Degradation Of Metronidazole Research Articles

Enhanced activation of sulfite by CoFe2O4-loaded with WS2 nanosheet with smooth surface for elimination and detoxification of metronidazole

In this study, cobalt ferrite-loaded tungsten disulfide (CoFe2O4@WS2) with different loading ratios was prepared by coprecipitation as a catalyst for activating sulfite in the degradation of metronidazole (MNZ) for the first time. Characterization analysis revealed that the heterogeneous catalyst possesses favorable surface properties and catalytic stability. The CoFe2O4@WS2/Na2SO3 (2:1) system exhibited the best catalytic performance under optimal conditions, achieving an impressive MNZ degradation efficiency of up to 95 % within 20 min. Quenching experiments and electron paramagnetic resonance tests indicated that oxysulfur radicals (SO3•−, SO4•− and SO5•−),1O2, •O2− and •OH generated during Na2SO3 activation and participates in the degradation of MNZ to varying degrees, while the redox cycles of Co2+/Co3+ and Fe2+/Fe3+ on the catalyst surface facilitated electron transfer, thereby promoting radical generation. Importantly, the synergistic effect between highly active W (Ⅳ) sites and unsaturated S on the catalyst surface effectively enhanced ion valence state recycling among various metal ions, ensuring continuous decomposition of sulfite, thereby facilitating sustained generation of ROS and the degradation of MNZ, confirming that WS2 played an excellent co-catalysis role. MNZ was degraded into various intermediates through three distinct pathways before ultimately mineralizing into inorganic small molecules. Toxicity analysis results indicated that the intermediate toxicity diminished with the reaction, reducing potential risks to aquatic ecosystem. Furthermore, findings demonstrated that the catalyst has excellent anti-interference ability, recyclability and low ion leaching rate. This study provides a novel approach for the efficient degradation of multiple organic pollutants using sulfites with promising application in practical water treatment.

Mechanistic and DFT studies on the degradation of metronidazole by cerium oxide-loaded iron-cobalt layered double hydroxide-activated calcium sulfite

In this study, Co3Fe-LDHs loaded with CeO2 were synthesized via a hydrothermal method, and the synthesized Co3Fe-LDHs@CeO2 exhibited excellent surface properties and structural stability. Moreover, Co3Fe-LDHs@CeO2 was first applied to activate CaSO3 for metronidazole (MNZ) degradation. The effects of the catalyst preparation ratio, initial pH, and coexisting substances in the system on MNZ degradation were investigated. At an initial pH of 7.0, when 0.2 g/L Co3Fe-LDHs@CeO2 and 2 mM CaSO3 were combined, 99 % of the MNZ at a concentration of 20 mg/L was eliminated in 60 min. The experimental results revealed the rapid activation of CaSO3 on the catalyst surface, where Ce plays a key role in the redox cycle between Co and Fe atoms. The loading of CeO2 enhanced the catalytic performance of Co3Fe-LDHs, as confirmed by density functional theory (DFT) calculations. The loading of Ce promoted the chemisorption of CaSO3 on the surface of Co3Fe-LDHs@CeO2, leading to the transfer of 1.48 electrons from sulfite to Co3Fe-LDHs@CeO2. These findings were consistent with the results of the electrochemical tests. SO4•- and •OH were identified as the primary active substances through electron paramagnetic resonance (EPR) and chemical probe experiments, accounting for 60.73 % and 32.81 %, respectively. By combining LC–MS and DFT calculations, three potential degradation pathways of MNZ were identified, with the intermediates found to be either nontoxic or have low toxicity. Even after being recycled five times, MNZ still showed 88 % degradation, demonstrating its exceptional reusability. Co3Fe-LDHs@CeO2 shows great potential for practical use in treating antibiotic wastewater due to its outstanding catalytic properties, anti-interference ability, reusability, and stability.

