Degradation Rate Of Tetracycline Research Articles

Preparation of 2D/2D CoAl-LDH/BiO(OH)XI1−X Heterojunction Catalyst with Enhanced Visible–Light Photocatalytic Activity for Organic Pollutants Degradation in Water

Hydrotalcite/bismuth solid solution (2D/2D CoAl-LDH/BiO(OH)XI1−X) heterojunction photocatalysts were fabricated through a hydrothermal route. Because of their identical layered structure and interlayer hydroxides, CoAl-LDH(2D) and BiO(OH)XI1−X(2D) form a tightly bonded heterojunction, resulting in efficient light absorption, excitation, and carrier migration conversion. At the same time, the large specific surface area and abundant hydroxyl groups of the layered structure make the heterojunction catalyst exhibit excellent performance in the photocatalytic degradation of organic pollutants. Under visible light irradiation and in the presence of 1 g/L of the catalyst, 10 mg/L of methyl orange (MO) in water could be completely degraded within 20 min, and the degradation rate of tetracycline (TC) reached 99.23% within 5 min. CoAl-LDH/BiO(OH)XI1−X still maintained good photocatalytic degradation activity of tetracycline after five cycles, and the structure of the catalyst did not change. The reaction mechanism related to the degradation of TC by photocatalytic reactions was explored in detail, and the photoexcitation of the semiconductor heterojunction, as well as the subsequent free radical reaction process and the degradation pathway of TC were clarified. This work provides a promising strategy for the preparation of efficient photocatalytic materials and the development of water purification technology.

Enhanced Photocatalytic Degradation of Tetracycline by Magnetically Separable g-C3N4-Doped Magnetite@Titanium Dioxide Heterostructured Photocatalyst

Residual drug pollutants in water environments represent a severe risk to human health, so developing a cheap, environmentally friendly, and effective photocatalyst to deal with them has become a hot topic. Herein, a magnetically separable Fe3O4@TiO2/g-C3N4 photocatalyst with a special heterojunction structure was fabricated, and its photocatalytic performance was assessed by degrading tetracycline (TC). Compared to Fe3O4@TiO2, the synthesized Fe3O4@TiO2/g-C3N4 exhibited superior TC degradation performance, which was primarily ascribed to the heterojunction formed between TiO2 and g-C3N4 and its ability to enhance the visible light absorption capacity and reduce the photoinduced electron/hole recombination rate. Moreover, a free radical capture experiment further confirmed that·O2− and h+ are the predominant components in the TC degradation reaction. Under UV–Vis irradiation, the TC degradation rate escalated to as high as 98% within 120 min. Moreover, Fe3O4@TiO2/g-C3N4 was demonstrated to be easily recovered by magnetic separation without any notable loss even after five cycles, showing exceptional stability and reusability. These findings indicate that Fe3O4@TiO2/g-C3N4 is a promising photocatalyst for environmental remediation that may provide a sustainable approach to degrading antibiotic pollutants in wastewater.

Synthesis of near-infrared-activated YF3:Yb3+, Tm3+/Bi2MoO6 upconversion photocatalytic materials for the photocatalytic degradation of antibiotics based on fluorescence resonance energy transfer

Photocatalytic degradation of pollutants, an ecofriendly technology, is widely used for environmental remediation. However, the design and synthesis of photocatalytic materials for near-infrared light photocatalysis are challenging. In this study, an upconversion photocatalyst with fluorescence resonance energy transfer (FRET), YF3:Yb3+, Tm3+/Bi2MoO6 (YFYT/BMO), was developed and synthesised based on rare-earth upconversion luminescence. YFYT converted near-infrared (NIR) light into blue–violet light via upconversion. The rapid decay of the fluorescence lifetime of YFYT/BMO at 478 nm (Tm3+:1G4-3H6) verified that FRET efficiently occurred between YFYT and BMO. The degradation rate of tetracycline by YFYT/BMO was 2.6 times higher than that by BMO under NIR light. A great enhancement of 42.1 % on the tetracycline degradation efficiency was achieved in YFYT/BMO compared with pure BMO within 90 min of visible-NIR irradiation. This study provides a basis for developing and designing rare-earth upconversion photocatalytic materials that can achieve excellent photocatalytic degradation of antibiotics using NIR light for environmental remediation.

