide range of pH and temperature.

Degradation of emerging contaminants in synthetic hydrolyzed urine by UV/peracetic acid: Free radical chemistry, and toxicity analysis

The ecological impact of emerging contaminants (ECs) in aquatic environments has raised concerns, particularly with regards to urine as a significant source of such contaminants in wastewater. The current investigation used the UV/Peracetic Acid (UV/PAA) processes, an innovative advanced oxidation technology, to effectively separate two emerging pollutants from urine at its source, namely, ciprofloxacin (CIP) and bisphenol A(BPA). The research findings demonstrate that the presence of the majority of characteristic ions has minimal impact on the degradation of ECs. However, in synthetic hydrolyzed urine, only NH4+ inhibits the degradation of two types of ECs, with a more pronounced effect observed on CIP degradation compared to BPA.The impact of halogen ions, specifically Cl− and I−, on the degradation of CIP in synthetic hydrolyzed urine was a complex phenomenon. When these two halogen ions are present individually, the generation of reactive halogen species (RHS) within the system enhances the degradation of CIP. However, when both types of ions coexist, the formation of diatomic radical species partially inhibits degradation. In terms of BPA degradation, while the production of reactive chlorine species (RCS) to some extent hinders the reaction rate, the generation of reactive iodine species (RIS) promotes the overall process. CIP undergoes fragmentation of the piperazine and quinoline rings, decarboxylation, defluorination reactions, as well as substitution reactions, leading to the formation of products with simplified structures. The degradation of BPA occurs gradually through hydroxyl and halogen substitution as well as isopropyl cleavage. The preliminary toxicity analysis confirmed that the presence of halogen ions in urine resulted in the formation of halogenated products in two types of ECs, albeit with an overall reduction in toxicity. The UV/PAA processes was considered to be an effective and relatively safe approach for the separation of ECs in urine.

Electron cycling mechanism in Fe/Mn DSAzyme accelerates BPA degradation and nanoenzyme regeneration

Peroxidase-like (POD-like) as a kind of new Fenton-like catalyst can effectively activate H2O2 to degrade organic pollutants in water, but improving the catalytic activity and stability of POD-like remains a challenging task. Here, we synthesized a novel dual single-atom nanoenzyme (DSAzyme) FeMn/N-CNTs with Fe-N4 and Mn-N4 bimetallic single-atom active centers by mimicking the active centers of natural enzymes and taking advantage of the synergistic effect between the dual metals. FeMn/N-CNTs DSAzyme showed significantly enhanced POD-like activity compared to monometallic-loaded Fe/N-CNTs and Mn/N-CNTs. Within the FeMn/N-CNTs/H2O2 system, bisphenol A (BPA) could be removed 100 % within 20 min. DFT calculations show that Mn-N4 in FeMn/N-CNTs can readily adsorb negatively charged BPA molecules and capture electrons. Meanwhile, Fe-N4 sites can easily adsorb H2O2 molecules, leading to their activation and splitting into strongly oxidizing hydroxyl radicals (·OH). Throughout this process, electrons are continuously recycled in BPA → Mn-N4 → Fe-N4 → H2O2, effectively promoting the regeneration of Fe2+. Practical studies on wastewater and cycling experiments have demonstrated the great potential of this method for remediating water environments.

Synthesis of strongly interactive FeWO4/BiOCl heterostructures for efficient photoreduction of CO2 and piezo-photodegradation of bisphenol A

Development of multi-functional photocatalysts for CO2 reduction and pollutant elimination is practically significant for solving the environmental problems and energy shortages. In this study, we have immobilized FeWO4 (FWO) nanoparticles on the surface of (001)-facet-exposed BiOCl (BOC) nanosheets through their strong electrostatic interaction to form FWO/BOC heterojunctions. Experimental and theoretical studies corroborate that the FWO/BOC heterojunctions exhibit high-efficiency Z-scheme transfer and separation of photocarriers, and possess excellent photocatalysis for CO2 reduction and bisphenol A (BPA) degradation. Under simulated-sunlight irradiation, the 9 %FWO/BOC heterojunction exhibits a photoreduction performance with CH4/CO yield rates of 4.25/9.41 μmol g−1 h−1 (5 h reaction), which are 3.86/5.26 times higher than those for bare BOC; whereas its photodegradation performance (η(60 min) = 66.8 %, kapp = 0.01755 min−1) is enhanced by 4.3 and 2.7 times compared with that of bare FWO and BOC, respectively. Furthermore, when ultrasonic vibration is simultaneously employed during the simulated-sunlight illumination, the ultrasonic-induced piezoelectric polarization field in BOC nanosheets accelerates the bulk photocarrier separation, resulting in a further improvement in the BPA degradation, and the calculated SF = 1.79 quantifies the degree of enhancement achieved by piezo-photocatalysis collaboration. The introduction of a moderate amount of H2O2 or peroxymonosulfate (PMS) in the reaction solution plays a significant role in promoting the BPA degradation due to the generation of additional •OH and •SO4− reactive species. The mechanisms for photocatalytic CO2 reduction and piezo-photodegradation of BPA catalysis were deeply studied by combining experiments and theory.

