Degradation Of Emerging Contaminants Research Articles

Remediation of imidacloprid and carbamazepine in polluted soil using TiO2 with LED lamps

Imidacloprid and carbamazepine are recognised as emerging contaminants (ECs) due to their ubiquitous presence in environmental compartments and their potential to cause undesirable ecological effects. Wastewater treatment plants are relevant routes for these compounds to enter environment since they are continuously released through treated wastewater. The progressively more extended custom of reusing treated wastewater for agricultural irrigation has also enlarged the risks for ECs accumulation in soil and their translocation to crops, posing a constant threat to both humans and wildlife. This work is aimed to study the behaviour of imidacloprid and carbamazepine and its main transformation products generated in soil during photocatalytic treatments using commercial TiO2 (Degussa P25) and ultraviolet light emitting diode (UV-LED) lamps as light source. Prior to remediation trial, the influence of catalyst load and soil moisture content in ECs degradation was studied. Experiments were performed using a photochemical reactor equipped with LED lamps running at 365 nm, exposing polluted soils to different treatments in presence and absence of photocatalyst. A significant degradation (93.4 and 96.2% for imidacloprid and carbamazepine, respectively) was observed after 4 days of photocatalytic treatment. The main transformation products were identified during the different treatments. Our results suggest that TiO2-photocatalytic treatment combined with UV-LED could be considered a promising technology to remove ECs from soils.

Critical perspective on the elimination of emerging contaminants from industrial wastewater via microbial electrochemical technologies

AbstractIndustrial water pollution originating from various industries like textile, dairy, oil, and petrochemical industries, etc. is a huge concern globally and has led to devastating effects on the environment due to the release of refractory emerging contaminants (ECs). These ECs of concern have attracted wide devotion from the scientific community due to their recalcitrant nature and disastrous effects on plants, aquatic life forms, and humans. In this regard, conventional wastewater treatment technologies such as coagulation, flocculation, membrane technologies, electrocoagulation, and other biological technologies like sequencing batch reactor, anaerobic up‐flow sludge blanket reactor, etc., are inefficient in removing ECs from the industrial effluent, while conventional advanced oxidation processes incur high cost due to the extensive requirement of energy for the degradation of ECs. To overcome this issue, microbial electrochemical technologies (METs) can be employed. For instance, METs have shown promising results in the degradation of various ECs, such as microbial fuel cells, which have shown nearly 92% to 98% removal of sulfamethoxazole with simultaneous power recovery. Alizarin yellow R, nitrobenzene, and Congo red were degraded by microbial electrolysis cells with removal efficiency in the range of 88% to 98%, demonstrating their superiority in the elimination of trace contaminants. Similarly, almost 100% mineralization of pyraclostrobin was noticed for the bio‐electro‐Fenton process, showing the elevated potential of these neoteric technologies for the remediation of recalcitrant pollutants. Thus, the current review article aims to critically analyze the intervention of METs for the elimination of ECs from industrial wastewater.

Sulfite activation by ultrasound for the degradation of emerging contaminants: The dependence of pollutant property and mechanistic study

The easy recombination of •OH radicals in ultrasonic processes (US) always leads to the inadequacy in degrading relatively hydrophilic pollutants. Herein, sulfite was activated by ultrasound and the US/S(IV) process was for the first time applied to degrade emerging contaminants (ECs) with different physicochemical properties. Kinetic analysis and density functional theory (DFT) calculation showed that LogP of ECs was the dominant factor affecting the degradation efficiency in both US and US/S(IV) processes, and the addition of S(IV) more significantly improved the degradation of compounds with low LogP, high EHOMO and low ΔE (ΔE = ELUMO – EHOMO). The main mechanism of sulfite activation was attributed to •OH rather than the heat. The recombination of •OH could be well inhibited by sulfite and more •OH and SO4•− radicals could be derived from SO3•− in the bulk phase with the presence of O2. Based on DFT and LC/MS analysis, the reactive sites of sulfamethoxazole (SMX) upon the attack from •OH and SO4•− were identified and three degradation pathways were proposed. The primary intermediates of SMX could be efficiently degraded into smaller compounds in US/S(IV) process. Moreover, US/S(IV) process showed stronger adaptability to a broad pH range and complex water matrix than US process. This work may provide new insights into the sulfite activation technologies and a promising alternative for efficient degradation of ECs with different physicochemical properties.