Synthesis of Ag2CO3/TiO2/SiC with pH stability and chloride ion boosted for efficient photodegrading tetracycline under visible light

The increasing issue of antibiotic contamination in water has sparked significant interest in seeking effective solutions. In this research, a dual Z-scheme ternary photocatalyst Ag2CO3/TiO2/SiC (ATS) was synthesized by a mechanochemical-coprecipitation method. The experimental results demonstrated that the 15 %Ag2CO3/TiO2/SiC (ATS-15) reached a remarkable tetracycline (TC) degradation efficiency of 95.87 % (k = 0.1063 min−1) after a 30 min exposure to visible light, which was 46.22 and 13.63 times more effective than SiC (k = 0.0023 min−1) and TiO2/SiC (k = 0.0078 min−1), respectively. The synergistic effect of ATS ternary structure to promote Si electron transfer and SiC surface oxidation. The photocatalytic performance of ATS-15 was greatly enhanced due to the synergistic effect of Cl− and CO3•−, achieving 95 % of TC degradation within 5 min. In the ATS-15 system, Cl− converts a portion of Ag2CO3 into AgCl and establishes a quaternary electron transfer scheme with ATS-15, thereby enhancing the performance of the photocatalyst. ATS-15 photocatalyst can maintain TC degradation rate above 90 % among pH 3 to 9. The ATS-15 system also exhibits excellent adaptability to various water environment, achieving 94.01 % TC degradation rate in natural river water, with only a 1 % reduction. A novel treatment scheme for antibiotic pollution in a complex water environment was proposed by ATS-15 photocatalyst with high pH stability and water applicability.

Ag-TiO2 Photovoltaic Synergistic Field-catalyzed Degradation Performance of Tetracycline

Background: Tetracycline (TC), a commonly used antibiotic, is extensively utilized in the medical sector, leading to a significant annual discharge of tetracycline effluent into the water system, which harms both human health and the environment. background: Tetracycline (TC), a commonly used antibiotic, is extensively utilized in the medical sector, leading to a significant annual discharge of tetracycline effluent into the water system. This harms both human health and the environment. Objective: A novel technique was developed to address the issues of photogenerated carrier complexation and photocatalyst immobilization. Compared to traditional photocatalytic photoelectrodes, the suspended catalyst used in the photovoltaic synergy field is more stable and increases the solidliquid contact area between the catalyst and the pollutant. objective: This paper uses sol-gel-prepared Ag-doped-TiO2 materials for the photoelectrocatalytic degradation of TC. Methods: This paper uses sol-gel-prepared Ag-doped-TiO2 materials for the photoelectric synergistic field-catalyzed degradation of TC. The study examined how the Ag doping ratio, calcination conditions, catalyst injection, pH, electrolytes, and electrolyte injection affected photoelectric synergistic field-catalyzed degradation. The experiments were performed in a photocomposite field with a constant 50 mA current and a 357 nm UV lamp for 60 minutes. The composites underwent characterization using XRD, TEM, and XPS techniques. method: The study examined how the Ag doping ratio, calcination conditions, catalyst injection, pH, electrolytes, and electrolyte injection affected photoelectrocatalytic activity. The experiments were done in a photocomposite field with a constant 50 mA current and a 357 nm UV lamp for 60 minutes. The composites underwent characterization using XRD, TEM, and XPS techniques. Results: Ag-TiO2 photoelectric synergistic field-catalyzed reaction with 357 nm ultraviolet lamp irradiation for 60 min and a constant current of 50 mA degraded 5 mg/LTC under preparation conditions of molar doping ratio of Ti: Ag=100:0.5, roasting temperature of 500 °C, and roasting time of 2 h. The photoelectric synergistic field-catalyzed degradation process achieved a degradation rate of 90.49% for 5 mg/L TC, surpassing the combined degradation rates of electrocatalysis and photocatalysis. The quenching experiments demonstrated that the degradation rate of TC decreased from 90.49% in the absence of a quencher to 53.23%, 42.58%, and 74.52%. The presence of •OH had a more significant impact than h+ and •O2-. Conclusion: The findings suggest that Ag-TiO2 significantly enhanced the efficacy of photoelectric synergistic field-catalyzed degradation and can be employed to treat high-saline and lowconcentration TC. This establishes a benchmark for using photoelectrocatalytic materials based on titanium in treating organic wastewater. result: Ag-TiO2 photoelectrocatalytic reaction with 357 nm ultraviolet lamp irradiation for 60 min and constant current (50 mA) degraded 5 mg/LTC under preparation conditions of molar doping ratio of Ti: Ag=100:0.5, roasting temperature of 500 °C, and roasting time of 2 h. The photoelectrocatalytic process achieved a degradation rate of 90.49 % for 5 mg/L TC, surpassing the combined degradation rates of electrocatalysis and photocatalysis. The quenching experiments demonstrated that the degradation rate of TC decreased from 90.49 % in the absence of a quencher to 53.23 %, 42.58 %, and 74.52 %. The presence of •OH had a more significant impact than h+ and •O2-.

