Photodegradation Of Tetracycline Research Articles

A novel 0D/2D Z-scheme heterojunction Bi2Sn2O7/Bi4O7 for boosting tetracycline photodegradation: Insight from performance to mechanism

The slow migration and low separation efficiency of charge carriers inhibit the photocatalytic degradation of pollutants in water. Constructing heterojunction is an effective strategy to enhance photocatalytic performance. Herein, a novel Z-scheme Bi2Sn2O7/Bi4O7 (BOBSO) heterojunction was designed and synthesized for degrading typical antibiotics in water. The 0.2BOBSO heterojunction exhibits excellent photocatalytic performance, achieving a 97.97 % tetracycline degradation rate under visible light irradiation, significantly surpassing the individual materials Bi2Sn2O7 (75.93 %) and Bi4O7 (18.61 %). The composite photocatalyst shows excellent stability and strong adaptability to environmental factors. Compared to Bi2Sn2O7 and Bi4O7, 0.2BOBSO heterojunction possesses superior microstructure and photoelectrochemical properties confirmed by various characterizations. The electron transfer mechanism of Z-scheme heterojunction on the composite surface was proposed according to in-depth analyses using UV–vis, Mott-Schottky, and Electron Spin Resonance (ESR). The formation of Z-scheme heterojunction accelerates the migration of photogenerated charge carriers while maintaining the optimal redox ability of the materials. Furthermore, quenching experiments confirm that h+, O2−, and 1O2 are the main active species in the reaction system, with TC degraded via both radical and non-radical pathways. This study provides new insights into the design and construction of 0D/2D Z-scheme heterojunction photocatalysts.

Mesoporous I-doped-g-C3N4 with C Vacancies as Superior Visible-light-driven Photocatalyst for Removal of Tetracycline Antibiotic

The discovery of g-C3N4 (GCN) has attracted great attention for antibiotic pollutants from wastewater. Nonetheless, photocatalytic performance of GCN suffers from rapid recombination, limited surface area, and restricted under visible light irradiation. In this work, different concentrations of mesoporous I-doped GCN were synthesized. Mesoporous I-doped GCN with 0.50g of I dopant (GCN-I0.50) manage to photodegrade 99.8% of TC within 150min under visible light (λ > 420nm). The tetracycline (TC) antibiotic photodegradation rate increased by 2.64 times than that of parent GCN. It is proven that I-dopant and generation of C vacancy provides extra electrons to reconstruct the GCN network. This led to a stronger driving force in photo-oxidation photodegradation. The C vacancy also acts as a trap to prevent fast charge recombination. Subsequently, the substantial surface area and mesoporous nature of GCN-I0.50 (63.76 m2/g) facilitate the breakdown of a greater quantity of TC pollutants. In addition, the structural distortion of GCN-I0.50 has promoted n-π* transition, extended photoactivity to visible light region due to smaller band gap (2.45eV). The GCN-I0.50 photocatalyst significantly improved the TC photodegradation rate with good stability.

Boosting photocatalytic hydrogen generation and Photo-Destruction of Tetracycline by In-Situ oxygen vacancies ZnIn2S4

In this study, ZnIn2S4 with oxygen vacancies was fabricated using NaBH4-assisted hydrothermal method to enhance the photocatalytic activities. The generated ZIS and ZISVo-x samples exhibited microspherical nanosheet structure and it is proven that NaBH4 could enhance the amount of oxygen vacancies in ZnIn2S4 as confirmed by XPS analysis. Upon solar light irradiation, ZISVo-5 sample performed a fast photodegradation of tetracycline (TC) within 10 min and simultaneously exhibited a hydrogen evolution amount of ∼ 12 mmol (AQE = 6.07 at 420 nm), which is 2.75 times higher than that of pristine ZnIn2S4 (4.4 mmol). The degraded products of TC were further identified using LC-MS. The excellent photocatalytic HER performance was attributed to the optimum amount of oxygen vacancies in ZISVo-5 sample and the reactive oxygen species of •OH, O2•-, and 1O2 as confirmed by ESR analysis under light irradiation played a vital role for the rapid degradation of TC by ZISVo-5.