Kraft lignin-derived multi-porous carbon toward sustainable electro-Fenton treatment of emerging contaminants

Reclaiming biomass waste to carbon cathode is promising to construct a sustainable electrochemical system. Here, we developed a novel thermal foaming process to reform kraft lignin to a free-standing and multi-porous carbon foam, which can be used as carbon cathode for electro-Fenton treatment of emerging contaminants (ECs). Benefiting from the excellent physicochemical and electrochemical properties with multi-porous and graphitic structure, the synthesized carbon foam cathode enhanced the electrocatalytic generation of H2O2 and •OH, and subsequently promoted the mass transfer and interactions among reactants (i.e., O2, H2O2, Fe2+, •OH, natural organic matters, and ECs). Eventually, an efficient degradation of ECs was achieved most likely via the multi-step •OH addition, cleavage, and ring opening reactions. Overall, the outcomes of this work provide a sustainable and applicable design and strategy to upgrade lignin-containing biomass to carbon cathode for efficient ECs remediation.

Recent Advances in Black Phosphorous-Based Photocatalysts for Degradation of Emerging Contaminants.

The recalcitrant nature of emerging contaminants (ECs) in aquatic environments necessitates the development of effective strategies for their remediation, given the considerable impacts they pose on both human health and the delicate balance of the ecosystem. Semiconductor-based photocatalytic technology is recognized for its dual benefits in effectively addressing both ECs and energy-related challenges simultaneously. Among the plethora of photocatalysts, black phosphorus (BP) stands as a promising nonmetallic candidate, offering a host of advantages including its tunable direct band gap, broad-spectrum light absorption capabilities, and exceptional charge mobility. Nevertheless, pristine BP frequently underperforms, primarily due to issues related to its limited ambient stability and the rapid recombination of photogenerated electron-hole pairs. To overcome these challenges, substantial research efforts have been devoted to the creation of BP-based photocatalysts in recent years. However, there is a noticeable absence of reviews regarding the advancement of BP-based materials for the degradation of ECs in aqueous solutions. Therefore, to fill this gap, a comprehensive review is undertaken. In this review, we first present an in-depth examination of the fabrication processes for bulk BP and BP nanosheets (BPNS). The review conducts a thorough analysis and comparison of the merits and limitations inherent in each method, thereby delineating the most auspicious avenues for future research. Then, in line with the pathways followed by photogenerated electron-hole pairs at the interface, BP-based photocatalysts are systematically categorized into heterojunctions (Type I, Type II, Z-scheme, and S-scheme) and hybrids, and their photocatalytic performances against various ECs and the corresponding degradation mechanisms are comprehensively summarized. Finally, this review presents personal insights into the prospective avenues for advancing the field of BP-based photocatalysts for ECs remediation.

Preparation of MgIn2S4/g-C3N4 for enhanced ranitidine photocatalytic degradation activity via Z-scheme electron transfer

The evidence so far indicates that ranitidine (RAN) contains N-nitrosodimethylamine (NDMA), a strong carcinogen, which is extremely harmful to human health under long-term exposure. Hence, a well-design Z-scheme heterostructure composed of 3D MgIn2S4 micro-flower and 2D g-C3N4 nanosheets was fabricated and used to remove RAN. The optimal photocatalyst (MG-30) exhibited the fastest RAN degradation rate of 0.24685 min−1 within 30 min under visible light, which was 78.1 and 19.8 times higher than those of bare MgIn2S4 and g-C3N4, respectively. Impressively, MG-30 was exceedingly resistant to environmental variations including organic matter, inorganic salts and aqueous substrates. In the meantime, MG-30 boasted the merit such as wide pH range for RAN removal. The excellent results originated from the construction of Z-scheme heterojunctions, which improved the carrier separation efficiency and retained the strong redox ability of MG-30, thereby contributing to the creation of rich active species. Meanwhile, the 3D/2D structure of MgIn2S4/g-C3N4 overrode the limited reflection of visible light. The active species analyses revealed that superoxide radical (·O2−) and hydroxyl radical (·OH) mainly participated in RAN degradation. Furthermore, the possible degradation pathways of RAN and toxicity analysis of intermediates produced were presented. This work emphasizes practical application potential of Z-scheme heterostructure photocatalysts for emerging contaminants degradation in wastewater.

