Degradation Efficiency Of Tetracycline Hydrochloride Research Articles

Biochar coupling induced charge transfer switching of a NiAl2O4/NiCr2O4 photocatalyst to enhance photocatalytic degradation of tetracycline hydrochloride

A series of novel (NiAl2O4 (NAO)/NiCr2O4 (NCO)) (S1)/GL heterojunction photocatalysts, denoting as x%GL/S1 (x = 5, 10, 15 and 20), were prepared by the polyacrylamide gel method combined with low temperature sintering technique. Various characterizations confirm that there is special interfacial contact and charge transfer between NAO, NCO and GL. The 10%GL/S1 heterojunction exhibited the best photocatalytic activity and cyclic stability for the degradation of tetracycline hydrochloride (TC). Compared to NAO, NCO and NAO/NCO, the degradation efficiency of 10%GL/S1 was significantly improved, and the degradation percentage reached 83.2% within 30 min. The activity of 10%GL/S1 was studied in relation to catalyst content, drug concentration, pH value, water quality, and co-existing anion. Trapping experiments and free radical verification experiments confirmed that the holes, hydroxyl radicals and superoxide radicals played crucial roles in the photocatalysis process. Possible pathways for TC degradation were studied by HPLC-MS, and the ecotoxicity of TC and its degradation intermediates was evaluated by T.E.S.T. software. The charge transfer and photocatalytic mechanisms confirm that the introduction of GL enhances the interfacial interaction between the components, promotes the carrier migration efficiency, provides a large number of active sites for 10%GL/S1 heterojunction, and produces active free radicals after redox reaction with photoinduced electrons, effectively improving the degradation efficiency of TC.

Efficient Adsorption and Degradation of Tetracycline Hydrochloride Using Metal-Organic Framework-Derived Cobalt-Based Catalysts and Mechanism Insight.

High-performance Co-based catalysts were derived by pyrolysis using synthesized MOFs as self-sacrificial templates. Various catalytic systems were constructed by peroxymonosulfate (PMS) to degrade tetracycline hydrochloride (TC). Adsorption-degradation efficiencies, cycle performance, dynamics, and the adsorption catalytic mechanism of various catalytic systems for TC were studied. The effects of different synthetic solvents, pyrolysis temperatures, and single/bimetallic element compositions on degradation efficiency were innovatively compared. The optimal catalyst and PMS dosage for the experiment were determined to be 10 mg and 0.1 mL, respectively. The results indicated that all catalytic systems could efficiently degrade TC and have a high acid-base resistance. The catalyst activity was significantly influenced by the pyrolysis temperature. The optimum pyrolysis temperatures for Zn@Co-N-C-T, CH3OH@Co-N-C-T, and H2O@Co-N-C-T were 1000, 900 and 900 °C, respectively. More abundant pore structures and active sites were generated in Zn@Co-N-C-1000, exhibiting an excellent TC degradation efficiency and adsorption capacity, achieving 94.73% and 167.564 mg/g, respectively. Meanwhile, the total organic carbon (TOC) of TC (50 mL, 50 mg/L) achieved a removal rate (TOC/TOC0) of 50.28%. Zn@Co-N-C-1000/PMS maintained over 83.27% TC degradation after five cycles. The adsorption mechanism of the catalyst for TC was investigated through the analysis of adsorption kinetics and isotherm models. The quenching test and EPR results indicated that TC was primarily degraded through the nonradical pathway. The efficient degradation of TC is attributed to the rapid electron transfer processes occurring at the two-phase interface and the redox cycling of Co0/Co2+/Co3+. Finally, LC-MS was used to analyze the intermediate products of TC degradation in the Zn@Co-N-C-1000/PMS system, and two degradation pathways were proposed.