Enhanced activation of peroxymonosulfate by nanomagnetic CoFe2O4-CeO2/g-C3N4 composites as a heterogeneous catalyst for metronidazole degradation

Antibiotic-induced catastrophic pollution has the potential to migrate over vast distances through water, thereby posing a detrimental effect on both humans and the environment. The construction of a highly robust catalyst to activate peroxymonosulfate (PMS) has become a fascinating approach for treating such types of wastewaters. In this study, we have developed CoFe2O4-CeO2/CN catalysts using an impregnation-hydrothermal and ultrasonication method to efficiently degrade metronidazole (MNZ). The synthesized catalyst materials were analyzed through multiple characterization techniques in order to correlate the material properties and the degradation performance. The degradation trials exhibited that MNZ underwent complete degradation within 40 min in the CoFe2O4-CeO2/CN-2/PMS system, with a rate constant of 0.1354 min−1, nearly 5.29 times faster than the CoFe2O4-CeO2/PMS (0.0235 min−1) under optimal conditions ([catalyst] = 0.5 g/L, [PMS] = 0.5 mM, [MNZ] = 20 mg/L, pH = 6.72). The increased abatement of MNZ in CoFe2O4-CeO2/CN-2/PMS system could be attributed to the higher surface area of the CoFe2O4-CeO2/CN-2 (75.96 m2/g) catalyst in comparison to the CoFe2O4-CeO2 (53.98 m2/g), which enhances the catalytically active sites and improves the PMS activation reaction. Besides, the impact of several operational variables and influencing anions on MNZ degradation was researched as well. The generation of free radicals was confirmed by radical scavenging analysis and authenticated using electron paramagnetic resonance analysis. The mechanistic analysis established that the activation of PMS was initiated by the transformations of Co3+/Co2+, Fe3+/Fe2+, and Ce4+/Ce3+. Briefly, this research provides valuable perspective for future research regarding heterogeneous catalysis leveraging PMS activation to alleviate toxic contaminants.

Insight into peroxymonosulfate-assisted photocatalysis over acidified red mud-supported TiO2 composite for highly efficient degradation of metronidazole

Insight into peroxymonosulfate-assisted photocatalysis over acidified red mud-supported TiO2 composite for highly efficient degradation of metronidazole

Construction of an S-scheme heterojunction with ultra-fast charge transfer at the BP/MOF-808 interface for efficient visible light degradation of metronidazole in the environment

Emerging S-scheme heterojunctions provide catalysts with superior electron transfer pathways and strong redox capacities. Constructing S-scheme heterojunction with two-dimensional nanosemiconductors (with very narrow bandgaps) as interfaces to activate the redox capacity of organic semiconductors (with wide bandgaps) represents a novel method for achieving efficient visible-light photocatalytic degradation of antibiotics. In this study, a BP/MOF-808 S-scheme heterojunction was synthesized through an hydrothermal method. Under visible light excitation (λ = 460 nm), it was demonstrated that photogenerated electrons are transferred from MOF-808 to BP, thereby retaining strong redox capability within the catalytic system. The 3-BP/MOF-808 (300 mg BP) heterojunction exhibited optimal photocatalytic activity, approximately 27.77 times and 27.34 times higher than those of BP and MOF-808, respectively. The results of this work are expected to guide the design and transformation of S-scheme photocatalysts for efficient environmental degradation of antibiotics.

Unveiling electron transfer and radical transformation pathways in coupled electrocatalysis and persulfate oxidation reactions for complex pollutant removal

The degradation of multiple organic pollutants in wastewater via advanced oxidation processes might involve different radicals, of which the types and concentrations vary upon interacting with different pollutants. In this study, electrochemical activation of peroxymonosulfate (E/PMS) using advanced activated carbon cloth (ACC) as electrode was applied for simultaneous degradation of mixed pollutants, e.g., metronidazole (MNZ) and p-chloroaniline (PCA). 92.5 % of MNZ and 91.4 % of PCA can be degraded at the cathode and anode at a low current density and PMS concentration, respectively. The rate constants for the simultaneous removal of MNZ and PCA in the E/PMS/MNZ(PCA) system were 118 times and 6 times higher than those in the sole PMS system, and 2.5 times and 1.6 times higher than those in the E/Na2SO4/MNZ(PCA) system, respectively. Different electrochemical characteristics, EPR spectra and radical quenching tests verified that the degradation of MNZ and PCA in the optimal system proceeded primarily through non-radical-dominated oxidation, involving electron transfer and 1O2 effect. The system also exhibited low energy consumption (0.215 kWh/m−3·order−1), broad operational pH range, excellent removal efficiency for water matrix, and low by-products toxicity, indicating its strong potential for practical applications. The ACC, with its super stable, low cost, and electrochemical activity, make it as a promising materials applicable in the E/PMS system for degradation of multiple pollutants. The study further elucidated the mechanism of pollutant interaction with electrode materials in terms of radical and non-radical transformation, providing fundamental insight into the application of this system for treatment of complex wastewater.

