Bisphenol AF Degradation Research Articles

Ultrasound-assisted bisphenol AF degradation using in situ generated hydrogen peroxide

Bisphenol AF (BPAF) is degraded through the ultrasound-assisted in situ generation and activation of hydrogen peroxide (H2O2) by the copper(II) catalysed oxidation of hydroxylamine (NH2OH) with dioxygen (O2). Compared to added H2O2, in situ generated H2O2 significantly improves the degradation of BPAF from 46.7% to 94.8% in ∼15 min. The reaction follows a pseudo-first-order kinetic model. This study examines the influence of solution pH, anions, humic acid, and different concentrations of the reactants on BPAF degradation. Mass spectrometry was used to identify the BPAF degradation products, and a degradation pathway is proposed. This work advances the understanding of in situ hydrogen peroxide generation and activation in advanced oxidation (Fenton-like) processes (AOPs).

Perovskite oxide nanoparticles: Dual role as supports for luminescent Eu(III) ions and photocatalysts for bisphenol degradation

Perovskite oxides, such as CaTiO3, SrTiO3, and BaTiO3, have gained significant recognition for their dual role as luminescence supports and photocatalytic materials. In this study, we synthesized perovskite oxide nanoparticles (NPs) using the thermal calcination method and employed them as photocatalysts for the degradation of bisphenol S (BPS) and bisphenol AF (BPAF) under UVC irradiation. The as-synthesized photocatalysts were thoroughly examined for the photocatalytic degradation process and identified secondary products were identified using liquid chromatography in conjunction with high-resolution mass spectrometry. Our observations highlighted the relatively faster photocatalytic degradation of BPS compared to BPAF. Notably, among the perovskite oxide materials, SrTiO3 exhibited the highest catalytic activity for BPS degradation, while BaTiO3 outperformed in the case of BPAF degradation. Perovskite oxide NPs were also utilized as supports for doping with Eu3+ ions to create phosphor supports. Luminescent emissions from the Eu3+ ions, characterized by the 5D0 → 7FJ = 0-4 transitions, were observed and varied depending on the support material. Notably, Eu3+ doped in CaTiO3 nanoparticles exhibited the highest luminescence efficiency. These results highlight the dual functionality of perovskite oxide-based materials in phosphor applications and photocatalysis, offering valuable insights into their potential for both enhancing luminescence efficiency and treating bisphenols.

Heat enhanced bisphenol AF degradation in CoFe2O4@BC activated peroxymonosulfate process: Mechanism and the role of inorganic anions

Carbon-based materials and heat activated peroxymonosulfate (PMS) have emerged as promising technologies for the remediation of contaminated water. This study investigated the feasibility of Bisphenol AF (BPAF) degradation by coupling CoFe2O4@BC catalyst with heat activated PMS technology. Heat significantly enhanced the catalytic performance of CoFe2O4@BC for PMS activation, resulting in 87.0 % removal of BPAF. Meanwhile, the effects of PMS concentration, CoFe2O4@BC catalyst dosage, initial pH, and the inorganic anions on BPAF degradation were investigated. The presence of HCO3− and HPO42− were found to enhance BPAF degradation by promoting PMS decomposition, while humic acid (HA) significantly inhibited BPAF removal. Electron paramagnetic resonance (EPR) and quenching experiments suggested that sulfate radicals (SO4•−) were the dominant reactive oxygen species (ROS) in the system, with hydroxyl radicals (•OH) and singlet oxygen (1O2) also contributing to BPAF degradation. Based on the Density Functional Theory (DFT) and intermediates analysis, two degradation pathways of BPAF were proposed, including hydroxylation and β-scission reactions. This work reveals the underlying mechanism of PMS activation under the coupling of heat with the CoFe2O4@BC system and presents a potential method for contaminants decomposition.