Improving photoexcited carrier separation through Z-scheme W18O49/BiOBr heterostructure coupling carbon quantum dots for efficient photoelectric response and tetracycline photodegradation

Building Z-scheme heterostructure integrating oxygen vacancies seems to effectively encourage photoexcited charge partition and hence photoelectric response and photocatalytic performance. Here, through the inclusion of carbon quantum dots (CQDs) with W18O49/BiOBr (WB) for enhancing electron exchange and band structure control, we have developed one Z-scheme ternary CQD/W18O49/BiOBr heterostructures (CWB) with intense oxygen vacancies. The optimal CWB heterostructure shows superior photocatalytic and photoelectric response execution. The findings indicate that CWB has higher photocatalytic degradation efficiency of tetracycline hydrochloride (TC) at 97 % compared to WB or W18O49 alone. Additionally, the CWB shows a higher photocurrent density, surpassing WB and W18O49 by 2.5 times and 5.4 times. A potential self-supplied photoelectrochemical-type photodetector utilizing CWB displays relatively quick and stable photoelectric response at 0 V. The improved photo-electric performance are linked to the combined impact of separation and redistribution of charges caused by Z-scheme heterostructure and oxygen vacancies, as well as intensive light absorbance by localized surface plasmon resonance. Our research also validates significance of CQDs as cocatalyst in accelerating the splitting of photo carriers in Z-scheme ternary CWB heterostructures, which will stimulate interest in creating advanced photoactive heterojunction substance with carbon nanomaterials.

N-doped carbon-coated CoSe2/ZnIn2S4 Z-scheme heterojunction for enhanced visible-light photocatalytic performances

N-doped carbon (NC)/CoSe2/ZnIn2S4 Z-scheme heterojunction was constructed by growing ZnIn2S4 on N-doped carbon-coated CoSe2 derived from the metal-organic framework (ZIF-67) via the self-sacrificing template method and hydrothermal method. X-ray photoelectron spectroscopy, electron paramagnetic resonance, and density-functional theory (DFT) calculations demonstrate that NC/CoSe2/ZnIn2S4 (NSZ) Z-scheme heterojunction was constructed with CoSe2 as an electron mediator. The optimal 5NSZ composite achieved 97.3% in photocatalytic degradation efficiency of tetracycline hydrochloride (TCH) within 30 min, and H2O2 production of 645.3 μM under visible light for 60 min. Moreover, the top-flight photocatalytic hydrogen evolution (PHE) rate of 6772.9 μmol g−1 h−1 is 19.1 folds and 2.2 folds higher than pure ZnIn2S4 and Pt–ZnIn2S4, respectively. The photoreduction CO2 gas produces rates of CO (53.7 μmol g−1 h−1), C2H4 (7.0 μmol g−1 h−1), and C2H6 (6.4 μmol g−1 h−1) products were obtained within 10 h under visible light. This work provides an effective strategy for designing unique noble-metal-free Z-scheme heterojunction photocatalysts to purify the environment and produce clean energy.

High Efficiency Removal Performance of Tetracycline by Magnetic CoFe2O4/NaBiO3 Photocatalytic Synergistic Persulfate Technology.

The widespread environmental contamination resulting from the misuse of tetracycline antibiotics (TCs) has garnered significant attention and study by scholars. Photocatalytic technology is one of the environmentally friendly advanced oxidation processes (AOPs) that can effectively solve the problem of residue of TCs in the water environment. This study involved the synthesis of the heterogeneous magnetic photocatalytic material of CoFe2O4/NaBiO3 via the solvothermal method, and it was characterized using different characterization techniques. Then, the photocatalytic system under visible light (Vis) was coupled with peroxymonosulfate (PMS) to explore the performance and mechanism of degradation of tetracycline hydrochloride (TCH) in the wastewater. The characterization results revealed that CoFe2O4/NaBiO3 effectively alleviated the agglomeration phenomenon of CoFe2O4 particles, increased the specific surface area, effectively narrowed the band gap, expanded the visible light absorption spectrum, and inhibited recombination of photogenerated electron-hole pairs. In the Vis+CoFe2O4/NaBiO3+PMS system, CoFe2O4/NaBiO3 effectively activated PMS to produce hydroxyl radicals (·OH) and sulfate radicals (SO4-). Under the conditions of a TCH concentration of 10 mg/L-1, a catalyst concentration of 1 g/L-1 and a PMS concentration of 100 mg/L-1, the degradation efficiency of TCH reached 94% after 100 min illumination. The degradation of TCH was enhanced with the increase in the CoFe2O4/NaBiO3 and PMS dosage. The solution pH and organic matter had a significant impact on TCH degradation. Notably, the TCH degradation efficiency decreased inversely with increasing values of these parameters. The quenching experiments indicated that the free radicals contributing to the Vis+CoFe2O4/NaBiO3+PMS system were ·OH followed by SO4-, hole (h+), and the superoxide radical (O2-). The main mechanism of PMS was based on the cycle of Co3+ and Co2+, as well as Fe3+ and Fe2+. The cyclic tests and characterization by XRD and FT-IR revealed that CoFe2O4/NaBiO3 had good degradation stability. The experimental findings can serve as a reference for the complete removal of antibiotics from wastewater.

