Electron Paramagnetic Resonance Results Research Articles

Highly Effective Fe-Doped Nano Titanium Oxide for Removal of Acetamiprid and Atrazine under Simulated Sunlight Irradiation

Pesticides are widely detected in large quantities in the environment, posing an ecological threat to the human body and ecology. Semiconductor nanomaterials such as nano-titania (nTiO2) have strong photocatalytic degradation efficiency for pollutants. However, the wide bandgap and limited light absorption range inhibit nano-titania’s practical application. Therefore, nTiO2 was modified by Fe3+ doping using the microwave hydrothermal method to improve its photocatalytic performance in this study. Fe-nTiO2 doped with a 1.0% mass ratio was used due to its high photocatalytic performance. Its maximum degradation efficiencies for ACE and ATZ under a 20 W xenon lamp were 88% and 88.5%, respectively. It was found that Fe3+ doping modification distorted the spatial morphology of nTiO2 and shortened the bandgap to facilitate the photocatalytic reaction. The electron paramagnetic resonance results showed that the reactive radicals (1O2, ·OH) produced by photogenerated electrons (e−) and holes (h+) of Fe-nTiO2 were the main active species in the degradation of ACE and ATZ. Additionally, the application of Fe-nTiO2 significantly enhanced the growth of lettuce under sunlight; the degradation efficiencies of ACE and ATZ in lettuce were 98.5% and 100%, respectively. This work provides new insights into the removal of organic contaminants by photocatalysts under sunlight in agriculture.

Evaluation of gamma irradiation effects on antioxidant capacity of propolis

The irradiation effects on antioxidant potential and on content of phenolic compounds of propolis ethanoic extracts were studied. It was found out that gamma treatment of samples with 2 and 10 kGy had a weak decreasing effect on the total phenolic content (TPC), while no change was observed in the propolis irradiated with 5 kGy. The antiradical activity of extracts was assessed by the DPPH free radical scavenging activity evaluated by Electron Paramagnetic Resonance (EPR) spectroscopy. The EPR results were in agreement with TPC. Some main phenolic compounds of the studied non-irradiated and irradiated samples were identified and compared by ultra-high performance liquid chromatography (UHPLC).

Oxygen vacancy-rich cuprous oxide microspheres exhibit strong absorption and high oxidative energy level for deep photodegradation of tetracycline

In this study, a Cu2O microsphere (WY1) was hydrothermal synthesized by employing a CTAB-cocoylsarcosine sodium composite micellar. WY1 has an unifirm hollow spherical structure formed by agglomeration of nanoparticles, and the results of X-ray photoelectron spectroscopy and electron paramagnetic resonance indicate that WY1 contains significantly increased oxygen vacancies. The degradation efficiency of WY1 for 40 mg L−1 TC reached 93.26% after 60 min visible-light irradiation, which was 2.04 times higher than that of the product prepared without soft template (WNT). Especially, 81.67% residual rate of total organic carbon in the degradation of TC over WY1 was 17.83 times higher than that of WNT (4.58%). The spectral and electrochemical data reveal that the position of valence band of WY1 was exceeded the H2O/·OH potential, and the ·OH species rarely played a key role in the photocatalytic degradation of tetracycline by cuprous oxide. In addition, the ·O2− species were generated by forming the electron transfer pathway with aid of oxygen vacancy-mediated trap, acting as another major active species, which followed a deep photodegradation mechanism of hydroxyl and superoxide radicals dual activities. The spatial agglomeration of cuprous oxide nanoparticles provides a new process for enhancing interfacial energy levels and inhibiting photocorrosion, which cater the antibiotic remediation.