Three-dimensional hollow catalysts with edge-defective Fe-Nx sites and enhanced peroxymonosulfate activation performance: Preparation, applications, and mechanism

Developing heterogeneous catalysts with high level of active site exposure is crucial for the activation of peroxymonosulfate. In this study, a series of high-performance Fe-N-C catalysts were obtained through the strategy of melamine-assisted pyrolysis. The morphology, specific surface area and pore structure of the catalysts can be adjusted by controlling the amount of melamine added during the pyrolysis process. Fe1-Nx-C obtained with a melamine to Fe-ZIF ratio of 1:1 exhibited the highest specific surface area (984.2 m2·g−1), pore volume (1.79 cm3·g−1) and reaction rate constant (0.055 min−1, 5.5 times that of Fe0-Nx-C). Furthermore, Fe1-Nx-C showed high stability and reusability in multiple cycles, maintaining high catalytic activity with pH range of 3–9. The addition of melamine can cause selective cleavage of C-N bonds, converting the central Fe-Nx sites into more active edge-defective Fe-Nx sites, thereby enhancing the catalytic activity. Quenching experiments and electron paramagnetic resonance (EPR) detection confirmed the dominance of 1O2 in the degradation of Bisphenol AF (BPAF). Two possible pathways for BPAF degradation were proposed based on liquid chromatography-mass spectrometry (LC-MS) and density functional theory (DFT) calculations. This study provides a new way to design and construct Fe-N-C catalysts with ideal pore structures, and enhance the accessibility of active sites inside the catalysts.

Treatment of bisphenol pollutant in water by N,P-co-doped carbon nanosheet: Fast degradation, toxicity elimination and reaction mechanism investigation

Metal-free carbon catalysts perform well in peroxymonosulfate-based advanced oxidation process for the treatment of organic pollutant-containing wastewater. Herein, a natural biomolecule of adenosine triphosphate (ATP), containing abundant N and P elements, served as sole precursor to prepare N,P-co-doped carbon through one-step anoxic pyrolysis, which was applied as peroxymonosulfate activator to treat bisphenol-contaminated water. Owing to the endogenous N and P elements in ATP, in-situ doping was achieved for the prepared carbon material with excellent doping effect, such as high doping amount and numerous defects. During pyrolysis process, the generated gases facilitated the exfoliation of carbon structure, resulting in a nanosheet-like morphology with large specific surface area, e.g., 852.75 m2 g−1 for NPCN-900 sample obtained at 900 °C. Benefiting from the structural modulation brought by N,P co-doping, typical sample of NPCN-900 presented excellent catalytic performance towards bisphenol AF (BPAF) degradation through PMS activation. An apparent reaction rate constant of 0.4115 min−1 was calculated under the investigated reaction conditions. Further studies indicated that 1O2, surface-bound •OH and SO4−• worked together in NPCN-900/PMS system for BPAF degradation. Graphitic N, pyrrolic N, CO groups, defect structure and the doped P atoms in NPCN-900 contributed to PMS activation. It was also important that the toxicity of BPAF solution could be preliminarily eliminated after treatment by NPCN-900/PMS system, which was verified by ecotoxicity assessments through ECOSAR program and green algae growth experiments.

Zero valent copper-mediated ferrate (Ⅵ) for the degradation of bisphenol AF

This study presented a novel zero valent copper-mediated ferrate (VI) oxidation system for the degradation of bisphenol AF (BPAF). The effect of various factors (such as the dosage of ZVC, the concentration of ferrate(VI), the reaction temperature, the initial pH of reaction solution, inorganic anions and HA) on the BPAF degradation process was investigated. It was discovered that ZVC had a good catalytic effect on ferrate(VI), with a removal efficiency of 92.4% achieved in 3 min under a standard condition([ZVC]0 =50 mg/L, [Fe(Ⅵ)]0 = 30 μM, [BPAF]0 = 3 μM, [pH]0 = 7, T = 25 ℃). Nitrate ions (NO3-) have no obvious effect on the degradation of BPAF. Sulfate ions (SO42-) promoted BPAF degradation at low concentrations but inhibited it at high concentrations, whereas different concentrations of chloride (Cl-) or bicarbonate ions (HCO3-) inhibited it. Furthermore, methyl phenyl sulfoxide (PMSO) was used as a probe to detect the presence of active species in this system. The results showed that the intermediate iron substances (Fe(IV)/Fe(V)) with strong oxidation ability and Fe(VI) completed the degradation of BPAF collectively. The use of zero-valent copper and ferrate (VI) provided a viable method for removing refractory organics from wastewater.