The role of spectral matching in enhancing photocatalytic performance with TiO2-rGO catalysts for metronidazole wastewater elimination

The role of spectral matching in enhancing the photocatalytic degradation of metronidazole using TiO2-reduced graphene oxide (TiO2-rGO) systems is investigated in this study. A rapid, one-step microwave synthesis method was utilized to produce TiO2-rGO composites with varying proportions of graphene oxide. Characterization techniques, including X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM), were employed to elucidate the morphological and structural attributes of the photocatalysts, thereby facilitating their application in photocatalysis. Spectral matching between the photocatalytic material and the irradiation source was identified as critical to the methodology. Experiments conducted under LED light tailored to the absorption spectra of the catalysts demonstrated that the TiO2-rGO system with a 2 % GO composition achieved the highest metronidazole degradation efficiency, reaching 95 % degradation after 120 min of irradiation. Furthermore, the catalyst maintained high reusability, with only a 5 % decrease in efficiency after five cycles of reuse. The Electrical Energy per Order (EEO) was determined to be 3.51 kWh/m3, indicating the system’s high energy efficiency. The study emphasizes the real-world applicability of TiO2-rGO composites for wastewater treatment, particularly in terms of environmental sustainability and operational cost-effectiveness.

Degradation mechanism of metronidazole using persulfate activated by boron/copper doped biochar derived from Chlorella vulgaris

Chlorella biochar modified with boron and copper (B/Cu-BC) was created and used to break down the antibiotic metronidazole (MNZ) through peroxymonosulfate (PMS) activation. The physicochemical properties of B/Cu-BC were analyzed using SEM, BET, FTIR, XRD and XPS. The results showed that the modified Chlorella biochar, which included several oxygen-containing functional groups, exhibited a rise of 7.1 times in specific surface area and a rise of 8 times in pore volume compared to the unmodified variant. Under the optimal conditions, the B/Cu-BC+PMS system removed 86.6 % of MNZ in 90 min. The reaction mechanism of the system was confirmed by Quenching and electron paramagnetic resonance (EPR) experiments. The B/Cu-BC+PMS system was accompanied by SO4•-, •OH, •O2- and 1O2, in which •O2-was the main reactive oxygen species (ROS). The intermediates in the degradation process of MNZ were investigated using HPLC-MS, and two potential degradation pathways of MNZ were suggested. Finally, the toxicology of the intermediates from the MNZ degradation process was analyzed by toxicity estimation software tool. The bioconcentration coefficients and mutagenicity coefficients showed a significant decrease, indicating that the system could efficiently degrade the antibiotic MNZ in an environmentally friendly manner.

Core/shell K0.5Na0.5NbO3/g-C3N4 sono-photocatalyst: Synthesis and catalytic activities in degradation of metronidazole

The sono-photocatalysis, as a type of low cost, highly efficient and environment friendly technology, has been attracted on account of its potential in water environment optimization. In this work, different contents of g-C3N4 incorporated K0.5Na0.5NbO3/g-C3N4 nanorods were synthesized for the sono-photocatalysis of metronidazole. The synthesized catalysts were subjected various measurements for investigating their phase, microstructure, physical and chemical performance, as well as catalytic activities in different processes. The incorporation of g-C3N4 on the surface of K0.5Na0.5NbO3 leads to the formation of heterojunction, which benefits to higher separation efficiency of photoinduced electron-hole pairs and thus results in higher catalytic activity. It is found that the K0.5Na0.5NbO3/15 %g-C3N4 shows the highest degradation efficiencies in sonocatalysis (∼64.4 %), photocatalysis (49.5 %) and sono-photocatalysis (∼99.2 %). In sono-photocatalysis, the synergistic sonochemical and photochemical effects result in the higher degradation efficiency. The reactive species of •OH, h+, •O2− and 1O2 play key roles in degradation. The degradation mechanism and possible pathways were proposed on the basis of experimental results.