Photodegradation of bisphenol A (BPA) in coastal aquaculture waters: Influencing factors, products, and pathways

Bisphenol A (BPA), an endocrine-disrupting contaminant, is ubiquitous in the environment due to its presence in plastics, wastewater, and agricultural runoff. This study investigated the photodegradation behavior of BPA in coastal aquaculture waters near Qingdao, China. Lower salinity promoted BPA photodegradation, while higher salinity has an inhibitory effect, suggesting slower degradation in seawater compared to ultrapure water. Triplet-excited dissolved organic matter (3DOM*) was identified as the primary mediator of BPA degradation, with additional contributions from hydroxyl radicals (•OH), singlet oxygen (1O2), and halogen radicals (HRS). Alepocephalidae aquaculture water exhibited the fastest degradation rate, likely due to its high DOM and nitrate/nitrite (NO3−/NO2−) content, which are sources of 3DOM* and •OH. A positive correlation existed between NO3−/NO2− concentration and the BPA degradation rate. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) analysis identified the primary BPA photodegradation products, formed mainly through oxidative degradation, hydroxyl substitution, nitration, and chlorination pathways. Elucidating these photodegradation mechanisms provides valuable insights into the environmental fate and potential ecological risks of BPA in aquaculture environments. This knowledge can inform strategies for marine environmental protection and the development of sustainable practices.

Efficacy of BPNS/TiO2 in catalyzing the visible-light-driven degradation of BPA

A novel composite material consisting of black phosphorus nanosheets (BPNS) and titanium dioxide (TiO2) for degrading bisphenol A (BPA) under visible light was investigated. Through a series of photocatalytic experiments and characterization techniques, we found that BPNS/TiO2 composite materials exhibit excellent BPA degradation ability under visible light irradiation, are capable of degrading 85 % of BPA, and can degrade up to 88.72 % of BPA in acidic environments. The synergistic effect of the composite, combined with the advantages of BPNS, increases the light absorption capacity of TiO2. The introduction of TiO2 can reduce the photogenerated electron-hole pair recombination ability of the composite material and improve the carrier migration ability of the composite material, making it an efficient and environmentally friendly catalyst for BPA degradation. We identified and characterized intermediate products of BPA degradation using high-performance liquid chromatography–mass spectrometry (HPLC–MS) and other study. This process elucidates the potential degradation pathways. The results of this study provide strong support for addressing BPA pollution in the environment and offer a new scientific foundation for the application of photocatalysis technology in environmental protection and wastewater treatment.

Enhanced Selective Degradation of Pharmaceutical and Personal Care Products by β-Cyclodextrin-Decorated ZIF-67 Nanocomposites in Reclaimed Water.

A peroxymonosulfate oxidation system was developed via modification of β-cyclodextrin (β-CD) on the surface of Fe2+-doped ZIF-67 (CD/Fe@ZIF-67) as an activator. The 99.7% carbamazepine, 91.3% bisphenol A (BPA), and 95.4% diclofenac (DCF) degradation efficiency were achieved within 10 min, 60, and 1 min, respectively. The hydrophobicity of these three pollutants is positively correlated with their adsorption kinetic constants by CD/Fe@ZIF-67 due to the introduction of β-CD. Scavenger experiments and electron spin resonance spectra confirmed that carbamazepine was preferentially oxidized by SO4•- [λ(SO4•-)(70.5%) > λ(•OH)(28.2%) > λ(O2•-)(1.3%)], where SO4•- and O2•- played dominant roles in the degradation of BPA [λ(SO4•-)(71.7%) > λ(O2•-)(22.8%) > λ(•OH)(5.5%)], and O2•- was responsible for DCF removal [λ(O2•-) = 93.2%]. Additionally, the particulate catalyst was immobilized in the shell side of a ceramic membrane in a membrane reactor for catalyst recovery. This reactor achieved nearly 100% removal efficiency under optimal conditions: 0.036 wt % catalyst loading, 0.5 mM peroxymonosulfate concentration, 1 L inflow, 10 mg/L initial carbamazepine concentration, and 0.012 L/min hydraulic retention time. In summary, this study elucidates the active role of β-CD in a polymetallic/peroxymonosulfate system and provides valuable insights into the development of effective oxidation methods for pharmaceutical and personal care products in wastewater.

