Removal Of Tetracycline Hydrochloride Research Articles

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.

Synergistic Engineering of Energy Band Alignment and Interfacial Electric Field Distribution over Bi-bismuth-Based Hetero-nanofibers for Boosting Visible-Light-Driven Photocatalytic Ammonia Synthesis and Antibiotic Removal.

Synergistic engineering of energy band alignment and interfacial electric field distribution is essential for photocatalyst design but is still challenging because of the limitation on refined regulation in the nanoscale. This study addresses the issue by employing surface modification and thermal-induced phase transformation in Bi2MoO6/BixOyIz hetero-nanofiber frameworks. The energy band alignment switches from a type-II interface to a Z-scheme contact with stronger redox potentials and inhibited electron traps, and the optimized built-in electric field distribution could be reached based on experimental and theoretical investigations. The engineered hetero-nanofibers exhibit outstanding visible-light-driven photocatalytic nitrogen reduction activity (605 μmol/g/h) and tetracycline hydrochloride removal rate (81.5% within 30 min), ranking them among the top-performing bismuth series materials. Furthermore, the photocatalysts show promise in activating advanced oxidants for efficient organic pollutant degradation. Moreover, the Bi2MoO6/Bi5O7I hetero-nanofibers possess good recycling stability owing to their three-dimensional network structure. This research offers valuable insights into heterojunction design for environmental remediation and industrial applications.

Synergistic enhancement of N, S co-modified biochar for removal of tetracycline hydrochloride from aqueous solution: Tunable micro-mesoporosity and chemisorption sites

The misuse of tetracycline hydrochloride (TCH) antibiotics has caused irreversible hazards to ecosystem. In this study, a series of porous biochar with tunable micro-mesoporosity and chemisorption sites are designed by cleverly exploiting the pyrolysis properties of active agents in various temperature regions. Benefiting from the existence of more pore structures matching the adsorbate while exposing more chemisorption sites, the maximum adsorption capacity (Qm) of NSC-1.0 for TCH is up to 1480.1 mg g−1 at 303 K. A combination of model fitting, post characterization and density functional theory (DFT) calculations confirms that the adsorption process involves the pore filling, the formation of non-covalent bonds (weak hydrogen bond, π-π stacking, electrostatic interaction) and ligand covalent bonding (Lewis acid-base interaction). The Qm is positively correlated with the volume of pore size greater than 1 nm (R2 = 0.9879), indicating that the pore filling effect is a decisive factor for adsorption performance. Post-characterization directly demonstrates that weak hydrogen bonding and π-π stacking are pivotal physical interactions for adsorption. DFT calculations show that partial N, S species and oxygen-containing functional groups can significantly reduce the adsorption energy of intrinsic graphene, especially the chemisorption sites of pyrrolic N (N5) and thiophene S (S5) containing lone-pair electrons. Furthermore, the competitiveness of NSC-1.0 is revealed in practical evaluation, including cation strength, regenerability, actual water source and fixed-bed column. This study not only contributes new insights to synergistically enhance the removal of macromolecular antibiotics by coupling matchable pore sizes and chemisorption sites, but also develops theoretical support for the fabrication of such efficient adsorbents.

Synthesis of Cu2+-doped magnetic ZnFe2O4 for catalyzing PMS to remove tetracycline hydrochloride

To address the limited catalytic activity of ZnFe2O4 in advanced oxidation process (AOP), Cu2+-doped ZnFe2O4 (Cu0.1Zn0.9Fe2O4) was synthesized using a simple one-pot hydrothermal method. Comprehensive characterization tests indicated that Cu2+ ions were doped into the lattice of ZnFe2O4 without changing the crystal structure. The introduction of Cu2+ ions made the sample highly ferromagnetic, with a specific magnetization of 25.7 emu/g. Cu0.1Zn0.9Fe2O4 was employed to catalyze the degradation of tetracycline hydrochloride (TCH). Systematic experiments indicate that the highest TCH removal reached 96.12 %, which was 40 % higher than that of ZnFe2O4. Coexisting inorganic anions in solution had very limited impact on the catalytic performance of Cu0.1Zn0.9Fe2O4. And after 5 cycles, the removal rate of TCH remained 71.06 %. ROS quenching tests suggest that 1O2 and O2·- played a dominant role in the AOP reaction.

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.