Novel sludge-sugarcane bagasse mixed biochar as an efficient activator for peroxymonosulfate to degrade bisphenol AF

The exploitation of cost-effective and environmentally friendly biochar catalysts is of major importance for the oxidative treatment of toxic organic wastewater and the resource utilization of waste biomass. In this work, sewage sludge and bagasse waste were co-pyrolyzed into a novel biochar catalyst (SB-BC-900) for efficiently activating peroxymonosulfate (PMS) to degrade bisphenol AF (BPAF) in wastewater. Compared with single sludge biochar (S-BC-900), SB-BC-900 had a larger cumulative pore volume, more oxygenated functional groups (OFGs) and higher graphitization degree, with a significantly higher catalytic capacity. SB-BC-900 enabled rapid degradation of BPAF within 10 min at a low PMS dosage (molar ratio [PMS]: [BPAF] = 2.67:1). There was mainly the non-free radical pathway dominated by singlet oxygen (1O2) in the SB-BC-900/PMS system. Graphitic carbon (sp2 C=C) and OFGs on SB-BC-900 played a crucial part in the catalytic degradation of BPAF. A green approach is provided to resource waste biomass for efficient wastewater treatment in this work.

Amino-modified metal–organic frameworks as peroxymonosulfate catalyst for bisphenol AF decontamination: ROS generation, degradation pathways, and toxicity evaluation

Advanced oxidation processes (AOPs) based on the metal–organic frameworks (MOFs) and peroxymonosulfate (PMS) have been demonstrated as promising methods for the degradation of contaminants. In this study, the degradation of bisphenol AF (BPAF) by activated PMS via amino-modified metal–organic frameworks (AMOF) was investigated thoroughly. BPAF could be efficiently removed (94.1%) in the optimal condition. The decontamination of BPAF could be accelerated significantly with the increasing temperature, and a highly stable degradation performance was observed at a wide pH range. Quenching experiments and electron paramagnetic resonance (EPR) tests revealed that sulfate radical (SO4–•), hydroxyl radical (HO•), singlet oxygen (1O2), and superoxide radical (O2–•) were produced synergistically in the AMOF/PMS system. Chloride ion (Cl–) exhibited a dual influence on BPAF removal, while other anions and NOM could hinder the degradation rate mildly. A total of fifty-two intermediates were identified using UHPLC-MS/MS method and four main degradation pathways were proposed based on the density functional theory (DFT) calculation, including the frontier molecular orbital theory (FMO), natural population analysis (NPA), and Fukui function. Finally, the Quantitative Structure Activity Relationship (QSAR) method for Toxicity Estimation Software Tool (TEST) was applied to estimate the accurate toxicity of BPAF and degradation byproducts. This study exhibited the promising potential for the decontamination of BPAF in the water via the AMOF based AOPs.

Designing S-scheme Au/g-C3N4/BiO1.2I0.6 plasmonic heterojunction for efficient visible-light photocatalysis