Selective formation of high-valent iron in Fenton-like system for emerging contaminants degradation under near-neutral and high-salt conditions

In view of the near-neutral and high-salt conditions, the Fenton technology with hydroxyl radicals (HO•) as the main reactive species is difficult to satisfy the removal of trace emerging contaminants (ECs) in pharmaceutical sewage. Here, a layered double hydroxide FeZn-LDH was prepared, and the selective formation of ≡Fe(IV)=O in Fenton-like system was accomplished by the chemical environment regulation of the iron sites and the pH control of the microregion. The introduced zinc can increase the length of Fe-O bond in the FeZn-LDH shell layer by 0.22 Å compared to that in Fe2O3, which was conducive to the oxygen transfer process between ≡Fe(III) and H2O2, resulting in the ≡Fe(IV)=O formation. Besides, the amphoteric hydroxide Zn(OH)2 can regulate the pH of the FeZn-LDH surface microregion, maintaining reaction pH at around 6.5–7.5, which could avoid the quenching of ≡Fe(IV)=O by H+. On the other hand, owing to the anti-interference of ≡Fe(IV)=O and the near-zero Zeta potential on the FeZn-LDH surface, the trace ECs can also be effectively degraded under high-salt conditions. Consequently, the process of ≡Fe(IV)=O generation in FeZn-LDH system can satisfy the efficient removal of ECs under near-neutral and high-salt conditions.

Highlight the plasma-generated reactive oxygen species（ROSs）dominant to degradation of emerging contaminants based on experiment and density functional theory

This paper aims to deeply analyze the degradation mechanism of emerging contaminants by dielectric barrier discharge (DBD) plasma through experiments and simulations. It was confirmed that DBD plasma exhibits a high degradation effect on three emerging contaminants by the generated reactive oxygen species (ROSs). Increasing the output power leads to higher ROSs production and higher degradation rates of emerging contaminants. At an input power of 94.6 W, the degradation rates of sulfamethoxazole (SMX), bisphenol A (BPA) and ciprofloxacin (CIP) reach 94.5 %, 92.9 %, and 98.6 %, respectively. Trapping agent experiments were conducted to investigate the role of ROSs (·OH, ·O2–, and 1O2) in emerging contaminants degradation. Notably, capturing of 1O2 led to a decrease of up to 31 % in the degradation rate of BPA. Electron spin resonance (ESR) tests confirmed the involvement of various ROSs, especially 1O2, in the degradation process. Density functional theory (DFT) was employed to further explore the action mechanism of ROSs in the DBD plasma system. For SMX and BPA, the degradation is initiated by the dissociation of annular structures, while for CIP, annular structures are directly opened by ROSs. These findings highlight the importance of 1O2 and ·OH in the degradation process. Finally, the toxicity of intermediates produced by ROSs-dominate to degradation was declined. This work can provide new insights and unique guidance on the plasma degradation mechanism of emerging contaminants.

Composting post-anaerobic digestion for emerging contaminant biodegradation: Impacts of operating conditions.