Zirconium‐Pentacarboxylate Frameworks with Coexisted 4‐ and 9‐Connected Zr6 Clusters for Detection and Removal of Tetracycline Hydrochloride

Zirconium‐Pentacarboxylate Frameworks with Coexisted 4‐ and 9‐Connected Zr6 Clusters for Detection and Removal of Tetracycline Hydrochloride

Boosting solar-light photocatalytic activity of Ni2P-decorated ZnCr2O4 nanofibers for H2 evolution and tetracycline elimination

Photocatalysis is a promising route to convert solar light into chemical energy for H2 evolution and pollutants degradation. Hence, Ni2P decorated ZnCr2O4 (Ni2P/ZnCr2O4) nanofibers were prepared for boosting solar-light induced water splitting and tetracycline hydrochloride (TCH) degradation. For comparison to ZnCr2O4 nanofibers, Ni2P/ZnCr2O4 composites exhibited the better photocatalytic activities for water splitting and TCH removal. Owing to the co-catalytic effect of Ni2P for the efficient photon capture, the charge carriers were rapidly separated and migrated at the interface between Ni2P and oxygen-defected ZnCr2O4. H2 evolution rate of optimal C–Ni2P/ZnCr2O4 with a nominal Ni2P content of 9.0 wt% was 575.89 μmol g−1 h−1, and its apparent quantum yield at 420 nm was 15.25 %, while its H2 evolution decreased from 2815.13 to 2602.51 μmol g−1 after fifth cycle. In addition, the removal efficiency of C–Ni2P/ZnCr2O4 was 93.68 % within 90 min, and declined to 88.76 % after five cycles for solar-light driven degradation of 50 mg L−1 TCH solution. The deactivation of C–Ni2P/ZnCr2O4 was due to the photo-corrosion for the change in valence states of compositions.

Facile hydrothermal synthesis and continuously improved sonophotocatalytic performance of PO4-doped Bi2WO6 nanoplates

The doping of ionic group composed of various atoms can play a great role in regulating electronic structure, optimizing light absorption capacity, and enhancing the catalytic performance of semiconductor catalysts. Herein, we took a urea-precipitate assisting hydrothermal route for preparing PO4-doped Bi2WO6 nanoplates and discussed the effect of the ionic group doping on the sonophotocatalytic performance toward the degradation of pollutant. The result of the X-ray photoelectron spectrometer (XPS) measurements revealed that abundant oxygen vacancies were formed in PO4-doped Bi2WO6 owing to the incorporation of the ionic group, which would contribute to the regulation of electronic structure and activated carriers’ migration rate. The sonophotocatalytic activity toward the removal of tetracycline hydrochloride (TCH) was investigated under visible-light coupling with ultrasonic irradiation. The results showed that PO4-doped Bi2WO6 nanoplates possessed higher sonophotocatalytic degradation rate than pure Bi2WO6. More interestingly, the TCH removal efficiency was continuously improved over PO4-doped Bi2WO6 nanoplates with the assistance of the sulfate radical-mediated technique. Based on the comprehensive discussion and analysis, a possible enhancement mechanism of the sonophotocatalytic behavior was proposed for PO4-doped Bi2WO6 nanoplates catalyst in the presence of peroxymonosulfate.

Synthesis of Fe-doped sludge biochar from Fenton sludge for efficient activation of peroxymonosulfate in tetracycline hydrochloride degradation

Traditional sludge treatment methods have problems in terms of environmental safety and cost-effectiveness. In this study, we followed the principle of "waste for waste" to synthesize magnetic sludge biochar (FSBC800) from biochemical sludge and Fenton sludge to activate persulfate (PMS) to remove persistent pollutants. Tetracycline hydrochloride (TC-HCl) was degraded up to 90.9% by FSBC800 using an active PMS system in just 30 minutes. This removal rate is higher than that of Fenton sludge biochar and biochemical sludge biochar by 2.7 and 1.8 times, respectively. The self-contained Fe in Fenton sludge formed evenly distributed Fe3O4 particles, while the biochemical sludge provided a large number of oxygen-containing functional groups, which increased the reactive active sites of FSBC800 and improved the catalytic performance. The dominant role of SO₄•⁻, •OH, and ¹O₂ in the degradation of TC-HCl was demonstrated by the identification of reactive oxygen species and electron paramagnetic resonance (EPR) analysis. By examining the intermediates, a potential TC-HCl degradation pathway was postulated. The catalyst has good reusability and practical application, and the removal of TC-HCl was still 84.8% after four replicated experiments. This study establishes a cost-effective, efficient, and recyclable biochar-based catalyst for water remediation, and at the same realizes resourceful utilization of sludge.