Improving carrier separation in ZnIn2S4 to boost photocatalytic degradation of metronidazole based on machine learning prediction, experimental verification and theory calculation

Carrier separation efficiency significantly impacts the photocatalyst performance for wastewater purification. However, there is no established theory to accurately guide carrier separation efficiency regulation. This study used machine learning to screen dopants to change the band gap of ZnIn2S4 (ZIS), thus precisely regulating the ZIS carrier separation efficiency. Nitrogen with 0.5 % of doping amount showed the best regulation effect. Metronidazole degradation kinetic rate with nitrogen doped ZIS (N/ZIS) was 1.47 times higher than that with ZIS. Real-time time-dependent density functional theory (rt-TDDFT) was employed to assess carrier separation at the orbital level. Experiments and rt-TDDFT confirmed that N/ZIS possessed better carrier separation efficiency than that of ZIS. An “in-situ” potential research strategy was established to determine carrier acceptors, which can compare the orbital potential of molecules and catalysts in the adsorption state. This approach revealed that O2 served as the photogenerated electron acceptor, while OH– functioned as the hole acceptor. H2O was not actively involved in carrier separation. O2 anti-bonding orbital activation effect by the catalysts was studied to unveil the influence mechanism of carrier separation efficiency on the photocatalyst activity. This study provides a new insight into carrier dynamics to design efficient photocatalysts.

Regulating facet exposure and sulfur vacancy in magnetic greigite nanosheet for boosting heterogeneous Fenton-like reaction towards efficient degradation of metronidazole under visible light irradiation: Synergistic enhancement effect, DFT calculations and mechanism insight

Environmentally friendly iron catalysts have attracted widespread attention in the heterogeneous Fenton-like reaction based on peroxymonosulfate (PMS) for the degradation of emerging pollutants in water, while it has always suffered from the disadvantage of low catalytic activity. Herein, we successfully prepared the magnetic greigite (Fe3S4) nanosheet with the exposed {011} facet and rich sulfur vacancies (FS-1) through a simple solvothermal method. The degradation rate of metronidazole by the FS-1 activating PMS under visible light irradiation was 2.93, and 4.48 more than those of the Fe3S4 nanosheet with the exposed {011} facet and poor sulfur vacancies, and Fe3S4 nanobulk with the exposed {112} facet, respectively. The result of electrochemical analysis and theoretical calculation indicated that the exposed {011} facet of prepared FS-1 offered more active sites to adsorb PMS, and the rich sulfur vacancies on the surface accelerated the electron transfer between oxidants and catalyst. This collaborative effect significantly lowered the energy barrier associated with PMS activation, leading to an increased generation of singlet oxygen. Additionally, the degradation mechanism and pathway of metronidazole, including hydroxyethyl cracking, denitrification, and hydroxylation, were explored in detail through theoretical calculations and high-performance liquid chromatography-mass spectrometry, respectively. This work offers insight into boosting the catalytic performance of environmentally friendly iron-based catalysts.

Facilitating interface tuning of metal-support interaction on the sepiolite surface for the enhancement of metronidazole removal

To achieve efficient catalytic activity for emerging contaminants degradation in water environment, this work creatively prepared a silicon-based catalyst (Co/ASepx), which built a metal-silicon framework in-situ growing on sepiolite (Sep) through hydrothermal synthesis, and further obtained via high-temperature pyrolysis. Then the Co/ASepx was used to activate peroxymonosulfate (PMS) to remove metronidazole (MNZ) from water environment. The results showed that the Co/ASepx presented a substantial number of Co/MgSiO3-Co interfacial structures, the introducing of interface engineering triggered the strong metal-support interaction between Co and Sep, then altered the surface electron distribution and regulated the coordination environment of the metal Co. The Co/ASep1-PMS system not only exhibited the significant MNZ removal performance, and the MNZ degradation rate in the Co/ASep1-PMS system was 5.4 times than that of the Co2+-PMS homogeneous catalytic system with the same Co dosage, but also presented low Co leaching and high cycling stability. Moreover, the quadruple mechanism of MNZ degradation were comprehensively revealed, in which was dominated by the singlet oxygen of the non-radical pathway. Lastly, this work provides a novel feasible way to build high-performance catalysts with low Co leaching and low cost for the outstanding removal efficiency of MNZ.