Acidification of La doped C3N4 for photocatalytic degradation of tetracycline

In this study, the photocatalytic performance of g-C3N4 is improved by doping lanthanum and hydrochloric acid acidification. The prepared samples were characterized by XRD, XPS, ICP, SEM, BET and UV vis DRS. From the SEM and BET results, it can be seen that both doping lanthanum and hydrochloric acid acidification can affect the microstructure of the sample to a certain extent, resulting in a larger specific surface area of the sample. According to UV–vis DRS, it can be determined that the doping of lanthanum and hydrochloric acid acidification have to some extent reduces the band gap of the sample, reduces the recombination rate of electron-hole pair in the sample, makes the photocatalytic process more likely to occur, and improves the photocatalytic performance. Compared with g-C3N4, g-C3N4/La samples have stronger photocatalytic performance, with a 2-hour photocatalytic degradation rate of 95.54 % for tetracycline in g-C3N4/La-400. Based on this, acidification of the sample can further improve its performance, and the 2-hour photocatalytic degradation rate of tetracycline in g-C3N4/La-HCl4 can reach 99.40 %. This study indicates that the doping of lanthanum and hydrochloric acid acidification treatment can improve the photocatalytic performance of g-C3N4. g-C3N4/La-HCl4 has certain application prospects in the degradation of tetracycline and other macromolecular organic compounds.

Homogenization spin coating strategy for synthesizing IM-BTO photocatalytic membrane aims to tetracycline selectively degradation

Photocatalytic membrane technology is a promising technology for advanced water treatment. However, as a simple, fast, and stable spin coating method for photocatalytic membrane preparation, the spin coating solution often used in spin coating can cause the pore plugging on the membrane surface and encapsulates photocatalysts, which seriously affects the flux of the membrane and the exposure of the photocatalytic active site. Here, this work adopted a homogenization spin coating strategy, using polyvinylidene difluoride (PVDF) solution as the spin coating solution to prepare the highly exposed imprinted bismuth titanate porous photocatalytic membrane (IM-BTOM). Due to the same composition of PVDF solution as the PVDF substrate membrane, IM-BTOM basically retained the good porous structure of the membrane. The homogenization spin coating strategy not only endowed IM-BTOM with high flux (4545.45 L m-2h−1 bar−1), but also prevented the encapsulation of IM-BTO powder materials, fully exposing the photocatalytic active sites, thereby obtaining better photocatalytic ability and selectivity. The degradation rate of tetracycline with IM-BTOM was nearly three times that with the conventional cellulose acetate spin coating membrane. Meanwhile, the existence of imprinting cavities also endowed IM-BTOM with high selectivity for the target pollutant, with a selectivity coefficient of up to 2.66. This work provides a new idea for preparing high-efficient photocatalytic membrane by spin coating.