Synthesis and Characterization of CaO nanoparticles from Periwinkle shell for the Treatment of Tetracycline-contaminated Water by Adsorption and Photocatalyzed Degradation

Due to the ever-increasing discharge of antibiotic residues into different water bodies, there is a significant need to improve existing water treatment methods. In this study, we synthesized calcium oxide nanoparticles from periwinkle shells using the sol-gel method for applications in the adsorption and photodegradation of tetracycline from wastewater. The nanoparticles were characterized using FTIR, UV-Visble spectroscopy, XRD, SEM-EDX, TEM, BET and TGA/DTA. The nanostructure produced showed strong crystalline, optical, structural and surface properties. With an average crystallite size of 25 nm, particle size of 2.09 nm, BET surface area of 582.68 m2/g, specific surface area of 90.08 m2/g, bandgap of 4.8 eV and other properties that supported their functionality as adsorbent and photocatalyst for the removal of tetracycline residue from water. The adsorption experiment gave a maximum efficiency of about 80% while the photodegradation catalysed by the nanoparticles indicated efficiency up to 97%. Both adsorption and photodegradation showed strong dependency on pH, tetracycline concentration, catalyst load and concentration of KI. Response surface analysis and subsequent experimental validation indicated that degradation approaching 100% for tetracycline is feasible under optimum conditions involving concentration = 500 ppm, time = 50 min, catalyst load = 1.25 g and KI concentration = 0.25 M. Computational calculations gave results that are in good match with experimental data and further proved that the degradation is limited by adsorption and is majorly controlled by oxidation facilitated by O2*.

Amorphous titanium dioxide with synergistic effect of nitrogen doping and oxygen vacancies by photoexcited sol-gel preparation for enhanced photodegradation of tetracycline

In this paper, a novel N-doped amorphous titanium dioxide (N20AT-hν) photocatalyst was prepared by the sol–gel route in which the sol added with salicylaldehyde hydrazone undergoes gel after photoexcitation. Based on a systematic exploration of as-prepared catalysts, it is known that N20AT-hν sample has a particle size of 50–60 nm, a specific surface area of 294.699 m2 g−1, and which is doped with nitrogen elements and forms abundant oxygen vacancies (OVs). The photocatalytic degradation rate of N20AT-hν for 20 mg L−1 tetracycline solution reached 92.23 % after 60 min, and the rate exhibited a slight decrease of 8.68 % after five cycles. Reactive species trapping experiments and electron spin resonance techniques indicate that superoxide radicals and holes are instrumental in photocatalytic degradation. Possible mechanism of forming the active species through OVs mediated traps and electron transfer pathways has been proposed. Furthermore, the predictive evaluations suggest that the degradation of tetracycline solutions by N20AT-hν sample results in less harmful decomposition product.Benefiting from the environmental friendliness of preparation method and the superiority of elemental doping, N20AT-hν material with synergistic effects has great potential for environmental applications.

Harnessing light: advanced photodegradation of tetracycline using NH2-MIL-101(Cr)@ZIF-67 in water

Harnessing light: advanced photodegradation of tetracycline using NH2-MIL-101(Cr)@ZIF-67 in water

Understanding the potential of coal gangue as photocatalyst for antibiotic degradation: The role of abundant oxygen vacancies and electron-hole pairs

Coal gangue (CG) offers promising potential as a cost-effective photocatalyst for antibiotic degradation. However, current approaches do not emphasize the origin of its photocatalytic activity. This study investigates the photocatalytic activity of CG through a comparative analysis with one-pot aerobic/anaerobic calcinated CG. The potential application of CG as a photocatalyst for tetracycline (TC) decontamination in water was evaluated under dark and light. Characterization results identified anatase and kaolinite as the critical photosensitive minerals in CG. Batch removal experiments indicated that CG achieved up to 98 % TC removal at 1 g/L dosage, with most biotoxic intermediates reduced to below 0.9 mg L−1 Lethal Concentration 50 (LC50) of Fathead minnow (Pimephales promelas). Degradation pathways identified by density functional theory (DFT) and quantitative structure-activity relationship (QSAR) indicated that superoxide anion (⁎O2−) and electron-hole (e−-h+) pairs were predominant contributors to TC photodegradation. Theoretical calculations suggest that the oxygen vacancies on the CG surface can accelerate the production of ⁎O2−, while fast electron transport channels within surface hydroxyl groups facilitate e− and h+ separation. The findings of this research elucidate the origin of CG's photocatalytic activity and highlight the potential to serve as a photocatalyst for low-cost antibiotic removal, offering a promising solution for coal waste management and utilization.