Sustainable manure management technologies are needed, and combining anaerobic digestion (AD) for energy generation and aerobic composting (AC) to stabilize digestate and remove emerging contaminants (ECs), including veterinary pharmaceuticals and steroid hormones, is promising. This study identified post-AD, AC operating conditions that maximized degradation of study ECs, expected to be present in cattle manure digested using treated municipal wastewater as the water source. Study ECs included sulfamethoxazole (SMX), chlortetracycline (CTC), oxytetracycline (OTC), estrone (E1), and naproxen (NPX). Composting conditions were simulated in bench-scale reactors, with microorganisms from digestate produced in an AD system (25L scale), by varying temperatures, pH, and carbon source compositions (representing food waste/manure co-digestion with different residence times). Results indicate maximum SMX biodegradation occurred at 35°C, pH 7, and with high levels of easily degradable carbon (≥99%, 99%, and 98%), and maximum E1 biodegradation occurred at 35°C, and with low levels of easily degradable carbon (≥97% and 99%). Abiotic degradation was responsible for the nearly complete removal of tetracyclines under all conditions and for partial degradation of NPX (between 20% and 48%). Microorganisms originating from the AD system putatively capable of SMX and E1 biodegradation, or of contributing to biodegradation during the AC phase, were identified, including phylotypes previously shown to biodegrade SMX (Brevundimonas and Alcaligenes).

ZnAl/ZnSn(OH) composite photocatalyst for emerging contaminants degradation in water

Layered double hydroxides (LDH) are a versatile group of lamellar inorganic solids with a brucite-like structure similar to hydrotalcite that has undergone multiple improvements to be applied in various fields such as carbon dioxide sequestration, catalysis, drug delivery, energy conversion, and storage, as well as environmental remediation. It is then that this material becomes interesting for its application in water treatment since it has various practical features, e.g. tunable structure, excellent thermal stability, memory effect, high specific surface, high dispersion and regenerative viability. By taking advantage of this versatility, in this research work, the synthesis and characterization of ZnAl hydrotalcite modified with Sn through the coprecipitation method is reported. The presence of hydrotalcite ZnAl, and Zinc hydroxystannate phases were observed in the X-ray diffraction spectra. In the same way, it was possible to observe through the SEM micrographs the morphology associated with the union of both phases; i.e. lamellar and microcubic. In the bandgap energy measurement, the shift of the hydrotalcite value is observed as well as the appearance of another signal of zinc hydroxystannate species. The obtained materials were evaluated for the photocatalytic degradation of acetaminophen to 20 ppm under UV light. ZnAl/ZnSn(OH)6 composite showed better efficiency in the paracetamol degradation under UV light. Additionally, studies of the variation of ZnAl/ZnSn(OH)6 ratio and pH values of the solution were carried out, achieving photodegradation efficiency > 95 %, after 60 min of irradiation, using 0.15 g of ZnAl/ZnSn(OH)6 photocatalyst at pH= 6. The reusability was evaluated by testing the material in photodegradation cycles.

New insights into degradation of emerging contaminants by S(IV)/Fe(VI) system in neutral water: Performance enhancement, reaction mechanisms and toxicity assessment

This study proposes a novel approach to enhance the degradation of emerging contaminants (ECs) in neutral water using the S(IV)/Fe(VI) system and identifies the significant role of high-valent iron (Fe(V)/Fe(IV)) in selective oxidation. In the complex of bisulfite and sulfite (B1S3)/Fe(VI) system, the degradation rates and pseudo-first-order rate constants of sulfamethoxazole (SMX), carbamazepine (CBZ), 2,4-dihydroxybenzophenone (BP-1) and 4,4′-sulfonyldiphenol (BPS) were higher than those achieved with single S(IV) activation Fe(VI). The results were attributed to the dominance of Fe(V)/Fe(IV) in the selective oxidations which involved the participation of HO• and SO4•−. In addition, the degradation mechanisms of SMX, CBZ, BP-1, and BPS were proposed, and the acute toxicity, chronic toxicity, developmental toxicity, and bioaccumulation factors of the transformation products were assessed. The results showed that the removal of ECs by the B1S3/Fe(VI) system resulted in a reduction in toxicity. The effects of experimental conditions and water matrix on the removal of ECs were evaluated and achieved satisfactory results in three different real water samples. The B1S3/Fe(VI) system was capable of rapid degradation of ECs at relatively low S(IV) and Fe(VI) doses, and the ultimate products (SO42− and Fe(III)) promoted coagulation, indicating multiple application scenarios and tremendous engineering potential.