A novel S-scheme Au/g-C3N4/BiO1.2I0.6 plasmonic heterojunction was constructed by calcining a mixture of flower-like BiOI and Au/g-C3N4 nanosheets for the first time. This Au/g-C3N4/BiO1.2I0.6 heterojunction exhibited excellent photocatalytic activity in bisphenol AF (BPAF) degradation and Cr(VI) reduction with high cycle stability under visible light irradiation. In particular, the photocatalytic performance of the optimum material developed (4-Au/g-C3N4/BiO1.2I0.6) can reach 0.0174 min−1 (apparent rate of BPAF degradation) and 0.0204 min−1 (apparent rate of Cr(VI) reduction), which were 6.5 and 3.7 times that of pristine g-C3N4, respectively. The high photocatalytic performance was due to the high efficiency of charge separation, the excellent light absorption of localized surface plasmon resonance (LSPR) caused by the Au deposition, and the formation of S-scheme heterojunctions, which maintained strong photocatalytic reduction and oxidation activity. Noticeably, the charge density difference and band offsets of the g-C3N4/BiO1.2I0.6 were calculated. The results revealed that an internal electric field (IEF) was created, which further demonstrated the formation of an S-scheme photocatalytic mechanism.

Strongly enhanced Fenton-like oxidation (Fe/peroxydisulfate) by BiOI under visible light irradiation: A novel and green strategy for Fe(III) reduction

In order to accelerate the photo-Fenton reaction process of Fe(III) under visible light irradiation, BiOI was introduced into the Fe(III)/peroxydisulfate (PDS) system. The catalytic oxidation performance of vis-light/BiOI/Fe(III)/PDS system was evaluated using bisphenol AF (BPAF) as a representative organic contaminant. Within 30 min, nearly 100% of BPAF was degraded, proving that the system had an excellent ability to degrade organic pollutants in water. Free radical quenching experiments, electron spin resonance (ESR), and molecular probing experiments determined that the main reactive species in the system were hydroxyl radicals (•OH) and sulfate radicals (SO4•−). The comparative experiments showed that the degradation rates were closely related to the PDS consumption, while the Fe(II) absorbed on the surface of BiOI was responsible for the PDS consumption. The production pathway of Fe(II) was analyzed by XRD, FTIR and XPS characterization, the Fe(III) on the surface of BiOI was reduced by photogenerated electrons to generate Fe(II). The result confirmed that the reduction of Fe(III) by photogenerated electrons could effectively inhibit the recombination of electron-hole pairs, and accelerate the reduction progress of Fe(III)/Fe(II) cycle that was the rate-limiting step in PDS activation. Afterwards, a reliable mechanism for degradation of BPAF in visible light/BiOI/Fe(III)/PDS system was proposed. Finally, the influence of reactant dosages, visible light intensity, initial pH, humic acid (HA) and anions in the solution on the degradation of BPAF were discussed.

The Degradation of Bisphenol Af in Solar Light Assisted Periodate Process Based on Pristine Zno

The Degradation of Bisphenol Af in Solar Light Assisted Periodate Process Based on Pristine Zno

Nonradical induced degradation of bisphenol AF by NaBiO3 coupled peroxymonosulfate process: Performance and mechanism

It has been shown previously that the NaBiO3 (NBO) could efficiently photocatalytically degrade organic contaminants because of its excellent photocatalytic property. In this study, we proposed a heterogeneous catalytic system of NBO for peroxymonosulfate (PMS) without light irradiation. The results showed that NBO/PMS exhibited excellent performance toward bisphenol AF (BPAF) degradation and mineralization. The effectiveness of the NBO/PMS system was also investigated in different multicomponent systems. The effects of initial pH, NBO dosages, and PMS concentration for BPAF degradation were also investigated. Radical quenching experiments combined with electron spin resonance analysis indicated that singlet oxygen (1O2) was the main reactive oxygen species, and ·SO4- and ·OH– radicals participated in the process. X-ray photoelectron spectroscopy revealed the main catalytic mechanism: lattice oxygen (Ovac) was extruded during the transformation of Bi(V) to Bi(III) to form and activate oxygen (O*), and the generated O* between the [BiO6] regular octahedral layers reacted with PMS on the NBO surface to form 1O2. Based on the results of the Bi element, it is suggested that the activation process proceeded through electron transfer from NBO to PMS. The stability of NBO and applicability of the NBO/PMS system in a natural water environment were explored. This work provides a novel approach to PMS activation and the potential use of NBO for the decontamination of organic pollutants.