Synthesis and photodegradation performance of a heterostructure ferromagnetic photocatalyst based on MWCNTs functionalized with (3-glycidyloxypropyl)trimethoxysilane and decorated with tungsten trioxide for metronidazole and acetaminophen degradation in aqueous environments.

The presence of metronidazole (MNZ) and acetaminophen (ACE) in aquatic environments has raised growing concerns regarding their potential impact on human health. Incorporating various patterns into a photocatalytic material is considered a critical approach to achieving enhanced photocatalytic efficiency in the photocatalysis process. In this study, WO3 nanoparticles, which were immobilized onto ferromagnetic multi-walled carbon nanotubes that were functionalized using (3-glycidyloxypropyl)trimethoxysilane (FMMWCNTs@GLYMO@WO3), exhibited remarkable efficiency in removing MNZ and ACE (93% and 97%) in only 15 min. In addition, the new visible-light FMMWCNTs@GLYMO@WO3 nanoparticles as a magnetically separable photocatalyst were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), EDS-mapping, vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), diffuse reflectance spectroscopy (DRS), high-performance liquid chromatography (HPLC), and total organic carbon (TOC) due to detailed studies (morphological, structural, magnetic and optical properties) of the photocatalyst. In-depth spectroscopic and microscopic characterization of the newly developed ferromagnetic FMMWCNTs@GLYMO@WO₃ (III) photocatalyst revealed a spherical morphology, with nanoparticle diameters averaging between 23 and 39 nm. Compared to conventional multiwall carbon nanotube and WO₃ photocatalysts, FMMWCNTs@GLYMO@WO₃ (III) demonstrated superior photocatalytic activity. Remarkably, it exhibited excellent reusability, maintaining its efficiency over a minimum of five cycles in the degradation of metronidazole (MNZ) and acetaminophen (ACE).

Cobalt-Modified Biochar from Rape Straw as Persulfate Activator for Degradation of Antibiotic Metronidazole

A cobalt-loaded magnetic biochar (Co-MBC) catalyst was synthesized to enhance the removal of metronidazole (MNZ). Study explored the performance and mechanism of MNZ degradation by Co-MBC activated permonosulfate (PMS). Results showed that cobalt oxides were effectively deposited onto the biochar surface, new oxygen functional groups were added to the modified biochar, and the presence of the metallic element Co enhanced the efficiency of PMS activation in the composite. More than 90% of MNZ was removed after 60 min with a catalyst dosage of 0.2 g/L and a PS concentration of 1 mM. After four reuses, Co-MBC still showed excellent catalytic performance to degrade over 75% of MNZ. The reaction system performed well even in the presence of inorganic anions and organic macromolecules. However, the degradation rate was inhibited under alkaline conditions. The quenching experiment indicated that •SO4−, •OH, 1O2, and •O2− synergistically degraded MNZ, and that•SO4− played a dominant role. LC-MS was applied to assess intermediate degradation products, in which CO2, H2O, and NO3− were the final degradation products, and potential degradation pathways were suggested. In conclusion, Co-MBC was an efficient and stable catalytic material, and its ability to activate PMS was improved to effectively degrade antibiotics, a typical priority pollutant.