One-step high-efficiency microwave synthesis of N-doped bamboo biochar for tetracycline degradation

N-doped bamboo biochar (NBB) was successfully synthesized through one-step, rapid pyrolysis (e.g., 10 min) using urea and urea nitrate impregnated bamboo particles exposed to low power (e.g., 460 W) microwave radiation. NBB-460 exhibited high specific surface area of 876.1 m2/g and outstanding catalytic performance for tetracycline hydrochloride (TCH) degradation. The TCH degradation efficiency reached to 94.3 % with the optimized catalytic condition (i.e., 0.2 g/L NBB-460, 3 mM PMS, 50 mg/L TCH, 25 ℃, without pH regulation). The density functional theory calculation showed that the graphitic nitrogen and pyridinic nitrogen of NBB-460 served as active sites for peroxymonosulfate activation and TCH degradation. The quenching test, electron paramagnetic resonance spectra, and electrochemical measurements indicated that tetracycline hydrochloride underwent degradation via radical (O2•−), non-radical (1O2) pathways, and surface electron transfer. This study introduces an energy-efficient and time-effective method for converting biomass to N-doped biochar as highly efficient peroxymonosulfate activator for environmental applications.

Strong Magnetic p-n Heterojunction Fe3O4-FeWO4 for Photo-Fenton Degradation of Tetracycline Hydrochloride

With the abuse of antibiotics, its pollution poses an increasing threat to the environment and human health. Effective degradation of organic pollutants in water bodies is urgent. Compared to traditional treatment methods, advanced oxidation processes that have developed rapidly in recent years are more environmentally friendly, efficient and applicable to a wider range of organic compounds. FeWO4 was used in this study as the iron-based semiconductor material to modify and optimize the material design. Fe3O4/FeWO4 composites were prepared by a two-step hydrothermal method. The crystal structure, surface morphology, electrochemical properties and separability of the composite semiconductor were analyzed by XRD, XPS, UV-vis, SEM, EDS and Mott-Schottky. The results showed that, when the initial contaminant concentration was 30 mg/L, the initial solution pH was 4, the dosage of the catalyst was 25 mg and the dosage of hydrogen peroxide was 30 μL, the degradation efficiency of tetracycline hydrochloride (TCH) could reach 91% within 60 min, which was significantly improved compared to the performance of the single semiconductors Fe3O4 and FeWO4. In addition, the catalyst prepared in this experiment can be easily recovered by magnetic separation technology in practical application, which will not affect the turbidity of water while reducing the cost of catalyst separation and recovery.

A novel circulating film reactor for enhance degradation efficiency of tetracycline hydrochloride via an Ag-AgVO3@BiVO4/PVDF composite film under visible light irradiation

Composite film materials have garnered significant attention in the realm of environmental remediation. An Ag-AgVO3@BiVO4/PVDF composite film was successfully fabricated through an ultrasound-assisted and in situ precipitation method. The porous nature of the PVDF film allows for ample space for the in-situ growth of Ag, AgVO3, and BiVO4, ultimately forming a stable heterostructure. The Ag-AgVO3@BiVO4/PVDF composite film exhibited superior photocatalytic activity, achieving a degradation rate of 88.3% for TC when utilized in a circulating film reactor of Type II, surpassing the performance of the intermittent reactor of Type I which yielded a degradation rate of 73.5%. Furthermore, the degradation rate was 2.64 and 1.24 times higher compared to Ag-AgVO3/PVDF (33.4%) and BiVO4/PVDF (71.1%) films, respectively. The composite film can be used for the removal of other organic compounds, achieving degradation rates of 70.6% for OFL and 80.6% for RhB, respectively. The composite film is easily recoverable and reusable, rendering it particularly well-suited for industrial wastewater treatment.