Enhanced degradation of tetracycline hydrochloride by microwave-activated sulfites: Influencing factors and mechanisms

Sulfite (SO32−) has garnered widespread attention for its ability to produce free radicals and environmentally friendly properties. In this work, the mechanism and feasibility of the microwave (MW) activated sulfite system for the removal of tetracycline hydrochloride (TCH) were investigated. The removal efficiency, reaction kinetics, and influencing factors of the MW/SO32− were explored. The identification of active substances and the reaction mechanism of the MW/SO32− system were further analyzed. The results showed that MW could activate sulfite effectively and the reaction process followed the pseudo-first-order kinetic. MW/SO32− achieved a 97.8 % degradation of TCH within 15 min. The influencing factors experiments showed that increasing the initial pH promoted the degradation of TCH. According to the results of EPR and free radical quenching experiments, the degradation of TCH by the MW/SO32− system had both free radical (SO3·−, SO5·−, SO4·−, and O2·−) and non-free radical pathway (1O2) reactions. The degradation pathways of TCH mainly included hydroxylation, removal reaction, ring-opening reaction, and oxidation reaction. Evaluation with the T.E.S.T system found that the ecological risk of TCH was reduced after MW/SO32− treatment. The use of microwaves as sulfite activation method was shown to be a new alternative to promote the rapid degradation of emerging organic pollutants.

Bi/BiVO4 tailoring molecular oxygen activation for SPR-promoted photocatalytic contaminant removal

In recent years, photocatalytic technology has been gained widespread attention in contaminants removal due to its green, low-carbon, sustainable properties. Bismuth vanadate (BiVO4) with decahedral shapes has emerged as a promising photocatalyst with unique photoinduced charges directional transfer. In this study, a simple wet chemical reduction method was used to load stable Bi0 nanoparticles in situ on the surface of decahedral BiVO4 to enhance the charges movement for molecular oxygen activation and tetracycline photodegradation. The formed Bi0 nanoparticles induced abundant oxygen vacancy defect states and surface plasmon resonance effects on BiVO4 nanoparticles surface. In aid of the special function of a surface heterojunction, decahedral BiVO4 can be photoexcited to produce more photogenerated carriers, and its separation efficiency is greatly improved, thus enhancing both the oxidative activity and photocatalytic activity. In the photocatalytic degradation process, superoxide radicals (∙O2−) showed the most significant contribution, and singlet oxygen (1O2) played junior role in tetracycline hydrochloride (TC) removal. 1O2 is obtained by ∙O2− and hole energy conversion, and some of it is produced by tetracycline photodecomposition under alkaline conditions. The BBV0.4 photocatalytic system has the best catalytic activity under weakly alkaline conditions, and the synergistic effect of photocatalysis and photodecomposition greatly improves the mineralization rate of TC. The large numbers of ∙O2− and 1O2 reactive oxygen species produced by BBV0.4 activation of oxygen play a crucial role in the photodegradation of TC via demethylation, deoxidation, deamination, ring-opening, and carbonylation to complete mineralization. This work studies in depth the change in the decahedral BiVO4 photocatalytic mechanism caused by the in situ introduce of bismuth metal, providing an efficient and environmentally friendly reference method for the rapid removal of tetracycline hydrochloride under alkaline conditions.

Puissant synergistic effect between g-C3N4 and MIL-100(Fe) for highly stable enhanced activation of H2O2 to degrade antibiotic tetracycline hydrochloride

