Enhanced Peroxymonosulfate Activation Research Articles

Enhanced Peroxymonosulfate activation via Bi 12 CoO 20 /rGO with Near‐Infrared Photothermal Response for Antibiotics Degradation

Against the backdrop of escalating antibiotic pollution, this study presents a novel approach to remediation using a photothermal heterogeneous Fenton‐like catalyst, Bi12CoO20/rGO, which efficiently activates peroxymonosulfate (PMS) under near‐infrared (NIR) light. This catalyst capitalize on the NIR absorption capabilities of Bi12CoO20 and the electron transfer properties of reduced graphene oxide (rGO). The restored sp2 structure of rGO serves as a conduit for electron transfer, crucial for the redox cycle of Co2+/Co3+ that facilitates PMS activation. Moreover, the incorporation of rGO significantly boosts the NIR absorption capacity of Bi12CoO20, thereby enhancing the photothermal conversion efficiency of the composite and further promoting PMS activation. This synergy enables efficient light‐to‐heat conversion and PMS activation, generating reactive oxygen species (ROS) essential for antibiotic degradation. Using levofloxacin (LVX) as a representative pollutant, the developed system achieves an impressive 99% degradation rate within just 30 min under Bi12CoO20/rGO + PMS + NIR conditions. Moreover, this approach demonstrates robust stability and adaptability across diverse water compositions and pH ranges. Its eco‐friendly nature and renewable characteristics position it as a promising solution for combating antibiotic pollution through photothermal Fenton‐like technology, thereby harnessing solar energy for environmental remediation and fostering sustainable water management practices.

Cerium oxide /Co-Co Prussian blue analogue composite catalyst for enhanced peroxymonosulfate activation for effective removal of tetracycline hydrochloride from water.

In this paper, a novel CeO2/Co3[Co(CN)6]2 (CeO2/PBACo-Co) composite was prepared with co-precipitation and utilized to activate peroxymonosulfate (PMS) to eliminate tetracycline hydrochloride (TCH). Catalyst screening showed that the composite with a CeO2:PBACo-Co mass ratio of 1:5 (namely, 0.2-CeO2/PBACo-Co) had the best performance. The degradation efficiency of TCH in 0.2-CeO2/PBACo-Co/Oxone system was investigated. The experimental results illustrated that 98% of 50 mg/L TCH and 48.5% of TOC were degraded by 50 mg/L 0.2-CeO2/PBACo-Co and 400 mg/L Oxone within 120 min at 25 °C and initial pH 5.3. Recycling studies showed that the elimination rate of TCH can still achieve 85.8% after five cycles, suggesting that 0.2-CeO2/PBACo-Co composite processes good reusability. Trapping experiments and EPR tests revealed that the reaction system produced multiple active species (1O2, O2•-, SO4•-, and •OH). We proposed the catalytic mechanism of 0.2-CeO2/PBACo-Co for PMS activation, which mainly involves the promoted Co3+/Co2+ cycle by Ce3+ donated electrons. These results indicate that CeO2/PBACo-Co composite is an effective catalyst for wastewater remediation.

Cellulose nanocrystals mediated spontaneous weaving of ZIF-67 hybrid networks: Enhanced peroxymonosulfate activation and rapid removal of dye

Inter-connected zeolite imidazolate framework-67 (ZIF-67) hybrid networks were successfully synthesized by a cellulose nanocrystals (CNCs) mediated spontaneous weaving strategy, which was denoted as ZIF-67@CNC, and was applied to activate peroxymonosulfate (PMS) for Rhodamine B (RhB) degradation. Characterizations results demonstrated that the ZIF-67 nanocrystals are encapsulated within CNCs and subsequently arranged in a string-like configuration. In comparison to pristine ZIF-67, the ZIF-67@CNC catalyst presented superior performances for RhB dye removal both in terms of degradation efficiency and rate, as the kinetic rate constant increased 5.8-fold. This finding was attributed to the improvement in oxygen-containing groups and meso/microporous structures after the introduction of CNCs, leading to efficient binding to compounds and rapid molecular diffusion. Moreover, the ZIF-67@CNC exhibited remarkable stability throughout the catalysis process in aqueous solutions owing to the robust crosslinking between negatively charged CNCs and positively charged cobalt ions, which significantly mitigated the potential secondary pollution of cobalt to the environment. This research opens up new possibilities for the design of highly efficient and durable ZIF-67-based catalysts to promote future wastewater treatment technology.