ZIF-67/natural coal gangue composite as hydrogen peroxide activator for tetracycline hydrochloride degradation in water

The advanced oxidation process based on hydrogen peroxide (H2O2) can effectively degrade tetracycline hydrochloride (TC). The key to activating H2O2 for the degradation of organic pollutants lies in the exploration of efficient and cost-effective catalysts. Natural coal gangue (CG), a byproduct of coal mining, holds potential for use in catalytic oxidation of pollutants. Zeolitic imidazolate framework-67 (ZIF-67) is commonly employed to activate sulfate systems, serving as a highly efficient Co-based heterogeneous catalyst that promotes the generation of strong oxidation species. However, there has been no relevant research on using CG to load ZIF-67 for the activation of H2O2 in pollutant degradation. In this study, ZIF-67/CG catalysts were prepared, with ZIF-67 and CG serving as precursors for the highly efficient activation of H2O2. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) confirmed that ZIF-67/CG possesses a favorable ability to activate H2O2. The results revealed that the degradation efficiency of TC in the ZIF-67/CG/H2O2 system reached 82.8% within 60 minutes. Radical quenching experiments, electron paramagnetic resonance (EPR) analysis, and an analysis of the degradation mechanism identified that ･OH and 1O2 played major roles in TC degradation.

Highly efficient recovery of Zn (II) from zinc-containing wastewater by tourmaline tailings geopolymers to in-situ construct nanoscale ZnS for the photodegradation of tetracycline hydrochloride

While treating zinc-containing wastewater, recovering zinc for reuse as a secondary resource has significant environmental and economic benefits. Herein, based on the alkali-activated tourmaline tailings geopolymers (TTG) after adsorption of zinc ions (Zn (II)), a series of new composites with in-situ construction ZnS nanoparticles on TTG (ZnS/TTG) were synthesized, and used as photocatalysts for the photodegradation of tetracycline hydrochloride (TCH) in solution. Specifically, ZnS nanoparticles were uniformly and stably distributed in the layered structure of TTG, interweaving with each other to generate an interfacial electric field, which could induce more photocarrier generation. Meanwhile, TTG acted as an electron acceptor to accelerate the electron transfer at the interface, thus enhancing the photodegradation activity for TCH. The active radical quenching experiments combined with the ESR indicated that the active species produced during the photocatalytic degradation of TCH by ZnS/TTG composites were •O2− and photogenerated h+. When the initial concentration of Zn (II) was 60 mg/L, the synthesized 60-ZnS/TTG composites (0.5 g/L) reached 91.53% degradation efficiency of TCH (10 mg/L) at pH = 6. Furthermore, the possible pathways and mechanism of 60-ZnS/TTG composites photodegraded TCH were revealed with the aid of degraded intermediates. This report not only proposed valuable references for reusing heavy metal ions and removing TCH from wastewater, but also provided promising ideas for realizing the conversion of used adsorbents into high-efficiency photocatalysts.

Catalytic activity and mechanism of F- and Cl-doped graphene for peroxymonosulfate activation to remove tetracycline hydrochloride.