Defect engineered N-S codoped TiO2 nanoparticles for photocatalytic and optical limiting applications: Experimental and DFT insights

N-S codoped TiO2 nanoparticles (NPs) were synthesized using a sol–gel cum hydrothermal approach, with ammonium sulfate as the nitrogen and sulfur source compound. The calcination temperature was varied from 500 to 700 °C. The pristine samples exhibited a mixed phase of anatase and brookite, while the doped samples exhibited only the anatase phase, as confirmed by X-ray diffraction (XRD) analysis. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of N-H vibrations and S-O bidentate complexation with Ti4+ ions. Electron paramagnetic resonance (EPR) revealed the presence of Ti3+ signals, confirming the creation of oxygen defects in the doped samples. The absorption and emission properties of the samples were investigated using ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopy. Vibrating sample magnetometry (VSM) analysis confirms the room-temperature ferromagnetic behavior of the N-S doped TiO2, which was attributed to the presence of oxygen vacancies, as evidenced by the EPR and PL results. The N-S doped TiO2 samples demonstrated superior photocatalytic degradation of Rhodamine B (RhB), Methylene Blue (MB), and Congo Red (CR) dyes under visible light illumination compared to the pristine TiO2. This enhanced performance was attributed to the presence of N and S dopants in TiO2, which create new energy levels within the band structure of TiO2, allowing for efficient absorption of visible light and subsequent generation of reactive species for dye degradation. N-S doping modifies the electronic structure of TiO2, enhancing two-photon absorption (TPA). This increased TPA efficiency suggests promising applications in optical devices, such as laser protection systems and optical limiters. Density Functional Theory (DFT) investigation also confirms that the presence of oxygen vacancies generates energy states below the conduction band. This, in turn, benefits the absorption of more visible light during photocatalytic activities and leads to a notable nonlinear absorption in optical limiting. Overall, the N-S doping strategy significantly improves the photocatalytic and optical limiting performance of TiO2 NPs, making them promising candidates for a wide range of applications.

Synergistic mechanisms between chlorine-mediated electrochemical advanced oxidation and ultraviolet light for ammonia removal

The combination of chlorine-mediated electrochemical advanced oxidation (Cl-EAO) and ultraviolet (UV) radiation (UV-E/Cl) can efficiently remove ammonia from wastewater. However, the synergistic mechanisms between Cl-EAO and UV need to be explored in more detail. Thus, in this study, the ammonia oxidation performance of Cl-EAO and UV-E/Cl systems were compared, while the synergistic mechanisms were identified by the performance of UV/chlorine oxidation (UV–ClO) system and the results of electron paramagnetic resonance (EPR) analysis, free radical inhibition assays, and determination of steady-state concentration of free radicals. It was found that, compared with the Cl-EAO system, UV increased the ammonia removal rate by 42.85% and reduced the active chlorine concentration (56.64%) and nitrate yield (53.61%). In the Cl-EAO, and UV-E/Cl systems, Cl• were detected, and the free radical inhibition assays and determination of steady-state concentration of free radicals suggested that UV increased the concentration of Cl• by 51.47%, resulting in Cl• becoming the major contributor to ammonia oxidation in the UV-E/Cl system. Besides, UV also increase the concentrations of HO• and Cl2•-, which further promoted the organic matter removal in the real domestic wastewater. This study also discussed the ammonia oxidation performance of the UV-E/Cl system in real domestic wastewater, even with the presence of significant levels of organic and inorganic anions in the wastewater, UV increased the ammonia oxidation by 21.95%. The results of this study thus clarify the mechanisms and potential applications of UV-E/Cl technology.

Construction of Co-doped Fe2O3/carbonized melamine foam heterogeneous catalyst for enhanced degradation of organic pollutants through peroxymonosulfate activation