Synergistic degradation of metronidazole and penicillin G in aqueous solutions using AgZnFe2O4@chitosan nano-photocatalyst under UV/persulfate activation

In recent years, the persistence of pharmaceutical contaminants like metronidazole (MNZ) and penicillin G (PG) in water bodies has become a major environmental concern. The present research studied the simultaneous degradation of MNZ and PG utilizing an AgZnFe2O4@Ch catalyst generated through the co-precipitation technique as an effective stimulator for persulfate (PS) in the existence of UV light. The structure of the AgZnFe2O4@Ch catalyst was characterized using X-ray powder diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, vibrating-sample magnetometer, and energy dispersive spectroscopy mapping. After 50 minutes of reaction time under the ideal operating conditions, which included 0.4 g/L of catalyst, 4 mM of PS, 5 mg/L of MNZ and PG, and a pH of 5, the highest MNZ and PG degradation of 81.5 % and 82.3 % were obtained. Statistical parameters, including the R2 values of 0.985 for MNZ and 0.981 for PG, indicate a very good agreement between the predicted and observed values. The Garson's method analysis revealed that PS dosage had the greatest impact on MNZ degradation, while the initial concentration of PG exerted the most significant influence on PG degradation. The Langmuir-Hinshelwood model has surface reaction rate constants (Kc) of 0.954 (mg/L.min) and adsorption equilibrium constants (KL-H) of 0.032 (L/mg) for both antibiotics, respectively. The claimed mechanism was illustrated by the free radical scavenging studies, which demonstrated that the SO•4- radicals were the main radicals involved in the degradation of MNZ and PG. A last investigation of the catalyst's regeneration revealed that it had satisfactory chemical stability after five cycles of usage and regeneration using chemical approaches.

Removal of metronidazole using a novel ZnO–CoFe2O4@Biochar heterostructure composite in an intimately coupled photocatalysis and biodegradation system under visible light

The intimate coupling of photocatalysis and biodegradation (ICPB) technology has received much attraction because of the advantages of both photocatalytic reaction and biological treatment. In this study, ZnO–CoFe2O4@BC (ZCFC) with p-n heterojunction was prepared and used in an ICPB system to degrade metronidazole (MNZ) wastewater. The microstructure, morphology, and optical behavior of heterojunctions in ZCFC were investigated using SEM, XRD, UV–vis, FTIR, and XPS techniques. The results showed that ZCFC inherited the advantages of bamboo biochar's large pore size, and its large pore structure could provide a habitat for bacterial colonization in ICPB, thus shortening the internal mass transfer distance. The degradation of MNZ and chemical oxygen demand (COD) by the ICPB system was 86.8% and 58.5%, respectively, which was superior to single photocatalysis (72.5% for MNZ and 43.8% for COD) and single biodegradation (23.5% for MNZ and 20.1% for COD). In ICPB, photocatalysis and biodegradation showed a synergistic effect in the removal of MNZ, and the order of the major reactive oxygen species (ROS) leading to reduced toxicity of MNZ to the biofilm was •OH > h+ > O2•-. High-throughput sequencing analysis showed continuous evolution of biofilm structures in ICPB enriched a variety of functional species, among which the electroactive bacteria Alcaligenes and Brevundimonas played an important role in the degradation of MNZ. In this study, we investigated the possible mechanism of photocatalytic and microbial synergistic degradation of MNZ in the ICPB system and proposed a new technology for degrading antibiotic wastewater that combines the advantages of photocatalysis and biodegradation.

Mn-MOF derived N-doped MnOx@carbon heterogeneous catalysts for Vis-light, S2O82[sbnd], HSO5[sbnd], Vis/S2O82[sbnd], and Vis/HSO5[sbnd]-induced degradation of metronidazole: Kinetics and mechanistic study

Manganese oxide-based nanostructures have demonstrated remarkable potential for reactive radical generation to treat wastewater by activating persulfate (PS) and peroxymonosulfate (PMS) in the presence of visible-light irradiation. Herein, we report a facile strategy to synthesize nitrogen-doped porous MnOx@Carbon nanostructures by annealing Mn-based MOF at different temperatures and employed for the degradation of MTZ under Vis-light, PS, PMS, Vis/PS, and Vis/PMS systems. A significant catalytic synergy was found in the MnO-I/Vis/PMS system. Owing to the rational coordination of nitrogen-enriched porous manganese oxide embedded carbon, high surface area (179.6 m2/g), and surface-exposed abundant active sites, the composite named MnO-I exhibited excellent catalytic performance in all the studied processes. The carbonization process induces a polarization difference between Mn-N co-ordination, resulting in the carbon becoming an electron-deficient core and manganese an electron-rich center, thus providing more Mn (II/III) for PMS activation. The degradation study showed that 99 % removal of MTZ was achieved within 40 min, with a rate constant of 0.099 min−1, in the MnO-I/Vis/PMS system. Trapping experiments and EPR detection demonstrated that SO4•−, OH• and 1O2 radicals were the major species involved in the degradation process. Besides, the degradation pathway and impact of operational parameters, i.e., catalyst dosage, PMS concentration, initial pH, MTZ concentration, co-existing anions, and humic acid, on the removal of MTZ were also explored.