The release of antibiotics in the environment has raised concerns about ecological damage and human health. As a promising technology, Fenton-like processes have been extensively studied to degrade pollutants in water and achieve rapid and efficient removal. Composites of metal-organic frameworks (MOFs) and graphitic carbon nitride (g-C3N4) have shown excellent performance in Fenton-like processes as a potent combination. However, there is a lack of similar studies to confirm their outstanding catalytic performance and stability in catalyzing the H2O2 process. Therefore, to complete the research in this field and to explore the efficient removal of antibiotics, composites of g-C3N4 and MIL-100(Fe) (CNMIL-x) were fabricated by post-synthesis for highly efficient H2O2 activation to remove tetracycline hydrochloride (TC-HCl). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) show that the characteristic morphology and peaks of g-C3N4 and MIL-100(Fe) varied according to the mass ratio between them. According to X-ray photoelectron spectroscopy (XPS), Fe is primarily in the Fe(Ⅲ) state. Besides, CNMIL-1.5 shows a SBET value of 598.46 m2·g−1, a Vpore of 0.42 cm3·g−1, and a pore size of 7.31 nm, which are significantly enhanced compared with g-C3N4. During TC-HCl degradation, the degradation rate of CNMIL-1.5 (0.02772 min−1) is 9.1 and 1.8 times faster compared to that of g-C3N4 and MIL-100(Fe), respectively. Furthermore, the excellent stability of CNMIL-1.5 are demonstrated by the quintuple cyclic experiments and characterization. A possible degradation mechanism dominated by •OH as well as a relative pathway of TC-HCl removal are proposed.

Magnetic CuFe2O4 nanoparticles immobilized on mesoporous alumina as highly efficient peroxymonosulfate activator for enhanced degradation of tetracycline hydrochloride

Nanoscaled magnetic copper ferrite (CuFe2O4) is widely used as a peroxymonosulfate (PMS) activator but suffers from agglomeration owing to its inherent magnetic properties and high surface energy. In this work, spinel structured CuFe2O4 anchored on mesoporous alumina (denoted as CFO@AO) were synthesized, characterized, and applied as a PMS activator for the removal of tetracycline hydrochloride (TC·HCl). Approximately 97.5 % of TC·HCl was decomposed within 10 min in 30 %–CFO@AO (0.2 g/L)/PMS (0.3 g/L) system, and the corresponding kinetic rate constant of 30 %–CFO@AO/PMS (0.417 min−1) was around 1.57 times higher than that of CuFe2O4/PMS (0.266 min−1), which indicating that the existence of synergistic catalysis between CuFe2O4 and Al2O3 enhanced the degradation of TC·HCl. Moreover, nano-sized CuFe2O4 were successfully anchored on the surface of Al2O3 because of FeOAl bond, which could account for the enhanced catalytic activity, superior pH flexibility, and high chemical stability and reusability of 30 %–CFO@AO. Quenching experimentals, electron paramagnetic resonance, and methyl phenyl sulfoxide (PMSO) chemical probe assays confirmed that both radical oxidation (OH) and non-radical oxidation (1O2 and Fe(IV)O) were proposed in the developed CFO@AO/PMS system, and OH played a key role in the process. Meanwhile, the PMS activation mechanism by CFO@AO composite was also analyzed based on the results of adsorption energy, which was calculated via DFT. Based on UPLC–MS technique, a possible degradation pathway for TC·HCl destruction in 30 %–CFO@AO/PMS system was proposed. The toxicity assessment showed that the catalytic degradation of TC·HCl in 30 %–CFO@AO/PMS system reduced the toxicity of most of degradation intermediates. Present work proved that CuFe2O4@Al2O3 composite is an efficient, environment-friendly, and recyclable heterogeneous catalyst for practical wastewater treatment via PMS activation.

Adsorption and degradation of tetracycline hydrochloride in aqueous solutions using activated carbon with Fe/Ag nanoparticles

In this study, a new adsorbent denoted as nAg/nZVI/AC was developed using activated carbon (AC) loaded with nanosized zero-valent iron (nZVI) and nanosilver (nAg). Then, the adsorption and degradation of tetracycline hydrochloride (TCH) in aqueous solutions using nAg/nZVI/AC was examined. At pH 3.8, the adsorbed amount of TCH on nAg/nZVI/AC was 191.18 mg/g, which is 78.95 mg/g higher than that adsorbed on the pristine AC support. The adsorption process could be explained adequately using the Freundlich (R2 = 0.9641) and pseudo-second-order kinetic models (R2 = 0.9967). Thermodynamic analyses revealed that TCH removal is a spontaneous chemisorption-dominated process. Free-radical-quenching experiments and electron paramagnetic resonance spectroscopic studies revealed that hydroxyl (·OH) and superoxide (·O2−) radicals are the main species involved in the degradation of TCH. Finally, the intermediates generated during the degradation were examined using liquid chromatography-mass spectrometry, and possible deterioration pathways are proposed.