Co-doped Fe2O3/carbonized melamine foam heterogeneous catalyst (CMF/Co-Fe2O3) was prepared by hydrothermal method. Rhodamine B (RhB) degradation was employed as a model test for evaluating peroxymonosulfate (PMS) activation. The degradation efficiency of RhB can reach 97 % in the catalyst dosage (50 mg/L), PMS concentration (100 mg/L), pH = 7 and RhB initial concentration (10 mg/L) after 60 min reaction. The reaction rate constant is 10 times higher than that of CMF/Fe2O3 and the activation ability of PMS is greatly improved. The degradation efficiency of RhB can be inhibited by increasing the initial mass concentration of RhB and pH value. The effect of temperature on the degradation rate of RhB conforms to the Arrhenius model, and the degradation process is a surface reaction controlled process. The results of free radical capture experiments and electron paramagnetic resonance (EPR) experiments showed that SO4¯ was the main active free radical for RhB degradation. After four cycles, the degradation efficiency of RhB still maintains 80 % with CMF/10 %Co-Fe2O3 catalyst. The heterogeneous catalyst exhibited potential application in the field of degradation of dye wastewater due to its excellent cycling stability.

A magnetically reusable Ce-MOF/GO/Fe3O4 composite for effective photocatalytic degradation of chlortetracycline.

Herein, we report a novel 1/GO/Fe3O4 photocatalyst, comprising Ce(BTB)(H2O) (MOF-1, H3BTB = 1,3,5-benzenetrisbenzoic acid), graphene oxide (GO), and iron oxide (Fe3O4) for photocatalytic degradation of chlortetracycline (CTC). This design enables the effective transfer of electrons from the MOF to GO, thereby reducing the photoelectron-hole recombination rate. Therefore, the optimized 1/GO/Fe3O4 photocatalyst with H2O2 shows the highest photocatalytic activity toward CTC. The kinetic constant is 5.4 times that in the system of MOF-1 and hydrogen peroxide, which usually acted as efficient electron acceptors to improve the photocatalytic performance of MOFs. More importantly, light absorption is extended from the ultraviolet to the visible region. Furthermore, 1/GO/Fe3O4 can be quickly recycled under an applied magnetic field and displays outstanding stability and reusability. According to the radical trapping experiments and electron paramagnetic resonance results, hydroxyl radicals, superoxide radicals, and holes all contribute to excellent photocatalytic activity. The possible catalytic mechanism of 1/GO/Fe3O4 is tentatively proposed. This work aims to explore the synergistic effect between metal-organic frameworks (MOFs) and GO, and provide a theoretical basis for MOF-based composites to remove antibiotic contaminants in the environment.

Investigation of α-Fe2O3 catalyst structure for efficient photocatalytic fenton oxidation removal of antibiotics: preparation, performance, and mechanism.

Currently, the surface structure modification of photocatalysts is one of the effective means of enhancing their photocatalytic efficiency. Therefore, it is critically important to gain a deeper understanding of how the surface of α-Fe2O3 photocatalysts influences catalytic activity at the nanoscale. In this work, α-Fe2O3 catalysts were prepared using the solvothermal method, and four distinct morphologies were investigated: hexagonal bipyramid (THB), cube (CB), hexagonal plate (HS), and spherical (RC). The results indicate that the hexagonal bipyramid (THB) exhibits the highest degradation activity towards tetracycline (TC), with a reaction rate constant of k = 0.0969 min-1. The apparent reaction rate constants for the cube (CB), hexagonal plate (HS), and spherical (RC) morphologies are 0.0824, 0.0726, and 0.0585 min-1, respectively. In addition, it has been observed that the enhancement of photocatalytic activity is closely related to the increase in surface area, which provides more opportunities for interactions between Fe2+ and holes. The quenching experiments and electron paramagnetic resonance (EPR) results indicate that the ˙O2, ˙OH and h+ contribute mainly to the degradation of TC in the system. This research contributes to a more comprehensive understanding of catalyst surface alterations and their impact on catalytic performance.

NADPH oxidase-dependent free radical generation and protein adduct formation in neutrophils.