Enhanced PMS activation and NSAID degradation selectivity by hydrophobic microenvironment regulation on Fe3+@Cu-MOF

In this study, the activation of peroxymonosulfate (PMS) and selective degradation of nonsteroidal anti-inflammatory drugs were investigated using hydrophobically modified Fe3+@Cu-MOF. The Fe3+@Cu-MOF-CTAB/PMS system demonstrated high-efficiency, achieving near-complete degradation of diclofenac within 120min. The degradation rate constants for diclofenac, ibuprofen, and naproxen were 0.0048, 0.00103, and 0.00046min-1, respectively, positively correlated with their hydrophobicity. Longer hydrophobic surfactant chains in Fe3+@Cu-MOFs lead to greater initial adsorption of diclofenac, enhancing degradation efficiency upon the introduction of PMS. The Fe3+@Cu-MOF-CTAB/PMS system removes over 80% of diclofenac in various water matrices, showing optimal efficiency in acidic environments but reduced effectiveness with competing anions. Post-degradation changes in the oxidation states of copper and iron in the MOF structure indicated a synergistic redox mechanism essential for PMS activation. The hydroxylation and C-N bond cleavage in diclofenac were key degradation pathways. This study highlights the potential of hydrophobically modified Fe3+@Cu-MOFs in water treatment, providing insights into the interplay between material design, hydrophobic interactions, and catalytic performance.

Nitrogen-Doped Biochar for Enhanced Peroxymonosulfate Activation to Degrade Phenol through Both Free Radical and Direct Oxidation Based on Electron Transfer Pathways.

Nowadays, super nitrogen-doped biochar (SNBC) material has become one of the most promising metal-free catalysts for activating peroxymonosulfate (PMS) to degrade organic pollutants. To understand the evolution of SNBC properties with fabrication conditions, a variety of SNBC materials were prepared and characterized by elemental analysis, N2 adsorption-desorption, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. We systematically investigated the activation potential of these SNBC materials for PMS to degrade phenol. SN1BC-800 with the best catalytic performance was obtained by changing the activation temperatures and the ratio of biochar to melamine. The effects of catalyst dosage, the PMS concentration, pH, and reaction temperature on phenol degradation were studied in detail. In the presence of 0.3 g/L SN1BC-800 and 1 g/L PMS, the removal rate of 20 mg/L phenol could reach 100% within 5 min. According to electron paramagnetic resonance spectra and free radical quenching experiments, a nonfree radical pathway of phenol degradation dominated by 1O2 and electron transfer was proposed. More interestingly, the excellent catalytic performance of the SN1BC-800/PMS system is universally applicable in the degradation of other typical organic pollutants. In addition, the degradation rate of phenol is still over 80% after five reuses, which shows that the SN1BC-800 catalyst has high stability and good application prospects in environmental remediation.

Enhanced peroxymonosulfate activation for degradation of iodinated contrast media by microwave-induced bimetallic carbon-based catalysts: Insight into the synergistic mechanism between microwaves and bimetallic sites