Rational design of dual sites induced local electron rearrangement for enhanced photocatalytic oxygen activation

Efficiently activated molecular oxygen (O2) is considered a promising technique for the removal of antibiotics. However, how to effectively regulate electrons distribution to promote O2 activation remains a challenge at present. In this study, phosphorus and sodium co-doped carbon nitride (PNaCN) were designed to rearrange the electrons distribution to activate O2 for the degradation of tetracycline. The generation of •O2− was innovatively observed via in-situ O2 fitting Fourier transform infrared (FTIR) spectroscopy, demonstrating the outstanding O2 activation ability of PNa5. Density functional theory (DFT) further confirmed that the rational co-doping led to the rearrangement of local electrons, resulting in electron-rich Na sites and electron-deficient P sites. These sites exhibited greater susceptibility to O2 adsorption and charge transfer. Besides, the degradation rate of tetracycline was increased by 2.44 times using co-doped CN. This study provides a new inspiration for enhancing O2 activation by inducing electrons rearrangement.

Utilizing Self‐Floating Cu3BiS3 Polydopamine Polyurethane Sponges for Enhanced Water Purification: Harnessing the free radical and non‐radical in persulfate system

AbstractThe advanced oxidation process based on persulfate group is a promising technology for water purification. However, the synergistic effect of free radical and non‐free radical degradation is still not feasible in the persulfate activation process, which consumes a large amount of external energy. The self‐floating Cu3BiS3/polydopamine/polyurethane sponge was prepared using a simple method, resulting in high catalytic performance when activated by peroxydisulfate (PDS). The experiments conducted to identify free radicals showed that the degradation process of tetracycline (TC) involved the synergistic action of non‐radical 1O2 and free radicals (SO4⋅− and • OH) and the conversion of Cu+/Cu2+. The addition of Cl−, HCO3−, PO43−, and SO42− to the solution did not significantly affect the high degradation rate of TC. Furthermore, the interfacial evaporation process achieved a remarkable evaporation rate of 1.53 kg m−2 h−1 and produced reclaimed water without any detectable TC contaminants. The sponge also exhibited excellent salt resistance and chemical stability. This study provides valuable insights into the degradation of antibiotics and the desalination of seawater.

Fabrication of a Z-scheme Bi2MoO6/NiFe layered double hydroxide heterojunction for the visible light-driven degradation of tetracycline antibiotics

Heterojunction catalysts offer promising potential for efficient and sustainable remediation of polluted environments. In this study, Z-scheme Bi2MoO6/NiFe layered double hydroxide (BMO/NiFe) heterojunction catalysts were synthesized using solvothermal process. The surface morphology, crystalline structure, and photochemical characteristics of the synthesized photocatalyst were analyzed by several spectroscopic and electron microscopy methods. BMO, NiFe and BMO/NiFe were efficiently utilized for tetracycline (TC) antibiotics degradation under visible light irradiation. The experimental findings suggest that the BMO/NiFe15 heterojunction catalyst greatly enhances the TC degradation rate to 95 % under 300 W visible light irradiation for 120 min. The rate constant of 0.0219 min−1 indicates a rapid degradation process following pseudo first-order kinetics. Furthermore, the effect of active free radicals, the recyclability of the catalyst and the photocatalytic degradation mechanism of TC were proposed. This novel method opens up possibilities for creating advanced photocatalysts, which can effectively degrade TC in water bodies, addressing the urgent need for its removal from aquatic environments. The present work serves as a primary pathway to design and develop efficient Bi2MoO6-based direct Z-scheme photocatalysts with promising applications in simultaneous wastewater degradation with hydrogen evolution.

Construction of MoS42− intercalated NiAl-layered double hydroxide by solvent-free method for promoting photocatalytic degradation of antibiotics: Synergistic effect of oxygen vacancies and electron-rich groups