Sustainable photodegradation of tetracycline by surface-functionalized carbon nitride: Mechanism insight and toxicity assessment

Here, we report the facile preparation of amino- and vacancies-abundant carbon nitride photocatalyst using acetone as a low-boiling-point solvent and describe its successful performance of environmental purification. As a demonstration of the notion, tetracycline (TC) antibiotic as an emerging aqueous contaminant has been used as a model substrate for assessing the photoactivity of the modified carbon nitride and clarifying its intrinsic mechanism. 96 % of TC can be photocatalytically removed within 30 min, accompanied by a discernible mitigation in ecotoxicological impact. Reactive species, including •OH, •O2-, and photogenerated holes, are considered the critical oxidants. Meanwhile, the possible intermediates and transformation pathways of TC degradation were investigated utilizing the LC-MS technique, the Fukui function, and the T.E.S.T. software. The comprehensive approach furnishes valuable insights for assessing the evolutionary dynamics of tetracycline in an advanced oxidation process (AOP). This study offers a sustainable, cost-effective, and eco-friendly approach to preparing carbon nitride material, which is believed to open an avenue for the facile design of heterogeneous environmental photocatalysts and to provide insights into the various environmental applications.

Enhanced self-biased photocatalytic fuel cell performance by dual-photoelectrode with novel graphene-based substrate for tetracycline photodegradation and electricity production

In this study, a graphene-based dual-photoelectrode photocatalytic fuel cell (PFC) system, incorporating n-type ZnO photoanode and p-type Cu2O photocathode, has been meticulously designed and fabricated to achieve concurrent organic pollutant decomposition and electricity production. The rGO-ZnO｜rGO-Cu2O PFC system displayed superior photoelectrocatalytic performance, surpassing the comparative FTO-based PFC system. Notably, it achieved power density of 22.23 μW cm−2 maximumly, tetracycline hydrochloride (TCH) degradation efficiency of 74.0 % within 120 min, and exhibited long-term stability. This enhanced performance can give the credit to the larger active areas generated by the in-situ growth of photocatalytic materials in layered microstructure of graphene films, as well as the rapid electron transfer within graphene films. This study underscores the potential application of graphene films as electrode substrate materials, and introduces a strategy for achieving the diversification and optimization of electrode substrate material selection, ultimately facilitating the development of more efficient PFC systems.

Zeolitic imidazolate framework-67/barium zirconate titanate nanocomposite, Part I: Synthesis, characterization, and boosted photocatalytic activity