Microwave-assisted catalytic oxidation process was a promising wastewater treatment technology for the disposal of refractory organic contaminants. Nevertheless, its practical implementation was limited by the high energy consumption of microwaves and the poor sustainable reactivity of catalysts. To address these issues, the microwave-assisted dielectric-activation double-responsive Co/Fe carbon-based catalyst (CoFe/NC-3) was used to activate peroxymonosulfate (PMS) for oxidative degradation of refractory diatrizoate (DTZ). The results showed that the DTZ was completely degraded within 6 min in the MW/CoFe/NC-3/PMS reaction system, and the degradation efficiency increased by 82.38% compared with the MW/Fe/NC/PMS system. It was attributed to the enriched active sites and prolonged redox cycling capability of the bimetallic catalysts. Moreover, microwave enhanced electron migration ability to accelerate the circulation of Fe3+/Fe2+/Fe0 and Co3+/Co2+ and generate more reactive oxygen species (ROSs) for the high-efficiency degradation of DTZ. The degradation pathways of DTZ were elucidated by LC-MS in combination with DFT calculation and the product toxicity was evaluated using ecological structure-activity relationship software (ECOSAR). The results showed that the majority of intermediate degradation products were not acute or chronic toxicity to fish, daphnia, and green algae. Overall, these results revealed that the MW/CoFe/NC-3/PMS system was a cost-effective and stable method for wastewater treatment.

Enhanced peroxymonosulfate activation by S-scheme AgI/Cu-BiVO4 heterojunction for efficient photocatalytic organics degradation and Microcystis aeruginosa inactivation: Performance, interfacial engineering and mechanism insight

Novel oxygen vacancies-enriched AgI/Cu-BiVO4 (ACBV) S-scheme heterojunction catalysts were constructed to boost photocatalytic organics degradation and M. aeruginosa inactivation with peroxymonosulfate (PMS) assistance. Specific interfacial charge transfer and abundant active centers were guided by introducing Cu doping and AgI coupling into BiVO4, with the catalytic activity and mechanism systematically investigated. The optimal 0.25-ACBV heterojunction exhibited 97.6% tetracycline (TC) degradation under PMS-assisted visible light and achieved effective inactivation of M. aeruginosa within 20 min (78.8%). The S-scheme heterostructure from Cu-BiVO4 to AgI and synergistic effects endowed the system with high-energy carrier transfer kinetics and strong oxygen reduction capability. Meanwhile, the redox cycling of Cu2+/Cu+ and surface oxygen defects served as electron acceptors to accelerate interfacial charge separation and as adsorption activation sites for PMS, promoting efficient mass transfer in the non-homogeneous system. This study inspires the design of high-performance S-scheme photocatalytic activators and expands their potential applications in environmental remediation.

Coordination environment engineering of MoS2-based nanocomposite by Ni atom incorporation for enhanced peroxymonosulfate activation

Ni-doped MoS2 can activate PMS effectively to degrade organic pollutants because the Ni doping can modulate the adsorption energy barrier of MoS2 to PMS molecule. However, how the coordination environment between Ni and MoS2 affects the activation of PMS to generate active species is poorly understood. In this paper, Ni substitutional or Ni adsorptive doping of MoS2 supported on TiO2/N-doped carbon nanofibers (designated as Nisub-MTC or Niads-MTC, respectively) were synthesized and used as PMS activators to degrade tetracycline (TC), respectively. In the case of Niads-MTC that the Ni atoms adsorb atop of S vacancies in MoS2, the reaction kinetic constant for TC degradation can reach 0.3381 min−1 within 10 min in Niads-MTC/PMS/Vis system. That is 1.84 times higher than that in Nisub-MTC/PMS/Vis system (0.1835 min−1), where the Mo sites in MoS2 are substituted with Ni atoms. This possibly due to that the Ni adsorptive doping can improve the regional activity of Mo-S bonds, which is more efficient than increasing the S vacancies by Ni substitutional doping. DFT calculations further support that the lower adsorption energy barriers of PMS were obtained on Ni adsorptive doping MoS2. Moreover, the main active species and possible TC degradation pathways were proposed. This work provides a new insight for designing metal doped heterogeneous catalysts with suitable coordination environments to improve PMS activation efficiency.