Degradation of bisphenol AF in water by periodate activation with FeS (mackinawite) and the role of sulfur species in the generation of sulfate radicals

The heterogeneous catalyst Mackinawite (FeS) was applied to activate periodate (IO4−) to degrade endocrine disruptors bisphenol AF (BPAF). This study investigated the influence of FeS dosage, periodate dosage, BPAF concentration, initial pH value and inorganic ions on BPAF degradation by FeS/IO4− system. The results showed that the BPAF was effectively degraded by FeS/IO4− system. The acidic pH exhibited higher efficiency in BPAF degradation compared with alkaline and neutral conditions. Furthermore, the BPAF degradation was dramatically promoted in the presence of Cl− and SO42−, whereas CO32− inhibited BPAF degradation. The radical scavenging tests and EPR indicated that singlet oxygen (1O2), superoxide radicals (O2−) and SO4− were committed to the degradation of BPAF, among which O2−, 1O2 were predominant radicals. The separate experiments showed that Fe(Ⅱ) participated in the activation of periodate. Furthermore, the effects of sulfur species (including the S2−, SO32−) on BPAF degradation by FeS/IO4− system were studied. The radical quenching tests suggested that S2− and SO32− were responsible for producing SO4−. The findings of this study elucidated an approach for the removal of micro-pollutants in the water environment through heterogeneous activation of periodate by FeS.

Heterogeneous catalytic oxidation degradation of BPAF by peroxymonosulfate active with manganic manganous oxide: Mineralization, mechanism and degradation pathways

In this study, the catalytic ability and mechanisms involved in activating peroxymonosulfate (PMS) with Mn3O4 and the degradation pathways of bisphenol-AF (BPAF) removal was investigated. SO4−• and ·OH which were explored by and scavenging tests were the major reactive radicals in the Mn3O4/PMS system. A simple simulation algorithm was also used to calculate the relative concentrations of SO4−• ([SO4−•]) and ·OH ([·OH]) which were 8.39 × 10 −15 M and 6.96 × 10 −13 M, respectively. The mechanism for the electron transfer between the Mn (II) and Mn (III) species was discussed. Three degradation pathways of BPAF were determined by the GC/MS and LC/MS technology, including chemical mechanism of oxidation, hydroxylation, electron transfer, polymerization, and ring-cleavage. In addition, the results suggested that the Mn3O4/PMS system had an efficient total organic carbon (TOC) removal rate and excellent environmental adaptability, the removal rate of TOC being as high as 73.2% in the control condition. Furthermore, the reuse experiments and the comparison on the structural and componential changes of Mn3O4 powder before and after reaction demonstrated that the Mn3O4 catalyst possessed excellent stability and reusability. Finally, a maximum BPAF degradation of approximately 90.0% was achieved on the optimal conditions for 500 mg/L Mn3O4 dosage, 4 mM PMS concentration, 7.0 ± 0.2 initial pH, and 5 mg/L BPAF concentration respectively. And the effect of the coexisting anions and natural environmental water quality were also considered. This study demonstrated the Mn3O4/PMS system can be considered as a green approach for the removal of environmental reluctant pollutants.

Dual-iodine-doped BiOIO3: Bulk and surface co–modification for enhanced visible-light photocatalytic removal of bisphenol AF