Enhanced mineralization of bisphenol A by electric arc furnace slag: Fenton-like oxidation

Bisphenol A (BPA) aqueous solution was treated through a heterogeneous Fenton-like oxidation process with electric arc furnace slag (EAFS), a waste product from an Argentinian steel processing plant, as the catalyst. SEM/EDS, XRD, and Mössbauer spectroscopy characterization revealed a significant presence of Fe and minor amounts of Cu and Mn in EAFS, known to play active roles in the Fenton-like reactions. The predominant crystalline form of iron in EAFS was magnesiowüstite, accompanied by minor amounts of hematite, magnetite, maghemite, and metallic iron. Batch Fenton-like oxidation experiments were conducted under acidic conditions (pH 2.8–3), examining the effect of temperature (25, 50, and 70 °C) and catalyst load (0.1, 0.5, and 1 g/L) on BPA degradation and mineralization over 180 min. BPA was completely degraded within the first minutes, while mineralization levels improved from 40% to an outstanding 70% as the temperature increased from 25 to 70 °C. The catalyst gradually lost its activity after five cycles at 25 °C, but raising the temperature up to 70 °C allowed maintaining mineralization levels between 70 and 50% over ten cycles. The oxidation process involved a combined Fenton-like homogeneous/heterogeneous mechanism, and deactivation was linked to a lower leaching of active cations over the cycles, reduction of the Fe(II)/Fe(III) ratio in the iron phases, and blocking of active sites by adsorption of reaction intermediates. EAFS demonstrated an exceptional performance in the Fenton-like oxidation of BPA. The utilization of this type of industrial waste materials represents a promising technological alternative that could benefit both steel processing and water treatment plants.

Degradation of bisphenol A via the electro–Fenton process using nanostructured carbon-metal oxide anodes: Intermediates and reaction mechanisms study

The removal of the bisphenol A (BPA) from sulphate-rich wastewater has been investigated using an electro-Fenton oxidation system with metal-oxide carbon nanostructured anode. The process produces highly oxidizing species, including hydroxyl radicals on the anode surface and bulk solution via an electrochemically monitored Fenton reaction. The focus of this research is the detection of BPA intermediates and the prediction of the BPA degradation mechanism during the electro-Fenton process using the SnO2-MWCNT nanostructured anode. In accordance to detected reactive oxygen species, BPA intermediates, and their respective peak area profiles, two primary degradation pathways can be defined. Whether direct cleavage of BPA precedes hydroxylation, oxidation, and dealkylation, or vice versa, the resulting products consist of catechols, dicatechols, quinones, aldehydes, carboxylic acids, and ultimately carbon dioxide and water. To ensure a comprehensive understanding, the impact of applied current, catalyst concentration, and treatment duration on degradation and mineralization efficiency, as well as degradation kinetics, was investigated. The degradation of BPA was found to follow pseudo-first-order reaction kinetics. The results showed that the degradation of BPA was attributed to the co-action of electro-Fenton oxidation and electrochemical oxidation. This study confirms the eco-friendly nature of the electro-Fenton process by demonstrating the toxicity of intermediaries formed during BPA treatment.