MOF derived highly dispersed bimetallic Fe-Ni nitrogen-doped carbon for enhanced peroxymonosulfate activation and tetracycline degradation

Transition metals as activators of peroxymonosulfate (PMS) are effective catalysts for the degradation of organic pollutants. The construction of multiple active sites is the key for enhanced PMS activation. Herein, we prepared ZIF-8 derived Fe- Ni nitrogen-carbon with highly dispersed bimetallic active sites, achieving a small amount of highly efficient catalytic performance for tetracycline (TC) degradation. The Fe and Ni elements in the catalyst were uniformly dispersed, resulting in a high specific surface area of 367 m2/g. Even at low metal concentrations (Fe=0.83%, Ni=0.33%), Fe-Ni-N-C/PMS showed superior performance in degrading total carbon TC. Its reaction rate constant was 1.71 times higher than Fe-N-C/PMS and 2.13 times higher than Ni-N-C/PMS. This significant improvement was attributed to the synergistic effect of the bimetallic components and the highly dispersed active sites. The mechanism was proposed that Fe-Ni-N-C activates PMS to generate hydroxyl radicals (•OH), sulfate radicals (SO4•−), superoxide radicals (O2•−), and singlet oxygen (1O2) to further degrade TC. Among them, 1O2 and SO4•−were the main reactive oxygen species. This work has provided a new insight into the development of transition metals with multiple active sites for the degradation of organic pollutants.

Directional charge transfer modulation in ultrathin polyporous carbon nitride nanotubes for enhanced peroxymonosulfate activation

Achieving enhanced degradation efficiency of the legacy pesticidal persistent organic pollutants in a photocatalysis coupling peroxymonosulfate activation (PC-PMS) system by boosting photogenerated carrier separation, remains considerable challenges. Herein, we delved into the directional charge transfer modulation of built-in electric field (BEF) within polyporous ultrathin carbon nitride nanotubes for strengthened PC-PMS mediated pesticide degradation. The ultrathin polyporous tubular nanostructure, are critical in shortening the diffusion pathways for the transport of photogenerated electron-hole pairs to the reaction interface, while simultaneously ensuring the abundant contact sites for the reaction medium. Additionally, the heptazine units containing amino groups served as oxidation centers under visible light, targeting the generation of reactive oxygen species of h+, O2•−, 1O2. While the heptazine units containing cyano groups and boron dopants acted as reduction centers, activating PMS and O2 to produce SO4•−, •OH and O2•−. The efficient generation of the radical species contributed to the ultrafast imidacloprid degradation in PC-PMS system. This study demonstrates that the combination of morphology and BEF engineering is a promising strategy for enhanced degradation efficiency of pesticide pollutants in the PC-PMS system.

Co single atom coupled oxygen vacancy on W18O49 nanowires surface to construct asymmetric active site enhanced peroxymonosulfate activation

Enhancing the activation of peroxymonosulfate (PMS) is essential for generating more reactive oxygen species in advanced oxidation process (AOPs). Nevertheless, improving PMS adsorption and expediting interfacial electron transfer to enhance reaction kinetics pose significant challenges. Herein, we construct confined W18O49 nanowires with asymmetric active centers containing Co-Vo-W (Vo: oxygen vacancy). The design incorporates surface-rich Vo and single-atom Co, and the resulting material is employed for PMS activation in water purification. By coupling unsaturated coordinated electrons in Vo with low-valence Co single atoms to construct an the “electron fountainhead”, the adsorption and activation of PMS are enhanced. This results in the generation of more active free radicals (SO4•-, •OH, •O2-) and non-free radicals (1O2) for the decomposition of micropollutants. Thereinto, the degradation rate of bisphenol A (BPA) by Co-W18O49 is 32.6 times faster that of W18O49 monomer, which is also much higher than those of other transition-metal-doped W18O49 composites. This work is expected to help to elucidate the rational design and efficient PMS activation of catalysts with asymmetric active centers.