Developing effective and feasible treatment methods to address high-risk emerging contaminants is a tremendous and persistent challenge to environmental safety. Bisphenol AF (BPAF), one of the most often used bisphenol A (BPA) alternatives, has a higher lethality, estrogenic activity, and developmental toxicity than BPA, and is difficult to decompose, yet studies to remove BPAF are very limited. Herein, by analysis and design of band structure, single bulk-doped, single surface-doped, and bulk and surface dual-iodine-doped BiOIO3 photocatalysts are fabricated via modifying pristine BiOIO3 using ion exchange or/and in situ reduction strategies. The respective role and synergistic effect of iodine doping at different locations of BiOIO3 are then discussed. As dual doping mode affords a high iodine content, rich oxygen vacancies, and more dispersed band structure, the as-synthesized dual-iodine-doped BiOIO3 exhibits strong visible-light absorption (from UV to ~ 750 nm), strong oxidation ability (valence band potential of 2.68 V), and efficient charge separation kinetics, resulting in an excellent visible-light photocatalytic activity for BPAF degradation. After 2 h of photoreaction, the degradation percentage and TOC reduction of BPAF reach 96.5% and 94.0%, respectively, which far exceed those of BiOIO3, BiOI, or single iodine-doped BiOIO3. The radical trapping experiments and EPR analysis reveal that h+, e−, O2−, OH, and 1O2 are all involved in the catalytic process. The reaction intermediates are identified, and a reasonable photocatalytic mechanism is proposed. In addition, the synthetic dual-iodine-doped photocatalyst maintains stability during photoreaction and is successfully applied to a real wastewater sample, demonstrating its potential in practical applications.

Crucial roles of oxygen and superoxide radical in bisulfite-activated persulfate oxidation of bisphenol AF: Mechanisms, kinetics and DFT studies

Though natural reducing agents have been demonstrated as desirable catalysts for environmental remediation, the mechanism of catalytic activation of persulfate (PS) by bisulfite (S(IV)) remains unclear. In this study, an emerging contaminant bisphenol AF (BPAF) was employed as the target compound to examine the activation and degradation mechanism in PS/S(IV) system. Sulfate radical (SO4•–) was evidenced as the dominant radical accounting for BPAF degradation via quantitative analysis, while hydroxyl radical (•OH) and singlet oxygen (1O2) were minor contributors. Superoxide radical (O2•–) was identified as an intermediate radical in promoting BPAF removal through quenching experiments and electron paramagnetic resonance analysis. Tests in oxygen-rich and oxygen-deficient systems were conducted and the results were contrasted to elucidate the important role of oxygen in BPAF degradation and SO4•–-formation. In addition, the effect of Dissolved Oxygen (DO) was simulated using two separate kinetic models. Decomposition mechanism of BPAF was afterwards clarified via the density-functional theory calculations using Fukui index to predict the vulnerable sites and the intermediate products. This study provides a mechanistic understanding of the activation of PS/S(IV) system on the BPAF removal, especially the critical role of DO and O2•– in SO4•– generation.

Enhanced Transformation of Emerging Contaminants by Permanganate in the Presence of Redox Mediators.

In this study, a permanganate/redox mediator system for enhanced transformation of a series of emerging contaminants was evaluated. The presence of various redox mediators (i.e., 1-hydroxybenzotriazole, N-hydroxyphthalimide, violuric acid, syringaldehyde, vanillin, 4-hydroxycoumarin, and p-coumaric acid) accelerated the degradation of bisphenol A (BPA) by Mn(VII). Since 1-hydroxybenzotriazole (HBT) exhibited the highest reactive ability, it was selected to further investigate the reaction mechanisms and quantify the effects of important reaction parameters on Mn(VII)/redox-mediator reactions with BPA and bisphenol AF (BPAF). Interestingly, not only HBT accelerated the degradation of BPA, but also BPA enhanced the decay of HBT. Evidence for the in situ formation of HBT· radicals as the active oxidant responsible for accelerated BPA and BPAF degradation was obtained by radical scavenging experiments and 31P NMR spin trapping techniques. The routes for HBT· radical formation involving Mn(VII) and the electron-transfer pathway from BPA/BPAF to HBT· radicals demonstrate that the Mn(VII)/HBT system was driven by the electron-transfer mechanism. Compared to Mn(VII) alone, the presence of HBT totally inhibited self-coupling of BPA and BPAF and promoted β-scission, hydroxylation, ring opening, and decarboxylation reactions. Moreover, Mn(VII)/HBT is also effective in real waters with the order of river water > wastewater treatment plant (WWTP) effluent > deionized water.