Interfacial Si–O–Zr bonds induced well dispersed zirconia on magnetic mesoporous silicas for enhanced tetracycline removal

Constructing recoverable materials with both high adsorption capacity and excellent photocatalytic performance towards antibiotics elimination is very meaningful and challenging in wastewater remediation. In this work, we demonstrate a simple interface engineering strategy to design well dispersed zirconia on core–shell structured magnetic mesoporous silica microspheres (MMS) for efficient removal of tetracycline hydrochloride (TC). With ultrahigh specific surface area (682.0 m2/g) and interfacial Si-O-Zr serving as active sites, the optimal sample (MMS-Zr10) exhibits enhanced TC adsorption capacity of 266.5 mg/ZrO2 g, which is 19.2-fold than that of pure ZrO2. Simultaneously, the photocatalytic degradation rate constant of TC over MMS-Zr10 in the presence of peroxydisulfate (PDS) is 12.5 times that of ZrO2 under visible light irradiation, which may be attributed to the enhanced light harvest capability and high charge separation efficiency facilitated by interfacial Zr–O–Si charge transfer channels. Furthermore, in consecutive adsorption cycles in both deionized (DI) water solution and actual wastewater, no obvious decline in TC removal % is observed. The TC adsorption is mainly governed by pore filling, hydrogen bonding and electrostatic interactions; whilst O2•−, h+, SO4•−, •OH and 1O2 species are responsible for enhanced photocatalytic degradation of TC.

Treatment of antibiotics in water by SO3H-modified Ti3C2 Mxene photocatalytic collaboration with g-C3N4

Due to inherent limitations such as high carrier recombination efficiency, limited active sites, and suboptimal utilization of visible light, graphite-like carbon nitride (g-C3N4) has constrained its widespread application in water treatment within photocatalytic systems. In addressing this issue, the present study employed acid etching and sonochemistry to fabricate a Ti3C2-SO3H/g-C3N4 (TiCSOHCN) composite photocatalyst for the removal of tetracycline hydrochloride (TC). The amalgamation of Ti3C2-SO3H (TiCSOH) with g-C3N4 engendered the establishment of a discernible Schottky barrier, facilitating an expedited electron transfer rate. Photocatalytic degradation experiments demonstrate that, compared to individual components, the TiCSOHCN composite photocatalyst exhibits significantly enhanced photocatalytic activity. The removal efficiency of TC reaches 75.42 % within 2 h, and even after five cycles of experimentation, the degradation efficiency remains close to 70 %, indicating excellent stability. The augmentation can be predominantly ascribed to the cooperative influence arising from the synergy between Ti3C2-SO3H and g-C3N4. The augmentation of visible light responsiveness in g-C3N4, achieved through its modification with TiCSOH, resulted in the mitigation of photoelectron-hole pair recombination, consequently leading to an amelioration in the photocatalytic efficacy of the TiCSOHCN composite catalyst. Intermediate species arising from the degradation of tetracycline were discerned utilizing LC-MS, and conjectures regarding plausible degradation pathways were postulated. Evaluations of the ecotoxicological impact of tetracycline and its intermediates indicated a progressive diminution in toxicity throughout the course of the photocatalytic degradation process. Furthermore, through free radical capture and EPR tests, it was confirmed that ·O2– and ·OH are the primary active species responsible for the photocatalytic degradation of TC, substantiating the proposed rational photocatalytic degradation mechanism. This research provides an innovative approach to developing high-performance and stable photocatalysts.

Magnetic MnFe2O4/ZIF-67 nanocomposites with high activation of peroxymonosulfate for the degradation of tetracycline hydrochloride in wastewater.

Advanced oxidation processes (AOPs) based on PMS have been used to degrade various refractory pollutants such as drugs, endocrine disruptors, dyes and perfluorinated compounds due to their wide application range, mild reaction conditions, fast reaction rate and simple operation. In this study, tetracycline hydrochloride (TCH) was degraded based on this method. Magnetic MnFe2O4/ZIF-67 nanocomposites were successfully prepared by a hydrothermal method, which combined the magnetic separation characteristics of MnFe2O4 with the high catalytic activity of ZIF-67 and were used to activate peroxymonosulfate (PMS) to efficiently degrade TCH. Satisfactory removal results were obtained with this simple and readily available material, with 82.6% of TCH removed in 15 min. The effect of different conditions on the degradation effect was investigated, and the optimal catalyst concentration and PMS concentration were determined to be 0.1 g L-1 and 0.2 g L-1, respectively, and all had good degradation effects at pH 5 to 10. XPS, impedance test and radical quenching experiments were used to investigate the degradation mechanism. The results showed that sulfate radical (SO4-˙) was the main active species in the degradation process. In addition, the catalyst has good cyclic stability, which provides a new idea for the removal of TCH in wastewater. It is worth mentioning that the catalyst also has good degradation property for other pollutants.