Unveiling the oxidation mechanism of persistent organic contaminants via visible light-induced dye-sensitized reaction by red mud suspension with peroxymonosulfate

A dye-sensitized photocatalysis system was developed for degrading persistent organic contaminants using solid waste (i.e., red mud, RM) and peroxymonosulfate (PMS) under visible light. Complete degradation of acid orange 7 (AO7) was achieved in RM suspension with PMS, where the co-existence of amorphous FeO(OH)/α-Fe2O3 was the key factor for PMS activation. The experimental results obtained from photochemical and electrochemical observations confirmed the enhanced PMS activation due to the Fe-OH phase in RM. DFT calculations verified the acceleration of PMS activation due to the high adsorption energy of PMS on FeO(OH) and low energy barrier for generating reactive radicals. Compared to the control experiment without AO7 showing almost no degradation of other organic contaminants (phenol, bisphenol A, 4-chlorophenol, 4-nitrophenol, and benzoic acid), photo-sensitized AO7* enhanced electron transfer in the FeIII/FeII cycle, dramatically enhancing the degradation of organic contaminants via radical (•OH, SO4•−, and O2•−) and non-radical (dye*+ and 1O2) pathways. Therefore, the novel finding of this study can provide new insights for unique PMS activation by heterogeneous Fe(III) containing solid wastes and highlight the importance of sensitized dye on the interaction of PMS with Fe charge carrier for the photo-oxidation of organic contaminants under visible light.

Enhanced PMS activation by Mn2O3-loaded h-BN for levofloxacin removal: Unveiling the dominant influence of non-free radical pathway and N-Mn-mediated promotion of stable, long-lived Mn(IV) species

The Mn2O3-loaded hexagonal boron nitride (h-BN-Mn) catalyst for peroxymonosulfate (PMS) activation was successfully synthesized using a one-step calcination process. The h-BN-Mn/PMS system achieved an impressive 97 % levofloxacin removal within a mere 90-minute timeframe. This catalyst, h-BN-Mn, effectively addresses the challenge of elevated manganese leaching rates and exhibits a broad pH degradation spectrum spanning from 3 to 11. Notably, it maintained robust degradation performance over five cycles, showcasing the potential for large-capacity water treatment when integrated with a polyvinylidene fluoride (PVDF) membrane (h-BN-Mn@PVDF), resulting in an 83.8 % removal rate over 6 h. In-depth analysis revealed three distinct degradation pathways. Primarily, the generation of reactive oxygen species (ROS), including singlet oxygen (1O2), played a pivotal role. This was complemented by direct electron transfer from the contaminant to the catalyst-PMS complex, augmented by contributions from Mn(IV) species derived from the complex. This study not only presents a compelling instance of antibiotic degradation through multi-pathway activated PMS but also sheds light on the remarkable synergistic effects achieved by combining manganese oxide with boron and nitrogen compounds.

Tuning intramolecular charge transfer of covalent organic frameworks with triazine structure for enhanced peroxymonosulfate activation performance on the catalytic degradation of organic pollutants under visible light irradiation

As emerging metal-free photocatalysts, covalent organic framework with triazine structure (CTF) hold great potential for refractory organic pollutants removal in the visible-light-induced peroxymonosulfate system (PMS/Vis). In this work, the electron-withdrawing group(ketone structure) was introduced into the CTF framework (keto-CTF), aiming to regulate the regional electronic structure of CTF and thus further enhancing its visible-light photocatalytic performance and PMS activation. The results showed that the introduction of ketone greatly enhanced the visible-light utilization, carrier separation and intramolecular charge transfer capabilities of CTF. Notably, the keto-CTF/PMS/Vis system with resistance to environmental factors exhibited highly efficient and stable catalytic performance for the degradation and mineralization of organic pollutants, which was superior to that of single catalytic system. Indeed, the excellent photocatalytic performance and PMS activation of keto-CTF were attributed to the enriched valence-electron density around O atoms of ketone compared to that of C atoms, which led to a multitude of internal electric fields within the keto-CTF consisting of positive and negative electric centers. These internal electric fields not only promoted the separation and intramolecular transfer of photogenerated charges but enhanced the adsorption of PMS onto keto-CTF. The adsorbed PMS subsequently captured photogenerated charges, further reducing electron-hole recombination in keto-CTF and generating various reactive species. Ultimately, the efficient degradation of organic pollutants was achieved via the co-dominance of hole and singlet oxygen with the assistance of the charge-transfer-based non-radical pathway. This work provides new insights into the visible-light-induced multi-path catalytic oxidation mechanism of PMS and provides an effective solution for the removal of refractory organic pollutants from wastewater.