Neutrophils mediate the early innate immune response through extracellular traps comprising intracellular protein and DNA. These traps play a pivotal role in both immunity against invading pathogens and the development of immunopathological reactions through the production of reactive oxygen species (ROS). Proteins serve as the main target for ROS, resulting in the formation of protein adducts. Herein, we report that the superoxide anion radical (O2˙-) plays a vital role in neutrophil function through sequential events involving 5-lipoxygenase (5-LOX) and NADPH oxidase (NOX). More specifically, differences in NOX homologs expression were observed post-stimulation with PMA and LPS. Differentiation conditions and O2˙- generation were confirmed using flow cytometry. Immunoblotting analysis confirmed the time-dependent expression of NOX underlying its requirement and 5-LOX-mediated lipid peroxidation events in neutrophil function. Protein-malondialdehyde (MDA) adducts formed were detected using immunoblotting, and quercetin was evaluated for its ability to scavenge free radicals through electron paramagnetic resonance (EPR) spin-trapping spectroscopy and results were confirmed with blotting analysis. Free radical-mediated protein oxidation events influence neutrophil function and protein adducts formed serve as markers of neutrophil activation upon infection and inflammation. The study warrants further corroboration and the study of specific proteins involved in neutrophil activation and their role in inflammation.

Spin polarization engineering on SnS2 for improving photocatalytic disinfection

With the emergence and massive spread of antibiotic-resistant bacteria, it is urgent to develop new bactericidal technologies. Photocatalytic sterilization is a technique that uses solar energy to produce reactive oxygen species to kill pathogenic bacteria, and ROS effects depends on the charge separation characteristics of photocatalysts, so the development of strategies to promote charge separation is crucial. Here, we use the strategy of introducing sulfur vacancy on SnS2, effectively improving the separation of photogenerated charge. The femtosecond transient absorption results confirm that the charge lifetime of SnS2 (Sv-SnS2) after the introduction of the sulfur vacancy is 13.33 times that of pristine SnS2. The DFT theoretical results confirm that sulfur vacancy causes spin polarization. It is easier to separate when the spin direction of the electrons and holes changes. In addition, the sulfur vacancy also expands the light absorption range and exposes the surface catalytic site. These phenomena lead to a higher ROS yield of Sv-SnS2 (confirmed by electron paramagnetic resonance results). Thus, Sv-SnS2 killed 99.99 % of E. coli and MRSA within 40 min under visible-light illumination. This efficient bactericidal performance can be attributed to improved photogenerated charge separation. This study confirms the effectiveness of sulfur vacancy strategy to improve charge separation and extend charge life, and applies it to the killing of antibiotic resistant bacteria, providing a new idea for the killing of resistant bacteria.

A hierarchical 3D hybrid CoAl-layered double hydroxide/TiO2/Ti3C2 MXene S-scheme photocatalyst with 2D/0D/2D contact interfaces for sustainable pollutant degradation

Environmental pollution, particularly that derived from waterborne antibiotics, is a rising concern because of its detrimental effects on aquatic ecosystems and human health. Hence, in this study, we present a hierarchical 3D-structured hybrid photocatalyst comprising a CoAl-layered double hydroxide (LDH), TiO2, and Ti3C2 MXene synthesized using an in situ hydrothermal method. Various characterization techniques revealed that the hybrid CoAl-LDH/TiO2/Ti3C2 photocatalyst exhibited improved optical absorption, and the tailored 2D/0D/2D contact interfaces among the constituents enhanced charge migration and minimized electron-hole recombination. The results of electron paramagnetic resonance and in situ-irradiated X-ray photoelectron spectroscopy analyses confirmed that the hybrid photocatalyst follows an S-scheme mechanism that not only promotes the separation of photoinduced electron-hole pairs but also preserves their robust redox capability. The amalgamation of the three components resulted in synergistic advantages. Consequently, the optimized CoAl-LDH/TiO2/Ti3C2 photocatalyst exhibited remarkable performance in degrading and mineralizing the antibiotic diclofenac sodium (DFS) and the dyes rhodamine B and indigo carmine, surpassing its constituents and previously reported photocatalysts. Furthermore, the hybrid retained high efficiency across multiple cycles, underscoring its potential reusability. Therefore, this study demonstrates the potential of the developed hybrid photocatalyst for sustainable water treatment, thereby fostering cleaner aqueous environments.