Ferrous ion enhanced Fenton-like degradation of emerging contaminants by sulfidated nanosized zero-valent iron with pH insensitivity

In this study, the performance and mechanism of the integrated sulfidated nanosized zero-valent iron and ferrous ions (S-nZVI/Fe2+) system for oxygen activation to remove emerging contaminants (ECs) were comprehensively explored. The S-nZVI/Fe2+ system exhibited a 2.4–8.2 times of increase in the pseudo-first order kinetic rate constant for the oxidative degradation of various ECs compared to the S-nZVI system under aerobic conditions, whereas negligible removal was observed in both nZVI and nZVI/Fe2+ systems. Moreover, remarkable EC mineralization efficiency and benign detoxification capacity were also demonstrated in the S-nZVI/Fe2+ system. We revealed that dosing Fe2+ promoted the corrosion of S-nZVI by maintaining an acidic solution pH, which was conducive to O2 activation by dissolved Fe2+ and surface-absorbed Fe(II) to produce •OH. Furthermore, the generation of H* was enhanced for the further reduction of Fe(III) and H2O2 to Fe(II) and •O2–, resulting in the improvement of consecutive single-electron O2 activation for •OH production. Additionally, bisphenol A (BPA) degradation by S-nZVI/Fe2+ was positively correlated with the S-nZVI dosage, with an optimum S/Fe molar ratio of 0.15. The Fenton-like degradation process by S-nZVI/Fe2+ was pH-insensitive, indicating its robust performance over a wide pH range. This study provides valuable insights for the practical implementation of nZVI-based technology in achieving high-efficiency removal of ECs from water.

Construction of cubic CaTiO3 perovskite modified by highly-dispersed cobalt for efficient catalytic degradation of psychoactive pharmaceuticals

Sulfate radical mediated advanced oxidation processes (SR-AOPs) have emerged as a promising alternative for emerging contaminants degradation. However, high activity and great stability are commonly difficult to juggle, and the structure-activity correlations are still ambiguous. This study constructed the cubic CaTiO3 perovskite modified by highly-dispersed cobalt for peroxymonosulfate (PMS) activation to improve the specific lattice plane exposure and reduce the metal leaching simultaneously. 98% of amitriptyline (AMT) degradation was achieved within 60 min under the condition of 200 mg/L Co0.1-CTO and 100 mg/L PMS. The results indicated that surface Co2+/Co3+ redox couple and lattice oxygen were responsible for PMS activation, and the evolution of ·OH, SO4·- and 1O2 were revealed. According to density functional theory (DFT) calculations, the highly-dispersed Co on cubic surface effectively captured PMS and promoted electron transfer for the generation of ·OH and SO4·-, while more oxygen atoms exposed on Co0.1-CTO(200) surface facilitated the generation of 1O2. Briefly, this study provides a novel strategy of catalyst synthesis in PMS activation for water treatment.

Highly efficient activation of sulfite by p-type S-doped g-C3N4 under visible light for emerging contaminants degradation

The photocatalytic activation of sulfite is a one-electron oxidation process of SO32− or HSO3−, and therefore the property of photo-generated holes is essential in determining the activation performance. The n-type g-C3N4 (pCN) was successfully converted to p-type by substituting N2C positions by S (SCN), which not only increased the hole density but also positively shifted the valence band (VB). Whereafter, the SCNs were for the first time applied in sulfite activation under visible light irradiation to degrade diclofenac (DCF). The 1:1SCN showed the highest VB potential of 2.45 V, which exhibited the best performance in activating S(IV). Moreover, the 1:1SCN also demonstrated improved photoelectric properties and enhanced adaptability to complex water qualities (pH, different emerging contaminants, high pollutant concentration and water matrices). The density functional theory (DFT) calculations implied that the doping of S improved the sulfite adsorption capability of 1:1SCN, favorably producing SO3•− as the primary active species. Diverse reactive oxidation species including h+, •OH, SO3•− and SO5•− were present, and h+ and SO5•− were identified as the dominant contributors to DCF degradation. Based on DFT calculations and LC/MS analysis, four pathways were proposed for DCF degradation. This work provides new insights into the sulfite activation technologies and a promising alternative for efficient degradation of emerging contaminants in water.