Using BaTi0.85Zr0.15O3/ZIF-67 (BTZ/ZIF-67) nanocomposite, tetracycline (TC) was photodegraded. Characterization of the samples was carried out using a variety of techniques, including XRD, FESEM-EDS (Field Emission Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy), FT-IR (Fourier Transform Infra-Red), TEM (Transmission Electron Microscopy), BET (Brunauer-Emmett-Teller), BJH (Barrett-Joyner-Halenda), PL (Photoluminescence), TG-DTG (Thermogravimetry and Derivative Thermogravimetry), and UV–Vis DRS (Diffuse Reflectance Spectroscopy). BTZ/ZIF-67 nano-composites were synthesized using a one-step co-precipitation method. BTZ (30 %wt)/ZIF-67 showed the most impressive photocatalytic ability among the binary photocatalysts. Averaging the crystallite sizes of the nanocomposite samples identified by Scherrer and Williamson-Hall methods was 43.3 nm and 65.0 nm, respectively. The pHpzc values of samples of BTZ and BTZ (30 %wt)/ZIF-67 were approximately 6.7 and 10.0, respectively. Using the proposed method, we measured 357, 414, and 377 nm absorption edges for ZIF-67, BTZ, and BTZ (30 %wt)/ZIF-67 samples, which correspond to 3.47, 2.99, and 3.28 eV bandgap energies, respectively. The specific surface areas of BTZ, ZIF-67, and BTZ (30 %wt)/ZIF-67 nanocomposite are 122.15, 1218, and 1509 m2g−1, respectively. Under optimum conditions (0.8 g/L of the catalyst, CTC: 30 mg/L, and a pH 5), 89.5 % of total organic carbon (TOC) was removed within 180 min. Compared to BTZ photocatalyst, the BTZ (30 %wt)/ZIF-67 nanocomposite has a significantly larger surface area, thus enhancing photocatalytic activity. A synergistic effect was observed in the photodegradation of TC under Hg-lamp irradiation with the proposed BTZ/ZIF-67 composite. It is possible to alter the photocatalytic activity of the catalyst by changing the BTZ (30 %wt)/ZIF-67 ratio.

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.

Z-scheme heterojunction TNCoPc/BiOBr nanomicrospheres for efficient photodegradation of tetracycline and rhodamine B: Degradation performance, intrinsic mechanism and degradation pathway studies

The natural ecosystem has been significantly jeopardized due to the misuse of organic dyes and antibiotics. To treat organic wastewater safely and efficiently, this study synthesized a binary composite photocatalyst TNCoPc/BiOBr, using a solvothermal method that involved loading cobalt tetranitro phthalocyanine onto BiOBr. The results of the catalytic performance tests indicated that the composites exhibited the capacity to degrade rhodamine B and tetracycline hydrochloride by 97.75 % and 78.37 %, respectively. Moreover, the composite exhibited good cyclic stability. Subsequent analytical characterization confirmed the formation of a Z-scheme heterojunction, resulting in a synergistic effect. This Z-scheme heterojunction facilitated the capacity of photocatalyst to achieve enhanced light absorption, augmented photogenerated carrier separation efficiency, and augmented redox capacity. Additionally, theoretical calculations were employed to further elucidate the catalytic mechanism and synergistic effects. The results demonstrate that the Co-N4 sites are the active center of the TNCoPc and verify the contribution of nitro substitution to the photogenerated electron transfer mechanism on TNCoPc. Furthermore, a systematic degradation pathway was predicted and deduced based on Fukui indices and liquid chromatography-mass spectrometry data. This study presents a paradigm for the application of composite photocatalysts containing substituted phthalocyanines in the degradation of organic wastewater.

Performance and mechanism insights into S-doped superhydrophilic carbon nitride for photocatalytic hydrogen evolution and degradation

Carbon nitride (CN) photocatalyst possesses great potential in alleviating energy and environmental crisis, while the insufficient active sites exposure, limited light harvest and poor charge behavior, as well as inferior dispersibility in water limit its photocatalytic activity. In this research, a loose porous crimp S doped CN photocatalyst with superhydrophilicity was tailored via facile one-pot thermal-melting followed thermal induce copolymerization of urea with 2-mercaptonicotinic acid. The dope of 2-mercaptonicotinic acid leads to the significant enhancement of specific surface area, range/intensity of visible-light harvest and charge behavior, as well as hydrophilicity of CN. The photocatalytic hydrogen evolution rate achieves a remarkable improvement of 7.61 times compared to CN alone, reaching 88.14 μmol h−1. Additionally, the photodegradation of tetracycline is enhanced by approximately 3.96 times compared to pristine CN, resulting in a degradation efficiency of 90.5 %. Via active species capture tests, ESR, LC-MS, toxicity prediction and DFT calculations, the main active species, degradation pathway, intermediates toxicity and promoted mechanism of photocatalytic performance are explored. This study presents a straightforward and cost-effective approach to enhance the intrinsic activity of CN-based photocatalysts by simultaneously regulating their active sites exposure, light absorption and charge behavior for addressing environmental and energy concerns.