Amino acid promoted oxidation of atrazine by Fe3O4/persulfate

In the present study, we demonstrated that the presence of cysteine could remarkably enhance the degradation of atrazine by Fe3O4/persulfate system. The results of electron paramagnetic resonance (EPR) spectra confirmed the combination of cysteine and Fe3O4 exhibited much higher activity on activation of persulfate to generate more SO4•- and •OH than Fe3O4 alone. At pH of 3.0, SO4•- and •OH contributed to about 58.2 % and 41.8 % of atrazine removal respectively, while •OH gradually dominated the oxidation of atrazine from neutral condition to alkaline condition. The co-existing Cl− and HCO3− could quench SO4•-, resulting in the inhibition of atrazine degradation. The presence of low natural organic matters (NOM) concentration (0–2 mg L−1) could enhance the atrazine removal, and high concentration (>5 mg L−1) of NOM restrained the atrazine degradation. During the Cysteine/Fe3O4/Persulfate process, cysteine served as a complexing reagent and reductant. Through acidolysis and complexation, Fe3O4 could release dissolved and surface bound Fe2+, both of which contributed to the activation of persulfate together. Meanwhile, cysteine was not rapidly consumed due to a regeneration process, which was beneficial for maintaining Fe2+/Fe3+ cycle and constantly accelerating the activation of persulfate for atrazine degradation. The reused Fe3O4 and cysteine in the Cysteine/Fe3O4/Persulfate process exhibited high stability for the atrazine degradation after three cycles. The degradation pathway of atrazine included alkylic-oxidation, dealkylation, dechlorination-hydroxylation processes. The present study indicates the novel Cysteine/Fe3O4/Persulfate process might be a high potential for treatment of organic polluted water.

An electron paramagnetic resonance study of the electron transport in heavily Si-doped high Al content AlxGa1−xN

High Al mole fraction AlGaN is an ultrawide bandgap semiconductor with potential applications in power electronics and deep UV detectors. Although n-type material is achievable with Si-doping, the role of Si is controversial, particularly for AlxGa1−xN with x > 0.8. For this paper, AlGaN films were grown by plasma-assisted molecular beam epitaxy onto bulk AlN substrates and doped with 1018–1020 cm−3 Si. We examine electron transport in heavily Si-doped AlxGa1−xN with x ≥ 0.65 using magnetic resonance, which allows us to probe the neutral donors directly rather than the free carriers and avoids complications due to electrical contacts. Transport was studied through the temperature-dependent linewidth of the electron paramagnetic resonance (EPR) signature for the neutral donor. Analysis shows evidence of hopping conductivity in the most lightly doped samples and impurity band formation in the most heavily doped ones. The EPR results, which are consistent with Hall measurements performed on the same samples, are promising for the development of highly conducting high Al content AlGaN.

Carbonized eggshell membranes as highly active co-catalyst with Fe3+/persulfate for boosting degradation of carbamazepine by accelerating Fe3+/Fe2+ cycle