Enhanced peroxymonosulfate activation via MOF-derived bimetal core-shell Co-Fe@NC hybrids to degrade emerging pollutants

The reasonable control of the structure of metal–organic frameworks (MOFs) is a promising strategy for improving their peroxymonosulfate (PMS) activation activity. In this study, ZIF-67 @ZIF-8 was used as a template to prepare bimetallic core–shell Co-Fe@NC via Fe doping and high-temperature carbonization. Co-Fe@NC maintained the core–shell structure of the original MOF, in which cobalt was uniformly distributed in the nitrogen-doped graphite carbon skeleton and the surface of the graphite carbon skeleton was covered with iron. With the synergistic effect of the nitrogen-doped graphite carbon skeleton, iron, and cobalt, 100% of tetrabromobisphenol S (TBBPS) was removed in 60 min with kobs = 0.062 min−1 in Co-Fe@NC-0.2/PMS system. The addition of iron increased the graphitization degree with ID/IG value increased from 0.98 (Co@NC) to 1.034 (Co-Fe@NC-0.2) and electron transfer rate of the carbon skeleton. Besides, the Co leaching was effectively attenuated from 1.86 mg/L(Co@NC) to 0.78 mg/L (Co-Fe@NC-0.2) by the core-shell structure and bimetal strategy. Both O2·- and 1O2 contributed to the degradation of TBBPS according to quenching experiments. TBBPS was deeply degraded into small-molecule compounds through three degradation pathways by the Co-Fe@NC-0.2/PMS system. This study provides a new strategy for designing highly efficient bimetal–carbon composites for environmental remediation.

Theory-guided unraveling of the mechanism underlying Cu1.0/Mn1.0-ZnO with dual reaction centers for enhanced peroxymonosulfate activation

Developing efficient catalytic systems for water contamination removal is a topic of great interest. However, the use of heterogeneous catalysts faces challenges due to insufficient active sites and electron cycling. In this study, results from first-principles calculations demonstrate that dual reaction centers (DRCs) are produced around the Cu and Mn sites in Cu1.0/Mn1.0-ZnO due to the electronegativity difference. Experimental results reveal the material with DRCs greatly enhances electron transfer efficiency and significantly impacts the oxidation and reduction of peroxymonosulfate (PMS). In addition, the self-consistent potential correction (SCPC) method was introduced to correct the energy and charge of charged periodic systems simulating a catalytic process, resulting in more precise catalytic results. Specifically, the material exhibits a preference for adsorbing negatively charged PMS anions at electron-deficient Mn sites, facilitating PMS oxidation for the generation of 1O2, and PMS reduction around the electron-rich Cu for the formation of •OH and SO4•−. The major reactive oxygen species is 1O2, showcasing effective performance in various degradation systems. Overall, our work provides novel insights into the persulfate-based heterogeneous catalytic oxidation process, paving the way for the development of high-performance catalytic systems for water purification.

Carbon quantum dots assisted BiFeO3@BiOBr S-scheme heterojunction enhanced peroxymonosulfate activation for the photocatalytic degradation of imidacloprid under visible light: Performance, mechanism and biotoxicity

A novel S-scheme heterojunction photocatalyst carbon quantum dots (CQDs)/BiFeO3/BiOBr (CBB) was synthesized via a facile hydrothermal method, which was highly effective in activating peroxymonosulfate (PMS) to photodegrade imidacloprid (IMD) (one of the typical neonicotinoid insecticides (NEOs)) under visible light irradiation. Based on the physicochemical and photoelectrochemical analysis, the super photocatalytic performance of the CBB photocatalyst was contributed to the enhanced separation and transfer of photogenerated electrons (e−) and holes (h+), the activation of PMS by reactive species, and the wider light absorption range induced by CQDs. Moreover, the intermediate products and possible photodegradation pathways of IMD were confirmed through high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) detection and density functional theory (DFT) calculations. Although the photodegradation of IMD in the CBB/PMS/Vis system can be affected by the water quality parameters (i.e., acid group anions, pH, and the presence of humic acid (HA)), the synthesized CBB photocatalyst showed excellent photocatalytic performance in multiple natural water samples. This study provides a new idea to construct an effective and efficient heterojunction photocatalyst, which may have great advantages in photocatalytic degradation of NEOs and possibly other emerging contaminants in the aquatic environment.