Highly efficient adsorption and visible-LEDs-driven photodegradation of tetracycline over novel and green-synthesized p-BiOI/n-Bi2WO6 heterojunctions

Preparing bismuth compounds-based heterojunctions with superior redox capability has emerged as a promising strategy for environmental remediation. Herein, p-BiOI/n-Bi2WO6 heterojunctions were successfully obtained via a novel, facile, and green solvothermal method. The heterojunctions were synthesized using different mass ratios (1:2, 1:1, and 2:1) of BiOI (BI) and Bi2WO6 (BW), with 1:1 as the best ratio, which was decorated with silver nanoparticles (Ag-NPs) and nitrogen-doped graphene (NG) applying green methodologies. The as-prepared BI/BW heterojunctions were characterized by several techniques, and their adsorption capacity and photodegradation activity toward tetracycline (TC) under 19 W visible LEDs illumination were investigated. The capacity of pure BI, BW and BI/BW heterojunctions for adsorbing TC ranged from 14 to 68 mg/g; among the heterojunctions, Ag/1BI/1BW showed the highest TC adsorption capacity, 35 mg/g. Moreover, the photocatalytic tests revealed that the Ag/1BI/1BW exhibited the highest catalytic performance, achieving a TC percentage degradation of 81 % within 120 min. The low nominal power consumption of the LED-based photoreactor (0.0475 kWh) was significantly lower than that reported in the literature for using Xe or Hg lamps. In addition, catalyst dosage, initial TC concentration, and solution pH were investigated, demonstrating that they play important role in TC photodegradation. Scavenger assays determined that the degradation of TC using Ag/1BI/1BW proceeds mainly via superoxide radicals and holes, which agrees with the carrier transfer mechanism postulated for this heterojunction. TOC analysis revealed that the efficiency of Ag/1BI/1BW was 63 %, and reuse tests confirmed its high performance even after three cycles. This research provides new insights into the design of high-performance heterojunctions for water treatment.

A novel 0D/3D Z-Scheme heterojunction ZnS/MIL-88(A) with significantly boosted photocatalytic activity toward tetracycline

Coupling two different photocatalytic materials to construct a heterojunction is a preferable strategy for obtaining the composite photocatalyst with high activity. Herein, a novel 0D/3D Z-scheme heterostructure ZnS/MIL-88(A) was constructed by anchoring 0D ZnS nanoparticles on the surface of the 3D MIL-88(A). The prepared ZnS/MIL-88(A) was characterized by using FT-IR, XRD, SEM, UV–vis and XPS. The photodegradation of tetracycline (TC) was conducted under the irradiation of visible light to evaluate the photocatalytic performance of ZnS/MIL-88(A). The creation of the Z-scheme heterostructure between ZnS and MIL-88(A) enables ZnS/MIL-88(A) to exhibit excellent visible-light absorption ability and dramatically boost separation and transfer of the photo-induced charge carriers. Compared with MIL-88(A), ZnS/MIL-88(A) shows prominently enhanced photocatalytic activity toward tetracycline, achieving a TC degradation rate of 94 %. The highest photodegradation rate constant (0.02083 min−1) of TC by ZnS/MIL-88(A) is 7.77 and 12.33 folds as large as those by MIL-88(A) and ZnS, respectively. After five cycles of reuse, ZnS/MIL-88(A) shows only a slightly decreased TC removal rate, presenting excellent photo-stability. Furthermore, the Z-scheme interfacial charge migration mode and the photocatalytic mechanism of ZnS/MIL-88(A) were discussed according to the band position as well as the identification result of the active species. The radicals ·O2− and ·OH generated in photocatalysis serve as major reactive species to decompose TC. This work provides a new way for designing efficient composite photocatalysts.