Activation of peroxymonosulfate by cow manure biochar@1T-MoS2 for enhancing degradation of dimethyl phthalate: Performance and mechanism

Introduction: Dimethyl phthalate (DMP) which has been widely detected in water is neurotoxic to humans and should be effectively eliminated. Persulfate-based advanced oxidation processes are considered to be reliable methods aiming at emerging contaminants degradation, while an efficient catalyst is urgently needed for the activation of the reaction. As a typical 2D material, 1T-MoS2 is expected to be applied to the activation of persulfate owing to its abundant active sites and excellent electrical conductivity. In practical applications, 1T-MoS2 has the phenomenon of reunion which affects the exposure of its catalytic sites.Methods: Therefore, in this study, we used waste cow manure as a raw material to prepare biochar and achieved high exposure of 1T-MoS2 activation sites by loading 1T-MoS2 onto the surface of cow manure biochar through hydrothermal synthesis. The prepared composite catalytic material CMB@1T-MoS2 was used to activate PMS for the degradation of DMP.Results: It was found that CMB@1T-MoS2 has better effect than CMB or 1T-MoS2 alone for the degradation of DMP, reaching 77.65% at pH = 3. Under alkaline conditions, the degradation rate of DMP was reduced due to the inhibition of the catalytic process. Among the different coexisting anions, HCO-3 interfered and inhibited the degradation process the most, leading to the lowest degradation rate of DMP with 42.45%.Discussion: The quenching experiments and EPR analysis showed that SO-4• and •OH were the main ROS in the CMB@1T-MoS2/PMS process. This study promotes the resourceful use of cow manure and is expected to provide a novel persulfate-based advanced oxidation process catalyzed by CMB@1T-MoS2 for the elimination of DMP in an aqueous environment.

Resourcelized conversion of livestock manure to porous cage microsphere for eliminating emerging contaminants under peroxymonosulfate trigger.

Pollution and resource waste caused by the improper disposal of livestock manure, and the threat from the release of emerging contaminants (ECs), are global challenges. Herein, we address the both problems simultaneously by the resourcelized conversion of chicken manure into porous Co@CM cage microspheres (CCM-CMSs) for ECs degradation through the graphitization process and Co-doping modification step. CCM-CMSs exhibit excellent performance for ECs degradation and actual wastewater purification under peroxymonosulfate (PMS) initiation, and show adaptability to complex water environments. The ultra-high activity can maintain after continuous operation over 2160 cycles. The formation of C-O-Co bond bridge structure on the catalyst surface caused an unbalanced electron distribution, which allows PMS to trigger the sustainable electron donation of ECs and electron gain of dissolved oxygen processes, becoming the key to the excellent performance of CCM-CMSs. This process significantly reduces the resource and energy consumption of the catalyst throughout the life cycle of production and application.

Recent Advancements in the Treatment of Emerging Contaminants Using Activated Persulfate Oxidation Process