Electronic interaction between biochar and montmorillonite toward enhanced peroxymonosulfate activation

Biochar works as the catalyst for activating peroxymonosulfate (PMS) to produce highly oxidizing radicals to remove organic contaminants from wastewater, but its activity requires further improvement. Recent research demonstrates that the PMS activation performance of biochar is closely related to the oxygen-containing functional groups (OFGs). Therefore, biochar/montmorillonite (BC/Mt) composites are designed for activating PMS toward degrading tetracycline. The negative charge of Mt. induced the electron transfer form Mt. to BC, which increases the nucleophilicity of CO groups that promote the activation of PMS to •OH and SO4•− radicals. Meanwhile, the pyrolysis path of rice straw is tuned by Mt., and the amount of COO groups is increased from 8.99% to 9.79% that promotes the generation of 1O2. Moreover, electron paramagnetic resonance and quenching experiments reveal that the activation mechanism of PMS by the BC/Mt. is comprised of both the radical and the non-radical pathway. Consequently, the tetracycline degradation kinetics using the optimized BC/Mt. (0.117 min−1) is higher than either bare BC (0.0866 min−1) or bare Mt. (0.0258 min−1), highlighting the significance of the rational design of electrocatalysts toward the enhanced catalytic chemistry. This work provides a facile route to improve the catalytic performance of biochar by hybridizing with clay minerals and is of great significance to promote the practical application of PMS-based advanced oxidation processes.

Enhanced Peroxymonosulfate Activation by a Benzoquinone-Functionalized Carbon Nanotube Filter for Micropollutant Degradation

Enhanced Peroxymonosulfate Activation by a Benzoquinone-Functionalized Carbon Nanotube Filter for Micropollutant Degradation

Enhanced peroxymonosulfate activation by MoS2/NiCo2S4 composite catalyst for efficient elimination of tetracycline hydrochloride

Compared to metal oxide, owing to the sulfur's lower electronegativity, metal sulfide is a promising catalyst. Molybdenum disulfide (MoS2) has been used as a catalyst or co-catalyst in the technology of peroxymonosulfate (PMS) activation due to its conductivity and rich active sites. In this work, MoS2/NiCo2S4 composite was synthesized successfully as an effective catalyst to activate PMS for removal of tetracycline hydrochloride (TCH). Catalyst screening indicated the composite with a Mo:Co molar ratio of 0.5:1 (0.5-MoS2/NiCo2S4) exhibited the best PMS activation performance. The results showed that 98.3% of TCH (15 mg/L) was removed, and the removal efficiency of total organic carbon (TOC) was 54.5% within 90 min under conditions of an Oxone dosage of 400 mg/L and a catalyst dosage of 300 mg/L. The main active substances were found to be sulfate radicals (SO4•−), hydroxyl radicals (•OH), superoxide radicals (O2•−) and singlet oxygen (1O2) in 0.5-MoS2/NiCo2S4/PMS system based on the active species quenching tests and electron paramagnetic resonance (EPR) analyses. A potential activation mechanism for the 0.5-MoS2/NiCo2S4/PMS system was proposed in the following two aspects: one is that molybdenum and sulfur species enhanced the cyclic transformation of Co3+/Co2+ and Ni3+/Ni2+ in the reaction system, and the other is the synergy of Co3+/Co2+, Ni3+/Ni2+ and Mo6+/Mo4+ cycles in the PMS activation. In summary, owing to its high activity and reusability, the 0.5-MoS2/NiCo2S4 composite is a promising catalyst for wastewater treatment.