Synthesis of a novel flower-like Bi4Ti3O12/AgI Z-type heterojunction for efficient photocatalytic removal of tetracycline antibiotic and RhB

Novel Flowerlike Bi4Ti3O12/AgI (BTO/AgI) Z-type heterojunctions were fabricated via a straightforward in-situ precipitation method. Notably, BTO/AgI exhibited significantly improved photodegradation efficiency for tetracycline (TC) and Rhodamine B (RhB). The rate constants for RhB and TC photodegradation were approximately 20.8 and 2.9 times higher than those of BTO alone, respectively. Furthermore, the photocatalytic efficiency of the BTO/AgI heterojunction is 1.4 times higher than that of the mixture of the two individual photocatalysts, indicating a robust interaction between BTO and AgI. This enhancement in photocatalytic performance was mainly attributed to the effective separation of photogenerated carriers facilitated by the Z-scheme heterojunction, which can be demonstrated by the highest photocurrent density (∼0.307 μA·cm−2) of BTO/AgI, surpassing BTO (∼0.073 μA·cm−2) and AgI (∼0.161 μA·cm−2) by approximately 4.12 and 1.91 times, respectively. Furthermore, three plausible photodegradation pathways of tetracycline were proposed. This study introduces a novel approach for designing and synthesizing high-efficiency Z-scheme photocatalysts for the degradation of TC and RhB in wastewater.

Effects of coexisting nanomaterials on the photodegradation behavior and ecotoxicity of antibiotics in the aqueous

Nanomaterials (NPs) and antibiotics, as two emergent pollutants, forms a complex contamination through their interaction, potentially causing adverse effects on the organism. This study systematically examined the influence of two NPs (CuO NPs and carbon nanotubes, CNTs) on the photodegradation behavior of tetracycline (TC) and their combined toxic effects on Chlorella vulgaris. The results showed that CuO NPs significantly accelerated TC photodegradation compared to CNTs, increasing the TC photodegradation rate constant by187.6%. Electron spin resonance (ESR) indicated that under the coexistence of CuO NPs or CNTs, 1O2、O2•- and •OH were the main active species promoting TC photodegradation. Probe and quenching experiments confirmed the predominant role of O2•- and 1O2 in the presence of CuO NPs and CNTs. Additionally, three possible TC photodegradation pathways were proposed for the coexistence of CuO NPs and CNTs. In the Chlorella vulgaris growth inhibition experiment, the combined toxicity of CuO NPs or CNTs and TC was higher than that of individual substance, indicating significant synergistic effects, especially with the combination of CNTs and TC. This study provides a new perspective on accurately assessing the environmental behaviors and risks when NPs and antibiotics coexist.

Enhanced tetracycline degradation using UV/Fenton/titanium dioxide (TiO2) hybrid process

TiO2 was synthesized using neem leaf extract as soft bio template and Titanium (IV) isopropoxide (C12H28O4Ti) as a precursor. Morphological properties revealed well crystalline anatase phase of 19.8 nm size for the biotemplated TiO2 (B-TiO2) compared to 24.2 nm of the non-templated TiO2 (N-TiO2). TEM revealed a nano sheet-like structure for the B-TiO2 and it exhibited a larger SBET surface area (35.45 m2/g) and average pore diameter (5.74 nm) compared to the N-TiO2 (19.72 m2/g) and (2.028 nm) respectively. XPS results showed carbon peaks indicating small bio-carbon doping on the lattice of the TiO2, which can promote charge transfer upon light excitation during photocatalyst reactions. The results of the photoluminescence study indicate reduced PL intensity of the B-TiO2 which signifies the suppression of recombination of charge carriers or electron-hole pairs in the B-TiO2. The photocatalytic activity was assessed by the photodegradation of tetracycline (TC: 50 mg/L) under UV irradiation and the B-TiO2 was employed as a photocatalyst. In the absence of UV light, B-TiO2 catalyst slightly removed TC due to limited active species. However, the degradation of TC increases significantly due to the synergetic effect of the UV/Fenton/B-TiO2 hybrid system. Moreover, the biotemplate exposes the surface of the B-TiO2 which permits improved utilization of all surface-active sites. Quenching experiments were also performed via scavengers, results confirmed that hydroxyl radicals, superoxide radicals and electrons are the key reactive species in the TC degradation. The effects of influential parameters such as B-TiO2 dosage, TC concentration, pH, and Fe2+ to H2O2 molar ratio were also investigated, in addition, the catalyst is stable, as it achieved > 80 % TC degradation efficiency after five reuse cycles.