The sluggish Fe3+/Fe2+ cycle greatly limits the effectiveness of the Fe3+-induced persulfate (Fe3+/PS) system for degrading refractory organic pollutants. Coupling Fe3+/PS system with a co-catalyst is a promising strategy to solve this issue. Herein, we report a carbonized eggshell membrane (CESM) as a potential co-catalyst to efficiently drive Fe3+/PS oxidation. The promotion effect of the CESM on the Fe3+/Fe2+ cycle resulted in the improvement in the activity of the Fe3+/PS system to degrade carbamazepine (CBZ), with ∼100 % CBZ removal achieved with low doses of Fe3+ (1.0 mg/L) and PS (100 mg/L). Crucially, a pseudo-first-order rate constant of CESM/Fe3+/PS system was 18- and 28-times that of the Fe3+/PS and CESM/PS systems. Experimental and theoretical findings reveal that the phenolic –OH groups and carbon--center persistent free radicals in CESM are electron donors, while the nitrogen sites function as favorable Fe3+-adsorption sites. The electron transfer in CESM/Fe3+/PS system occurred between a CESM and an attached Fe3+, facilitating the generation of Fe2+ and thus contributing to the continuous activation of PS. The quenching and electron paramagnetic resonance results indicate that active oxygen radicals (O2•−,•OH and SO4•−) and Fe(IV) acted together to realize the efficient CBZ degradation. Moreover, this system exhibited good reusability and environmental adaptability in various real water matrices. The co-catalyst effect of CESM is expected to inspire the exploration of utilization of different waste-biomass-derived organic materials as co-catalysts in the Fe3+/PS system for water purification.

Establishment an integrable model for expansion the application of the electron spin resonance in materials science

Electron spin resonance (ESR) is a highly successful and widely employed characterization and imaging technique within the field of materials science. Consequently, it has found frequent application in materials domain. However, a substantial number of experimental ESR results in this field lack theoretical explanations due to the absence of precise ESR models. To quantitatively analyze ESR results in materials science, this study has developed an asymmetric ESR spectrum model and assessed its efficacy using twenty-two experimental datasets. This model is integrable and capable of estimating spin concentration. Furthermore, this research has sought to establish quantitative associations between key material preparation parameters and the double integral of ESR intensity. This model is poised to enhance the widespread utilization of ESR in materials science.

Natural Pyrite as a Catalyst for a Fenton Reaction to Enhance Xanthate Degradation in Flotation Tailings Wastewater

The efficient treatment of mineral-processing wastewater has attracted soaring interest recently. This study’s objective was to degrade xanthate from flotation tailings wastewater using a pyrite-catalyzed Fenton system. A sodium butyl xanthate (SBX) removal rate of more than 96% was achieved via the method under optimal conditions (a H2O2 concentration of 0.5 mM, a FeS2 concentration of 0.5 g/L, an initial SBX concentration of 100 mg/L, and a natural pH of 9.36 ± 0.5), which is 12.85% higher than with a H2O2 system. An appropriate concentration of natural pyrite can act as a catalyst to significantly improve the oxidation capacity of H2O2. Additionally, the results of electron paramagnetic resonance and quenching measurements suggest that hydroxyl radicals (•OH) are the main active species in the H2O2-FeS2 system. The possible reaction mechanism is proposed. The H2O2 adsorbs onto the pyrite surfaces and reacts with Fe2+, triggering the formation of •OH and Fe3+. The •OH most likely attacks the SBX that adsorbs on the pyrite surface or exists in the solution and promotes the transformation of the SBX anion (C4H9OCS2−) into the intermediate butyl xanthate peroxide (BPX, C4H9OCS2O−). Finally, BPX intermediates are likely further oxidized to smaller products such as SO42−, CO2, and H2O under the ongoing attack of •OH.

Mn-NSC co-doped modified biochar/permonosulfate system for degradation of ciprofloxacin in wastewater