Highly active catalysts with salt and acid/alkali resistance are desired in peroxymonosulfate (PMS) activation processes and marine environment applications. F- and Cl-doped graphene (F-GN and Cl-GN) were prepared via electronegative and atom radius adjustment for tetracycline hydrochloride (TCH) pollution removal to satisfy these requirements. The introduction of special F and Cl functionalities into graphene exhibits superior electron transfer properties for PMS activation, considering the experimental and density functional theory (DFT) calculation results. The TCH degradation efficiency reached up to 80% under various pH and salt disturbance conditions with F-GN and Cl-GN. Cl-GN exhibited an activity superior to F-GN due to the higher electron polarization effect of C atoms adjacent to Cl atoms. The presence of more positive charged C sites in Cl-GN (around Cl doping) is more favorable for PMS attachment and sequence radical generation than F-GN. In addition, the main active species functionalized during reaction included ·OH and SO4-·, and the stability of F-GN and Cl-GN was confirmed to be over 60% by recycle test. Final research results provide an effective strategy for designing and preparing PMS activators resistant to salt, acid, and alkali, thereby expanding their application potential.

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.

BiVO4 photoanode modified with FeOOH cocatalyst for visible-light-driven photoelectrocatalytic degradation of organic pollutants

Photoelectrocatalytic (PEC) could effectively and gently treat wastewater. Nonetheless, catalysts face the pronounced tendency of sluggish photogenerated carrier transfer and carrier recombination. In this paper, we herein fabricate FeOOH/BiVO4 photoanode through the incorporation of a cocatalyst FeOOH onto the BiVO4 surface. This modified photoanode demonstrated improved performance when coupled with peroxomonosulfate (PMS) for the purpose of oxidizing tetracycline hydrochloride (TCH) within the PEC system. In the presence of 0.3 mM PMS, the degradation efficiency of TCH increased from 65 % to 88 % within 60 min. The effects of PMS concentration, applied voltage and TCH concentration on the decomposition were studied in detail. Through free radical scavenging experiments, it was found that SO4•-, h+ and ·OH played an important role in TCH degradation. In addition, the FeOOH/BiVO4 with PMS activation in the PEC system also could be capable of dealing with some more organic pollutants (antibiotics and dyes) and achieving good degradation effect. More importantly, TCH degradation rate by FeOOH/BiVO4 photoanode is still over 80 % after five cycles of reuse. This work provides a promising approach for the synthesis of novel photoanodes in the PEC systems with excellent PEC properties in removing environmental pollutants.

Dual electron microregion with oxygen vacancy of Fe0.8La/MCM-48 in bridging peracetic acid and ozonation: Taking the pathway of free radical or nonradical generation?

Efficient tetracycline hydrochloride (TCH) degradation and interface reaction mechanism were investigated by constructing nonradical pathways in heterogeneous peracetic acid coupling with ozonation (O3/PAA) process. Ball-milling assisted Fe–La anchoring MCM-48 catalysts with dual electron microregion was designed to trigger 1O2-dominated non-radical for strong immunity to environment interference. Results exhibited that 83.4% degradation efficiency of TCH was achieved by Fe0.8La/MCM-48/O3/PAA system in only 2 min and 94% TCH was degraded in a 12-hour continuous flow experiment. La with oxygen vacancy regulated the local atomic environment and electron structure of Fe sites, which could initiate peracetic acid activation to promote 1O2 production by surface adsorbed atomic oxygen (*Oad) reaction and this process overcame a lower reaction energy barrier than the binding of surface *Oad to O3. This work offers a reasonable interpretation for Fe–La synergy for inducing non-free radical route, which furnishes theoretical support and practical application for heterogeneous O3/PAA.

Construction of Z‐scheme 1T/2H‐MoS2/CdS for improving photocatalytic degradation of antibiotic residues

Abstract1T/2H‐MoS2/CdS composite was effectively prepared by a two‐step hydrothermal method, which greatly improved the photocatalytic degradation efficiency of tetracycline hydrochloride and photocatalytic cycle stability compared with pristine 1T/2H‐MoS2. The highest photodegradation efficiency of 70.8% is achieved when the molar ratio of 1T/2H‐MoS2 to cadmium sulfide is 1:4. The capture experiment indicates that hydroxyl radical (⋅OH) and superoxide radical (⋅O2−) play a role in the photocatalytic degradation process. A Z‐type heterojunction may be formed on the 1T/2H‐MoS2/CdS composite based on a series of analyses, which improves the photocatalytic performance effectively via expanding the range of light response and promoting the separation of photogenerated electrons and holes. This work provides an alternative to constructing novel Z‐scheme photocatalysts with high performance in the absence of noble metals.