A novel barium zirconate titanate/Fe-MOF nanocomposite: Synthesis, characterization, and photocatalytic mechanism

The synthesis of a metal-organic framework (MOF) matrix of MIL-100 (Fe) loaded with BaTi0.85Zr0.15O3 (BTZ) nanoparticles (NPs) was achieved by an easy one-pot solvothermal procedure and encasing of BTZ NPs. X-ray diffraction (XRD), photoluminescence spectroscopy (PL), UV-Vis reflectance spectroscopy (DRS), Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and N2 adsorption-desorption were deployed for the characterization of the synthesized samples. The degradation efficiency for tetracycline (TC), among the photocatalytic BTZ/MIL-100(Fe) nanocomposites with varied BTZ percentages (10, 20, 30, and 40 wt% BTZ), revealed that (30 wt%), offered the best outcome. At 0.8 g L-1 of the catalyst, pH 9, 30 ppm TC solution, and 180 min irradiation time, as the optimal conditions, the degradation efficiency of TC molecules reached >90. Based on the study of some scavenging agents, the importance of the reactive species in TC photodegradation followed the trend of photogenerated e-, hydroxyl radicals, superoxide radicals, and photogenerated h+. TC degradation occurred through reduction and oxidation pathways via a direct Z-scheme mechanism. This work aims to describe the use of MOF-based materials as a visible-light-driven photocatalyst towards TC.

Development and fabrication of graphene oxide and reduced graphene oxide incorporated MnFe2O4@Bi2WO6 nanocomposite for efficient degradation of antibiotic drug as water contaminant under visible-light illumination

Tetracyclines are one category of extensively applied antibiotics. Meantime, owing to misapplication and inappropriate disposal, they are mostly discovered in wastewater, which causes a series of environmental contamination and stated a threat to a person's health and security. The present study investigates the photodegradation of tetracycline using MnFe2O4@Bi2WO6/graphene oxide, GO, and MnFe2O4@Bi2WO6/reduced graphene oxide, RGO, and MnFe2O4@Bi2WO6 nanocomposites as permanent photocatalyst with the aid of visible light. A facile microwave assisted combustion method was applied in solid state rapidly, conveniently to fabricate MnFe2O4@ Bi2WO6–GO and MnFe2O4@ Bi2WO6–rGO nanocomposites at low power 150 W and in time 10 min with very low amount of glycine (as fuel). Consequently, XRD, EDX Mapping, DRS, PL, TEM, FESEM, FTIR, VSM, BET and UV–Visible spectrophotometric analysis demonstrated characteristic of nanocomposites and specifications of existent photocatalyst. Magnetic investigations revealed that the MnFe2O4@ Bi2WO6-GO and MnFe2O4@ Bi2WO6–RGO nanocomposites can be easily separated from the solution by an external magnetic field. MnFe2O4@ Bi2WO6–GO nanocomposites were discovered with high specific surface area 73.83 m2/g than MnFe2O4@Bi2WO6–RGO nanocomposites with specific surface area 17.75 m2/g. Highest photocatalytic activity was determined for the MnFe2O4@ Bi2WO6–GO (catalyst-0.10 g/l, tetracycline antibiotic concentration 10 mg/l and at pH = 4) within 25 min of visible light irradiation without using any oxidizing agent. The investigation of kinetic study revealed that kinetic parameter specified to photodegradation and experimental outcomes follow first-order model. the superoxide, hydroxyl radicals, ℎ+ holes and light are the principal demonstrates of the reaction mechanism for the effective degradation of tetracycline drug. The evaluation of MnFe2O4@ Bi2WO6–GO and MnFe2O4@ Bi2WO6–RGO magnetic catalysts has proposed the encouraging and significant role of nanocomposites in perilous pharmaceuticals refinement from industrial wastewater and also, magnetically photocatalyst attributes can be used as a potent separable tool for eliminating water pollution problems in the various industry.