MoS42− intercalated NiAl-layered double hydroxides (LDH) were prepared by solvent-free techniques, which possessed oxygen vacancies and efficient electron transfer channels. Oxygen vacancies were increased with increasing of the MoS42− intercalation amount. Through X-ray Photoelectron Spectroscopy (XPS), Electron Paramagnetic Resonance (EPR), Kelvin Probe Force Microscopy (KPFM), and Density Functional Theory (DFT), the presence of oxygen vacancies and electron transfer channels were confirmed. In the meantime, the formation mechanisms of electron transfer channels and the synergistic mechanisms involving oxygen vacancies and electron transfer channels were illustrated. Electrochemical characterization revealed that compared with LDH, the electron lifetime of LDH-WM-0.5 increased from 1.70 ns to 2.88 ns, and the recombination efficiency of electron holes was reduced by about 6 times. Degradation experiments demonstrated that the degradation rate of tetracycline by LDH-WM-0.5 increased from 19.0 % to 90.0 % in 3 h, representing a 4.5-fold improvement compared to LDH photocatalysts. This study contributed novel insights into developing advanced photocatalysts by strategically manipulating the presence of oxygen vacancies and constructing the electron transfer channels.

Tunable schiff-based networks with different bonding sites for enhanced photocatalytic activity under visible-light irradiation: The effects of steric hindrance

Organic polymers hold great potential in photocatalysis considering their low cost, structural tailorability, and well-controlled degree of conjugation for efficient electron transfer. Among the polymers, Schiff base networks (SNWs) with high nitrogen content have been noticed. Herein, a series of SNWs is synthesized based on the melamine units and dialdehydes with different bonding sites. The chemical and structural variation caused by steric hindrance as well as the related photoelectric properties of the SNW samples are investigated, along with the application exploration on photocatalytic degradation and energy production. The results demonstrate that only SNW-o based on o-phthalaldehyde responds to visible light, which extends to over 550 nm. SNW-o shows the highest tetracycline degradation rate of 0.02516 min−1, under 60-min visible light irradiation. Moreover, the H2O2 production of SNW-o is 2.14 times higher than that of g-C3N4. The enhanced photocatalytic activity could be ascribed to the enlarged visible light adsorption and intramolecular electron transfer. This study indicates the possibility to regulate the optical and electrical properties of organic photocatalysts on a molecular level, providing an effective strategy for rational supramolecular engineering to the applications of organic materials in photocatalysis.

Critical role of hydrogen bonding between microcrystalline cellulose and g-C3N4 enables highly efficient photocatalysis.

Developing a highly efficient photocatalyst for energy and environmental applications is urgently required. Herein, graphitic carbon nitride (CN) coupled with microcrystalline cellulose (MCC) (denoted as MCC-X/CN) shows excellent photocatalytic performance for tetracycline (TC) degradation and H2 evolution. And the optimized MCC-0.05/CN shows an improved TC degradation rate (Kapp = 0.019 min-1) and H2 evolution rate (642.71 μmol g-1 h-1), which are 1.9 and 22 times higher than those of pure CN, respectively. This improvement primarily results from hydrogen bonding (H-bonding) between CN and MCC, which enables excellent charge separation and migration, leading to the outstanding photoelectrochemical properties of MCC-0.05/CN.

Influencing mechanisms of tartaric acid on adsorption and degradation of tetracycline on goethite: insight from solid and liquid aspects.

The interactions between organic pollutants and iron minerals play an important role in their environmental fate. In this study, the effects of low-molecular-weight organic acids (LMWOAs) on the adsorption and degradation of tetracycline (TC) on goethite were investigated. Tartaric acid (TA) was taken as the representative of LMWOAs to study the influencing mechanism through batch experiments and microscale characterization. In addition, the properties of TC-TA clusters under different pHs were determined by density functional theory (DFT) calculations. The results showed that all five LMWOAs inhibited TC adsorption and degradation. The preferential adsorption of TA on goethite changed TC adsorption from inner spherical to outer spherical complexation and mainly inhibited TC adsorption and degradation of the singly coordinated hydroxyl group. TC degradation rate decreased from 0.0287 to 0h-1 in the first stage. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results showed that TA could influence the interactions of amide groups, C = O on the A-ring, and dimethylamino group of TC with goethite, and the formation of ≡Fe(II) was inhibited. In addition to competing for the effective sites, the effects of complexation between TA and TC in solution should be considered. According to DFT calculations, hydrogen bonds could be formed between the carboxyl group of TA and the H atom of TC at different pH. These findings can provide evidence for estimating the contribution of adsorption and degradation to TC removal by iron oxides with the coexistence of LMWOAs in a soil-water environment.