Zn-Mn bimetallic oxide derived from waste battery to activate peroxymonosulfate for bisphenol A removal under visible light irradiation

In this study, Zn-Mn bimetallic oxide (ZMBO) was synthesized from spent alkaline zinc-manganese batteries to effectively activate peroxymonosulfate (PMS) under visible light irradiation. PMS activation can be triggered by Mn-composition, which could be augmented thanks to the visible light response of Zn-composition. Meanwhile, the introduction of PMS could effectively hinder the rapid recombination of photogenerated electron-hole pairs. By adding 1.00 mM of PMS and 0.50 g/L of ZMBO, the Vis/ZMBO/PMS system could remove 90.0 % of bisphenol A (BPA) in 120 min under the neutral pH condition. Quenching experiment and electron paramagnetic resonance technique were used to identify the reactive species, and singlet oxygen as well as photogenerated hole were identified as the major reactive species which exhibited high selectivity towards electron-rich contaminants. X-ray photoelectron spectroscopy (XPS) confirmed that the cycles between manganese in Mn(II), Mn(III) and Mn(IV) promoted PMS activation. The ZMBO photocatalyst exhibited excellent reusability. The existence of common anions (Cl–, NO3– and SO42–) presented a slight inhibition for BPA degradation while little BPA was removed with the addition of 5.00 mM H2PO4–. This study provides an alternative for the feasible utilization of waste battery, and the Vis/ZMBO/PMS system shows great potential in the elimination of pollutant with electron-donating capability from water.

Combination of hydrodynamic cavitation with CoFe2O4 photocatalyst for activation of peracetic acid under UVC irradiation in synergistic degradation of bisphenol A

This study was aimed at activating peracetic acid (PAA) to degrade bisphenol A (BPA) in aqueous media by combining a system of hydrodynamic cavitation (HC) with CoFe2O4 photocatalyst under UVC irradiation. The CoFe2O4 was successfully synthesized and characterized by various characterization techniques. The influence of various HC approaches alone and combined with photocatalysis on the BPA degradation was explored. After 60 min reaction, the BPA degradation efficiency achieved by CoFe2O4, UV, HC, and PAA individually was 0.69 %, 2.77 %, 6.45 %, and 14.23 %, respectively. At same experimental conditions, under the CoFe2O4 + HC + UV, CoFe2O4 + HC + PAA, CoFe2O4 + UV + PAA and CoFe2O4 + HC + UV + PAA processes, BPA degradation rates were 68.47 %, 77.91 %, 84.23 % and 97.29 %, respectively. The BPA degradation efficiency was examined under various operational parameters, including pH (3−11), BPA concentration (20–40 mg/L), load of CoFe2O4 (0.1–0.4 g/L), PAA dosage (50–200 μmol/L), inlet pressure (1.0–4.0 bar), and reaction time (0–60 min). 97.29 % BPA was degraded over 60 min in the ideal reaction conditions (pH: 7.0, BPA: 20 mg/L, CoFe2O4: 0.4 g/L, PAA: 200 μmol/L, inlet pressure:4.0 bar). BothO·Hradicals and R−O.were contributed to BPA reaction system, andO·Hplayed as the dominant contributor. Overall, CoFe2O4 + HC + UV + PAA system provides a low-energy and low-cost strategy for degrading and mineralizing organic contaminants from waters.

Peracetic acid activation by natural magnetite for bisphenol A degradation: Performance and degradation mechanism

Advanced oxidation processes based on activated peracetic acid (PAA) have been widely used in water treatment. In this study, magnetite was first employed in PAA activation for Bisphenol A (BPA) degradation. The results showed that the magnetic/PAA system degraded 94.6 % BPA in 60 min at neutral pH (pH = 6.7), exhibiting a higher rate constant (kobs = 0.051 min−1) than PAA or magnetite alone. X-ray photoelectron spectroscopy (XPS) results proved that ≡Fe(II) and surface hydroxyl group (OOH) were the dominant active sites, which promoted the electron transfer between magnetite, PAA, and BPA. According to the scavenging experiments and electron paramagnetic resonance (EPR) spectrum, the main reactive oxygen species responsible for BPA degradation include organic radicals (CH3COOO), Hydroxyl radical (OH) and singlet oxygen (1O2). The BPA degradation pathway was determined by LC-MS analysis, and the toxicity of the intermediates was evaluated by ECOSAR and wheat seed growth inhibition experiment. In addition, the magnetite/PAA system presented a good adaptability under a wide initial pH range, demonstrating efficient degradation even in the presence of complex matrices such as Cl−, NO3− or humic acid in water bodies while HCO3− and H2PO4− inhibited BPA degradation. This study not only reveals the mechanism of magnetite activating PAA but also provides a new idea for applying magnetite in PAA-based AOPs to remove micropollutants in wastewater.