Design and Development of p-toluenesulfonic acid Functionalized Dual-functional Fe-MOF@SBC Heterogeneous Catalyst for Efficient Biodiesel Production and Photocatalytic Degradation of Metronidazole

Design and Development of p-toluenesulfonic acid Functionalized Dual-functional Fe-MOF@SBC Heterogeneous Catalyst for Efficient Biodiesel Production and Photocatalytic Degradation of Metronidazole

Nitrogen-doped carbon nanotube catalytic membrane with peroxymonosulfate activation for the degradation of metronidazole and bisphenol A: Performance and mechanism comparison

As typical pharmaceuticals and personal care products (PPCPs), metronidazole (MNZ) and bisphenol A (BPA) normally presented in sewage effluent and surface water. The nitrogen-doped multi-walled carbon nanotube (NCNT) membrane was prepared and utilized as a peroxymonosulphate (PMS) catalyst to degrade MNZ and BPA. Within the NCNT membrane/PMS catalytic system, MNZ and BPA can be efficiently degraded, while different catalytic degradation mechanism exists related with their structure, adsorption properties and even PMS dosage. The optimal conditions for the degradation of MNZ and BPA were investigated. Quenching tests and electron paramagnetic resonance examination demonstrated that •OH radicals and 1O2 played roles in MNZ degradation, while surface-bound radicals and 1O2 dominated BPA degradation within the NCNT membrane catalytic PMS system. Electrochemical tests proved that an electron-transfer process between NCNT membrane and PMS during MNZ degradation, and the electron-transfer process was further verified with the degradation experiment in the binary-solute system (BPA and MNZ). PMS dosage had little influence on the degradation mechanism of MNZ and BPA.

Microwave responsive copper-ferrite (CuFe2O4) encapsulated in molybdenum-disulfide (MoS2) nanoflower catalyst for antibiotic removal via persulfate oxidation

Microwave (MW) responsive copper-ferrite/molybdenum-disulfide (CuFe2O4/MoS2) nanoflower catalyst was implemented for rapid antibiotic metronidazole (MNZ) degradation via persulfate oxidation under MW irradiation. The catalyst was synthesized via co-precipitation followed by hydrothermal methods, and characterized by XRD, FTIR, SEM, TEM, VSM, XPS, and UV-DRS. As a first step, MW induced MNZ removal was studied at different initial mass of CuFe2O4/MoS2 (2.5–20%), where 5% CuFe2O4 in the nanocomposite performed the best. Within 5 min of MW irradiation, 100% MNZ removal was observed (Kobs ∼ 1.063 min−1) under the optimal reaction conditions (i.e., CuFe2O4/MoS2 dose ∼ 0.4 g/L; PS dose ∼ 100 mg/L; temperature ∼ 90 °C; and MW power ∼ 350 W). The MNZ removal was independent of solution pH 3–11, and the removal was by SO4•−and •OH radicals alongside the limited contribution from O2•−. PS and H2O were thermally decomposed to produce SO4•−and •OH radicals, whereas intrinsic semiconductor CFO/MS with a narrow bandgap of 1.53 eV allowed electrons to jump into conduction band from valance band to create SO4•− and O2•−. However, the performance of MW system was inhibited by the presence of anions in the order of Cl−< NO3− <CO32− <H2PO4−. Robustness of the CuFe2O4/MoS2 was proved via recyclability experiments, and MNZ removal was found to be dropped ∼ 4.89% at the end of 5th cycle. It was proposed that the absorbed MW energy was dissipated through various losses to generate ‘hotspots’ (>1200 °C) for MNZ removal. Synergistically, redox couples of transitional metals contributed to MNZ degradation.