The structure-dependent performance and peroxymonosulfate activation mechanism of vacancy-rich Co3S4 hollow nanocages for water purification

Heterogeneous peroxymonosulfate (PMS)-based catalysts have been widely used for pollutant removal from wastewater. However, their limited electron transfer and reactive oxygen species (ROS) utilization efficiency hinder their overall effectiveness. Herein, the sulfurization technique was employed to precisely control the thickness of vacancy-rich Co3S4 hollow nanocages derived from zeolitic imidazolate frameworks (ZIFs). As expected, the optimized H-Co3S4-4.0 exhibited an exceptional degradation rate of tetracycline (0.284 min−1, TC) and a remarkably high PMS utilization efficiency (91.5 %). The experimental results indicated that the degradation of contaminants was primarily driven by the generation of singlet oxygen (1O2). Furthermore, the synergistic effects of reduced sulfur species and hollow structure not only accelerated the Co3+/Co2+ redox cycle but also facilitated the enrichment of reactants, thereby enhancing the long-term catalytic activity. Notably, the H-Co3S4-4.0-based flow-through unit exhibited no decline in the removal of TC during continuous operation for 12 h and significantly reduced its biological toxicity. Overall, the combination of nanoconfinement and hollow strategies will prove to be an effective method for fabricating practical catalysts for remediating water pollution.

Preparation and photocatalytic activity of CoFe2O4 nanoparticle modified rod-like Mn0.3Cd0.7S photocatalysts with S-scheme heterojunction

With the continuous progress of photocatalytic technology in environmental pollution control, the recovery of photocatalysts has gradually become a hot topic of concern. To solve this problem, a magnetically recoverable rod-shaped CoFe2O4/Mn0.3Cd0.7S with S-scheme heterojunction photocatalyst was successfully constructed. The phase composition, morphology, light absorption, and surface chemical environment of the samples were measured. The photocatalytic degradation rate of tetracycline by CoFe2O4/Mn0.3Cd0.7S is higher than that either of CoFe2O4 and Mn0.3Cd0.7S. The degradation efficiency of 1%CoFe2O4/Mn0.3Cd0.7S showed the best performance of 82.1% within 60 min. The rate constant for first-order kinetics of 1%CoFe2O4/Mn0.3Cd0.7S was about 1.72 times that of pure Mn0.3Cd0.7S. It was found that the enhanced photoactivity of the CoFe2O4/Mn0.3Cd0.7S heterojunction photocatalyst was due to the wider absorption range of visible light and the improved inhibition of electron and hole recombination. It is also found that the CoFe2O4/Mn0.3Cd0.7S heterojunction photocatalyst has excellent magnetic recovery ability under the external magnetic field. The photostability of as-prepared CoFe2O4/Mn0.3Cd0.7S heterojunction photocatalyst was studied, and a reasonable S-scheme electron-hole transfer mechanism was proposed according to the band structure. These advances provide a new way to improve the photoactivity of magnetic recyclable photocatalysts, and the synthetic magnetic recyclable rod CoFe2O4/Mn0.3Cd0.7S has a potential application prospect in the degradation of water pollutants.

Three-dimensional Electrocatalytic Degradation of Tetracycline by Nano-Feooh

Nano-FeOOH catalysts were prepared by a co-precipitation method and characterized by XRD, SEM, XPS and BET to analyze the phase composition, surface morphology, elemental composition and specific surface area of FeOOH. Results showed that the FeOOH catalyst had large pore volume and surface area, providing more active sites for catalytic reactions. A 3D electrocatalytic system EC/PS/FeOOH was established to degrade tetracycline (TC), and the contributions of FeOOH adsorption, PS activation and electrocatalysis were investigated. It was found that the adsorption rate of TC on sole FeOOH was 42%, the degradation rate of TC in the PS/FeOOH system was 63.80%, and the degradation rate of TC in the 3D EC/PS/FeOOH system reached 72.97%, indicating the high electrocatalytic activity of FeOOH. Surface catalysis mechanism studies showed that the high catalytic activity of FeOOH could be attributed to electron transfer between Fe(II) and Fe(III) and adsorbed oxygen on its surface.