Mn-Nitrogen-sulfur co-doped modified biochar (Mn-NSCX) is prepared by high-temperature pyrolysis and hydrothermal method, and its properties are analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). A metal-non-technical co-doping system was constructed and first used for PMS activation towards ciprofloxacin degradation. The results show that doping of Mn, N and S significantly improve the catalytic performance of activated PMS to degrade CIP, among which Mn-NSC2 exhibit the best catalytic performance, when the dosage of MN-NSC2 is 0.4 g·L−1, the concentration of PMS is 0.4 mmol·L−1, and the concentration of CIP is 20 mg·L−1. After 60 min, more than 99% of CIP can be removed, among which the CIP removal rate of BC/PMS is 43.6%, and the CIP removal rate of NSC5/PMS is 50.3%. The removal effect of CIP is greatly improved after the incorporation of manganese, attributing to the oxidation reaction between the PMS and manganese dioxide. The results of electron paramagnetic resonance (EPR) indicate that both free radicals (·SO4-,·OH) and non-free radicals (1O2) play important roles in the degradation of CIP, and 1O2 plays a foremost role in the degradation of CIP. Doping of Mn, N and S accelerate the electron transfer rate and improve the catalytic activity of the material. In this paper, the loading of metal oxides can increase the corresponding catalytic sites and promote electron transfer, thus promoting the ability of activated PMS to degrade organic pollutants. The metal modification not only improves the oxygen-containing groups of the material, but also promotes the activation of persulfate by metal oxidation on the surface of the material. A novel design and preparation strategy for catalyst is proposed to simultaneously achieve stable Mn-Nitrogen-sulfur co-doped modified biochar and improve the catalytic performance of biochar by adding Mn, S, and N.

In-situ construction of S-scheme Bi4O5I2/BiOI heterojunctions with enriched oxygen vacancies and enhanced photocatalytic properties towards destruction of rhodamine B and tetracycline

Herein, novel S-scheme Bi4O5I2/BiOI heterojunctions were in-situ obtained through a hydrothermal method and post-roasting of BiOI prepared with the assistance of coconut shell. Bi4O5I2/BiOI photocatalytic materials was investigated by a series of characterization techniques. Abundant oxygen vacancies (OVs) were generated during the roasting process, proven by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) results. The existence coconut shell in the preparation process can effectively enhance the separation efficiency of carriers of the samples fabricated. Photocatalytic activity of Bi4O5I2/BiOI toward destruction of rhodamine B (RhB) and tetracycline (TC) is 5.5 and 4.5 times of that of the blank BiOI, separately, and h+ plays a major role in the destruction reaction. This demonstration suggests that in-situ preparation of S-scheme heterojunctions by roasting of BiOI prepared with the assistance of coconut shell provides an effective path for preparation of highly efficient BiOI-based catalysts.

Multisite photocatalytic depolymerization of lignin model compound utilizing full-spectrum light over magnetic microspheres

Photocatalytic depolymerization is a high value-added approach for utilization of lignin. In this study, magnetic microspheres of FeCoRu@SiO2-TiO2 were synthesized by a co-precipitation method. Doping with CoOx and RuOx was used to improve the response to visible light, and doping with TiO2 was used to improve the response to ultraviolet light (λ<380nm). The lignin model compound depolymerization rate was >90%. The electron paramagnetic resonance results showed that the reaction occurred in two steps (aerobic phase and oxygen-free phase). Most of the O2- was produced in the first step by cleavage of C-O bonds. The second step was inhibited in an oxygen-free atmosphere. This research provides a valid method for enhancing the photocatalytic properties using full-spectrum light and exploring the lignin photocatalytic depolymerization mechanism. Further research is required to develop the catalyst properties and performance to produce radicals.

ZnO@ZIF-8: The construction of core-shell structures to a new reaction pathway for efficient TC degradation

Present situation of tetracycline antibiotic pollution in water bodies is serious. In this study, ZnO@ZIF-8 with core-shell and non-central symmetric piezoelectric material structure was synthesized by mechanochemical method, which exhibits excellent degradation properties: degradation rate of a 50 mg/L tetracycline solution after 40 min of vibration can exceed 90%. Experimental analysis has confirmed that the composite material has better piezoelectric performance. Additionally, the adsorption of pollutants by ZIF-8 can effectively shorten the reaction path, which breaks through the limitations of general solution reactions, thereby improving the catalytic reaction efficiency. Radical quenching and electron paramagnetic resonance results have demonstrated that ∙OH and ∙O2– are the main active radicals of the catalytic reactions in the solution. Finally, the study identified the products after tetracycline degradation. This work provides a fresh approach to the application of piezoelectric materials in sewage treatment.