Rapid degradation of high-concentration antibiotic via heterogeneous photocatalysis coupling Fenton-like oxidation with MIL-53(Fe) under visible light irradiation

The photocatalytic technology based on Metal-Organic Frameworks (MOFs) has shown promising applications in the field of antibiotic pollution control. However, it still faces challenges in efficiently removing high-concentration antibiotic wastewater. A typical Fe-containing MOF, MIL-53(Fe), was successfully synthesized and demonstrated efficient photocatalytic activity under visible light irradiation for high-concentrations of tetracycline hydrochloride (TCH). However, the bare MIL-53(Fe) exhibited unsatisfactory photocatalytic performance. To overcome the low degradation efficiency resulting from the rapid recombination of light-induced electron-hole pairs, H2O2 was introduced as an external electron acceptor to establish a synergistic Fenton-like system to couple with the photocatalysis process. The results showed that in the MIL-53(Fe)/H2O2/Vis system, 99% of 1 g/L TCH was degraded within 80 min, while the degradation efficiency of the MIL-53(Fe)/Vis process was only 4.89% under identical conditions. The degradation mechanism of the coupling system was performed by radical scavenging experiments and Electron Spin Resonance characterization. The results indicated that ·OH was the dominant radical in the coupled reaction, and ·O2- and h+ also played a role in this system. The significant improvement in TCH degradation efficiency during the coupling process was attributed to the following three factors: (1) In the coupling reaction process, photo-generated electrons can stimulate H2O2 to form ·OH radicals, inhibiting the recombination of photo-generated electrons and holes, improving the efficiency of the photocatalytic reaction. (2) FeIII in MIL-53(Fe) can be excited by photo-generated electrons and converted to FeII, which then stimulates H2O2 to form ·OH radicals. (3) FeIII in MIL-53(Fe) can convert with FeII, stimulate H2O2 to form ·OH radicals, and participate in the degradation reaction. In addition, the reusability and stability of the MIL-53(Fe) photocatalyst in the coupled system, as well as the impact of operational parameters, were systematically studied. This work demonstrates a feasible strategy for environmental remediation by enhancing the efficiency of MIL-53(Fe) in photocatalytic Fenton-like systems, thereby providing a viable approach for the treatment of high-concentration antibiotic wastewater.

Design of magnetically separable double Z-scheme Ag3PO4/Fe3O4/MoS2 heterojunction with enhanced photocatalytic degradation of antibiotics under visible light irradiation

Photocatalysis is a promising technology in treating antibiotic wastewater. However, the rapid recombination of photogenerated electron-hole pairs and the loss of photocatalysts make its practical application challenging. To address these issues, a double Z-scheme heterojunction of magnetically separable Ag3PO4/Fe3O4/MoS2 photocatalyst is designed and applied for the photocatalytic degradation of tetracycline hydrochloride (TCH). The degradation efficiency of TCH by Ag3PO4/Fe3O4/MoS2 can achieve 99.0 % within 7.5 min under visible light irradiation, which is still above 91.3 % after 7 cycles. The excellent photocatalytic performance is attributed to the enhanced carrier life by constructing the double Z-scheme heterostructure in Ag3PO4/Fe3O4/MoS2. Mechanistic study indicates that •O2−, •OH, and h+ radicals are generated during the photocatalytic degradation. Combining experimental and theoretical calculations, two main degradation pathways are proposed, and the toxicity of the degradation system is significantly reduced. This study provides fresh insights into the photocatalytic degradation of refractory antibiotics by constructing magnetically separable Ag3PO4/Fe3O4/MoS2 heterojunction.