Emerging contaminants (ECs) usually refer to pesticides, polycyclic aromatic hydrocarbons (PAHs), dioxins, personal care products, cosmetics, and medications. Due to the strong demand and quick growth of these businesses, the ECs have continuously been found in alarming amounts in groundwater, surface water, and wastewater. These ECs provide a significant non-esthetic threat to the ecosystem as a whole and can cause significant non-esthetic contamination when released into the aquatic environment. The conventional wastewater treatment techniques such as activated sludge, membrane filtration, coagulation, adsorption, and ozonation showed ECs removal performance to a certain extent. In turn, numerous emerging advanced oxidation processes (AOPs), especially activated persulfate oxidation, have garnered a huge amount attention due to their outstanding performance in the remediation of ECs. This article presents a systematic and critical review of electro, sono and thermal activation of persulfate for the treatment of ECs. The effect of key parameters such as electrode materials, solution pH, persulfate concentration, current density, and temperature on electro, sono- and thermal-activated degradation of ECs was discussed. The possible reaction mechanism of ECs degradation was also elucidated in detail. It was closed with a note on the situation now and the future course of electro, sono and thermal activation in ECs degradation applications. Experiments performed in recent studies show that with the aid of persulfate in electro activation, the removal efficiency of chemical oxygen demand can be achieved up to 72.8%. Persulfate activated by sono shows 100% removal efficiency of 1,1,1-trichloroethane and sulfamethoxazole. While for thermal activation of persulfate, 100% removal efficiency of carbamazepine, atrazine and sulfamethazine was achieved. All these vital shreds of evidence are substantial enough to picture the negative impact of ECs on the environment.

Exploring degradation properties and mechanisms of emerging contaminants via enhanced directional electron transfer by polarized electric fields regulation in Fe-N4-Cx

Heterogeneous catalysis offers an opportunity to overcome the low efficiency and secondary pollution limitations of emerging contaminants (ECs) purification technologies, but it is still challenging to regulate electron directed transport for achieving high catalysis efficiency and selectivity due to insufficient understanding of the electron transfer pathways and behavioral mechanisms during its catalysis. Here, by tuning the defects of the C-N coordination of the support, the polarized electric field (PEF) characteristics are changed, which in turn affects the electron transport behavior. The results show that the charge offset on Fe-N4-Cx forms a PEF, which will induce directional electron transport. After the quantitative structure-activity relationship (QSAR) fitting analysis, the greater the degree of C-N defects, the higher the intensity of the PEF, which in turn enhances the electron transport and promotes the catalytic behavior. In addition, the surface pyrrole N site can adsorb enrofloxacin (ENR) and enrich it on the surface. This can reduce the transport distance of reactive oxygen species (ROS) to synergize catalysis and adsorption, resulting in rapid degradation of ECs. Combined with liquid chromatograph mass spectrometer (LC-MS) results and theoretical calculations, five degradation pathways of ENR were speculated, mainly including the oxidation of piperazine and the cleavage of the quinolone ring. This work proposes a novel PEF regulation strategy and explores its mechanism for safe treatment of ECs.

Catalytic Decomposition of Peroxymonosulfate Using Biochar for Emerging Contaminants Degradation

Catalytic Decomposition of Peroxymonosulfate Using Biochar for Emerging Contaminants Degradation

Novel porous Mn-Fe nanocubes toward peroxymonosulfate activation via non-radical/radical pathways for emerging contaminants degradation

Novel porous Mn-Fe nanocubes (p-MnFe NCs) with abundant oxygen vacancies, which derived from Mn-Fe prussian blue analogue, were fabricated for the first time through annealing at H2 atmosphere. Among the different molar ratios of Mn/Fe, p-Mn1Fe1 NCs possessed abundant oxygen vacancies and exhibited excellent performance for peroxymonosulfate (PMS) activation to effectively degrade bisphenol A (BPA). As a result, 100% BPA (20 mg/L) degradation efficiency can be achieved within 30 min in the p-Mn1Fe1 NCs/PMS system. SO4•−, HO•, O2•− and 1O2 were confirmed as main reactive oxygen species during catalytic reaction. The exposed Mn and Fe sites on the surface of p-Mn1Fe1 NCs were the main active sites for the generation of reactive radicals. For non-radical generation pathway, the generated 1O2 and O2•− mainly originated from the reaction between dissolved oxygen and surface oxygen vacancies, and parts of 1O2 originated from the formation of intermediate O2•−. Radical and non-radical pathways were proposed in the p-Mn1Fe1 NCs/PMS system for insights into the mechanisms of BPA degradation. Finally, the possible degradation pathways were proposed via ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-TOF-Q-MS) analysis.