Peroxymonosulfate activation by porous BiFeO3 for the degradation of bisphenol AF: Non-radical and radical mechanism

In this study, porous BiFeO3 (BFO) was successfully synthesized by sol-gel method and employed as an activator for peroxymonosulfate (PMS) to degrade bisphenol AF (BPAF), an emerging contaminant in the water. Porous BFO were prepared and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and oxygen temperature programmed desorption (O2-TPD). Compared to the raw BFO, large improvement of BPAF removal was observed when using porous BFO to activate PMS. The influences of selected activating systems, PMS dosage, catalysts loading, initial pH and water matrix on the degradation efficiency were examined. The role of reactive oxygen species produced in the degradation process of BPAF were identified through chemical quenching experiments and electron spin resonance (ESR), which demonstrated that high performance of porous BFO/PMS on BPAF removal was ascribed to the co-oxidation of radicals (sulfate radical and hydroxyl radical) and non-radical reactive oxygen species (singlet oxygen). Based on the XPS and ESR results, this study proved that lattice oxygen on the surface of BFO participated in the formation of singlet oxygen and the oxygen vacancies were propitious for the catalytic degradation. The reaction pathways and the mechanism of BPAF degradation via the BFO/PMS system were also proposed.

Ultrasound-enhanced zero-valent copper activation of persulfate for the degradation of bisphenol AF

Ultrasound (US) was introduced into a persulfate (PS)/zero-valent copper (ZVC) system for the degradation of bisphenol AF (BPAF). In this system, ZVC worked as a catalyst to activate PS. Compared with the PS/ZVC process, the degradation rate of BPAF in the PS/ZVC/US system raised significantly from 59.8% to 97.0% due to a synergistic interaction between sonolysis and a heterogeneous reaction. When ultrasound was 120 W at 20 kHz and initial BPAF concentration was 20 μmol/L, the BPAF could be completely removed after a 60-min reaction with 0.5 g/L ZVC, 1 mM PS. According to kinetics research, the decomposition of BPAF in a PS/ZVC/US system could be separated into two stages with a demarcation point after about 20 min of reaction via pseudo-first-order rate constants (kobs). A Quantitative analytical modeling for the study of main radicals was established, and the result indicated SO4∙- was the predominant radical in acidic conditions and both ·OH and SO4∙- were the predominant radicals in relative basic conditions. Moreover, the effects of initial persulfate dosage, initial BPAF concentration, and coexisting inorganic anions on BPAF degradation were evaluated. A high-accuracy mass spectrometer was used to study the oxidation process and potential activities were deduced. Finally, the possible reaction mechanisms in the PS/ZVC/US system is proposed that the surface heterogeneous catalysis was the key step to activate PS. This work will promote the understanding of the utilization of ZVC in advanced oxidation and also the key role of Cu+ in activating PS.

Aerobic Soil Biodegradation of Bisphenol (BPA) Alternatives Bisphenol S and Bisphenol AF Compared to BPA.

Pressures to ban bisphenol A (BPA) has led to the use of alternate chemicals such as BPA analogues bisphenol S (BPS) and bisphenol AF (BPAF) in production of consumer products; however, information on their environmental fate is scarce. In this study, aerobic degradation of BPA, BPAF, and BPS at 100 μg/kg soil and 22 ± 2 °C was monitored for up to 180 days in a forest soil and an organic farm soil. At each sampling point, soils were extracted three times and analyzed by liquid chromatography high resolution mass or time-of-flight mass spectrometry. Based on compound mass recovered from soils compared to the mass applied, BPS had short half-lives of <1 day in both soils similar to BPA. BPAF was much more persistent with observed half-lives of 32.6 and 24.5 days in forest and farm soils, respectively. To our knowledge, this is the first report on BPAF degradation. For all three compounds, half-lives were longer in the higher organic carbon (OC) forest soil which correlates well to sorption studies showing higher sorption with higher OC. Metabolites identified for all three bisphenols support degradation pathways that include meta-cleavage as well as ortho-cleavage, which has not been previously shown.