Synthesis of Pd-modified Fe3O4 loaded on montmorillonite catalyst for photocatalytic degradation of tetracycline

In this study, a straightforward and effective strategy is presented for the synthesis of Pd-modified Fe3O4 magnetic nanoparticles loaded on montmorillonite (Pd@Fe3O4/MMT). The synthesis process involved using montmorillonite as a template, and Pd@Fe3O4 nanoparticles were uniformly anchored on the surface of montmorillonite. Various characterization results proved the successfully preparation of Pd@Fe3O4/MMT, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), etc. The Pd@Fe3O4/MMT was found to possess photocatalytic activity on degradation of tetracycline (TC). Importantly, the introduce of MMT enhanced the catalytic activity due to the increased dispersion of nanoparticles The most favorable conditions were found to be pH 6, a catalyst concentration of 55 mg/L, H2O2 concentration of 0.19 g/mL, and an initial tetracycline concentration of 40 mg/L. Under these conditions, the degradation rate of tetracycline in the aqueous solution exceeded 84 %, indicating the high catalytic efficiency of the Pd@Fe3O4/MMT. The results of the free radical capture experiment and electron spin resonance (ESR) demonstrated that •OH radicals were responsible for the tetracycline degradation process. In conclusion, this study offers a simple and effective method for the preparation of Pd@Fe3O4/MMT nanocomposites with excellent catalytic activity for tetracycline degradation in aqueous solutions.

Trinity strategy prepared high-performance biochar for peroxydisulfate activation to degrade tetracycline

In this study, a novel high-performance biochar (BNC) was prepared using a trinity strategy of liquid templates, B/N co-doping, and one-step pyrolysis for activating peroxydisulfate (PDS) to degrade tetracycline (TC). The catalytic activity of BNC can be tuned by varying the boron doping ratio and pyrolysis temperature. Of these, the optimized product, BNC-2–900, degraded 80 % of TC (50 mg/L) in 30 min. The high degradation efficiency was attributed to the accelerated electron transfer originated by graphite N, CO, and B-N-C functional groups of BNC, in which the non-radical pathways containing electronic transfer and 1O2-mediated oxidation were indicated as the primary pathways for TC degradation. Furthermore, Box-Behnken design (BBD) was employed to optimize various operating parameters in the BNC/PDS system whereby optimal degradation conditions were determined: Initial TC concentration was 20 mg/L; PDS dosage was 64.57 mg; BNC dosage was 70.91 mg; Temperature was 50 °C; Initial pH was 8.3, where the TC degradation rate reached 100 %. This study provides a novel trinity strategy that combines stability, environmental friendliness, and facility for developing heteroatom-doped carbonaceous catalysts.

Interfacial bonded K-doped-C3N4@Bi2WO6 heterostructure for efficient photocatalytic degradation of tetracycline

Close interface contact and rapid electron directional transfer of heterojunction are key factors to promote the reaction activity and stability of photocatalyst, which play a critical role in the degradation of organic pollutants. Hence, a K-doped-C3N4@Bi2WO6 quantum dots heterostructure was successfully fabricated by an in-situ self-assembly strategy for photocatalytic degradation of tetracycline. The K-doped-C3N4 appears abundant N-defects and unsaturated coordination environment of carbon atoms around N defects. The C atoms around N defects bond with surface O atoms of Bi2WO6 quantum dots to form C-O bonds, which serve as a rapid migration pathway for photoexcited electrons and reduce the recombination of carriers, further promoting the photocatalyst stability. Moreover, Bi2WO6 quantum dots anchored on K-doped-C3N4 result in a Z-scheme heterojunction and realizes directional separation of electrons. The photoexcited holes in Bi2WO6 with high oxidation ability and photoexcited electrons in K-doped-C3N4 with high reduction ability are preserved for efficient tetracycline degradation. The optimized K-doped-C3N4@Bi2WO6 possesses a superior photocatalytic tetracycline degradation rate of 93 %, which is higher than pure C3N4 (40 %) and Bi2WO6 (48 %), respectively.