Cerium/sulfur co-doped spinel iron-cobalt oxide@carbon interconnected mesh networks as superior peroxymonosulfate activator for tetracycline degradation

Transition metal spinel oxides have potential applications in activating peroxymonosulfate (PMS) to generate reactive substances for degrading organics in polluted water. However, many catalytic materials have low efficiency, indicating the need for advancements in material design. In this study, we present the one-step fabrication of Ce, S-codoped spinel iron-cobalt oxide@carbon (Ce-FeCo2O4@SxC) with interconnected mesh networks for efficient PMS activation in degrading tetracycline hydrochloride (TCH). Among the Ce-FeCo2O4@SxC samples, Ce-FeCo2O4@S1.5C demonstrates the highest catalytic performance, achieving a TCH degradation efficiency of 97.2 % in 30 min. Moreover, the catalytic system also exhibits anti-interference abilities against various anions and shows universality in degrading organic pollutants. Characterization and experimental tests confirm the co-existence of radical (SO4•−, •OH and O2•−) and non-radical pathways (1O2 and direct electron transfer), with 1O2 identified as the primary reactive species. Three plausible pathways for TCH removal are proposed based on detected intermediate products. Toxicity evaluation reveals a significant reduction in the toxicity of the original TCH solution during the degradation process with the PMS activator. This study introduces a simple yet effective co-doping strategy to enhance the catalytic properties of spinel oxides for PMS activation in degrading organic contaminants in aquatic environments.

Efficient photocatalytic degradation of tetracycline hydrochloride by Cu2O/BiVO4 p-n heterostructure

Star-like BiVO4 and Cu2O nanocubes were prepared by hydrothermal method and chemical reduction, respectively, and Cu2O/BiVO4 p-n heterojunction with different mass ratios of Cu2O to BiVO4 (3:1, 1:1, 1:3) were synthesized via facile physical mixing. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of the Cu2O/BiVO4 composites was evaluated by degradation of tetracycline hydrochloride (TC) under simulated solar illumination. Owing to the fast charge transfer between n-type BiVO4 and p-type Cu2O, Cu2O/BiVO4 composites exhibited superior photocatalytic activity. When the mass ratio of Cu2O to BiVO4 was 1:3, the highest degradation efficiency of TC reached 78.9% within 24 min.

Carbon based cobalt titanate perovskite nanocomposite: Synthesis, characterization, and excellent visible light driven photocatalytic performance

Titanium-based perovskite oxides are the promising photocatalysts for an efficient degradation of organic pollutants. However, charge carriers recombination and wide band gap energy are still the main challenges in their visible-light-driven photocatalytic applications of Titanate perovskites, ATiO3. The immobilization of Titanium-based perovskites on a carbonaceous substrate such as nitrogen-rich carbon nitride, can be considered as an excellent option for enhancing photocatalytic performance. Here, the CoTiO3/C3N5 nanocomposite was synthesized by simple reflux method and used for photocatalytic degradation of three organic pollutants including methylene blue (MB), tetracycline hydrochloride (TC), and bisphenol A (BPA). The results indicated that the photocatalytic activity of the CoTiO3 perovskite was considerably improved by introducing C3N5 nanosheets and fabricating CoTP/C3N5 nanocomposite. The crystalline structure of CoTiO3/C3N5 (CoTP/C3N5) nanocomposites was confirmed successfully by XRD analysis. The specific surface area of the synthesized CoTP/C3N5 nanocomposite was 8.15 m2/g calculated by N2 adsorption–desorption technology. In the 60th minute of the photocatalytic process, the degradation efficiency of MB, TC, and BPA by CoTP/C3N5 were obtained as 98.70, 60.33, and 92.90 %, respectively, which were higher than pristine CoTiO3 nanorods and C3N5 nanosheets. Electrochemical impedance analysis shows that the CoTP/C3N5 nanocomposite has good electrochemical performance. The improvement photocatalytic activity CoTP/C3N5 can be attributed to the suppressing the recombination of photogenerated electrons and holes and good electrochemical performance with high electron transfer capability. The results achieved from UV–Visible Diffused Reflectance Spectroscopy (DRS), mott-schottky measurements and the photocatalytic degradation experiments in the presence of scavengers confirmed the significantly accelerating the Z-scheme charge transfer mechanism where photoexcited carriers can migrate between CoTiO3 perovskite and C3N5 nanosheets.