Insights into the solar-light activated adsorption-photocatalysis of ZnLaxBi2−xO4 heterojunctions for tetracycline hydrochloride removal

Metal oxides-based heterojunction fabrication is a promising strategy to eliminate antibiotics from wastewater via adsorption-photocatalysis. ZnLaxBi2−xO4 hybrids with various La/Bi molar ratios were fabricated for enhancing the adsorption-photocatalytic elimination of tetracycline hydrochloride (TCH). Oxygen-defected ZnLaxBi2−xO4 composites provided the sufficient sites for photon capture and pollutants adsorption. In addition, the tight p-n-p type interface among oxygen-defected La2O3, ZnO, and spinel ZnBi2O4 favored the rapid transfer and migration of photo-excited e-/h+ pairs, enlarging the visible light utilization. Hence, ZnLaxBi2−xO4 samples had the better adsorption-photocatalytic activity than ZnLa2O4 and ZnBi2O4 for TCH removal. Langmuir and second-order models well described the adsorption isotherms and kinetics of ZnLaxBi2−xO4 samples, respectively. The adsorption capacity of optimal ZnLa1.75Bi0.25O4 with a La/Bi molar ratio of 7:1 was 406.85 mg g−1, and its removal efficiency of 210 mg L−1 TCH solution was 98.04 % within 150 min. The change in valence states of surface compositions induced to the declined removal efficiency of ZnLa1.75Bi0.25O4 to 91.95 % after five cycle times.

Selective vanadium etching and in-situ formation of δ-Bi2O3 on m-BiVO4 with g-C3N4 nanosheets for photocatalytic degradation of antibiotic tetracycline

Antibiotics play a vital role in treating microbial illnesses, but their presence in water bodies is a global concern. Despite the potential of polymeric graphitic carbon nitrate (g-C3N4) as a photocatalyst for wastewater treatment, its effectiveness is hindered by a fast charge carrier recombination rate. To overcome this challenge, we have developed a novel approach involving the surface etching-oxidation technique to introduce δ-Bi2O3 onto m-BiVO4. Subsequently, the modified δ-Bi2O3/m-BiVO4 (BBV) was synergistically coupled with g-C3N4 (CN) to create a hybrid photocatalyst (BBVCN). The photocatalytic activity of BBVCN was evaluated using tetracycline hydrochloride (TC) as a model wastewater antibiotic pollutant, demonstrating a 92 % degradation of TC within a 1 h reaction time. Total organic carbon analysis demonstrated a TC removal efficiency of 76 %, indicating significant mineralization by BBVCN.

Efficient degradation of tetracycline hydrochloride by activated peroxymonosulfate with PdO/CuFe2O4/coal-bearing strata kaolinite composite

In this study, a 4%PdO/CuFe2O4/coal-bearing strata kaolinite (4%PdO/CFO/CK) composite was successfully prepared using a simple hydrothermal method and used as a catalyst for tetracycline hydrochloride (TCH) degradation in wastewater by activating peroxymonosulfate (PMS) in visible light. The synthesized catalyst was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis. The effects of different catalyst and PMS dosages, pH of the initial solution, and other key parameters on TCH removal were studied. The results showed that the TCH removal rate using the 4%PdO/CFO/CK + PMS + Vis system was as high as 91.96 % within 20 min at a pH of 4.0, catalyst dosage of 20 mg, and PMS dosage of 1.5 mL. In addition, the TCH removal rate remained >85 % after three cycles, thereby verifying the stability and reusability of the 4%PdO/CFO/CK composite. Finally, free radical capture experiments and electron paramagnetic resonance identified the reactive oxygen species involved in the degradation process as 1O2, •O2−, h+, •OH, and SO4•−, and we proposed a mechanism for TCH removal using the 4%PdO/CFO/CK + PMS + Vis system. Our findings provide a promising solution for removing TCH from wastewater using the 4%PdO/CFO/CK + PMS + Vis system.