Tc Removal Research Articles

Synergistic activation of peroxymonosulfate for tetracycline hydrochloride degradation with SrTiO3/Ti3C2Tx photocatalyst

Peroxymonosulfate (PMS) is a promising technology for increasing the oxidation capacity and promoting the production of active species in the photocatalytic system. SrTiO3, a material with a perovskite crystal structure in a cubic form, can activate PMS on its surface and generate non-radical 1O2. Herein, SrTiO3/Ti3C2Tx (ST) composites were successfully synthesized using a hydrothermal method based on SrTiO3 materials. The photocatalytic activation of PMS resulted in the degradation of tetracycline hydrochloride (TC-HCl), with the ST-10 (10 wt% SrTiO3/Ti3C2Tx) composite showing the highest efficiency in TC removal and rapid degradation kinetics, achieving complete TC removal within 10 min. The synergistic interaction between the two components in ST-10 significantly enhanced the activation of peroxymonosulfate (PMS), leading to an increased production of free radicals. The larger specific surface area and presence of –OH groups in the composite material facilitated the adsorption and chemical bonding of PMS molecules, thereby improving their overall performance. Quench experiments and electron paramagnetic resonance analysis identified •SO4−, •OH, •O2– and 1O2 as the primary active species responsible for the degradation of TC. Additionally, the degradation pathway of TC was elucidated through mass spectrometry analysis. This study provides valuable insights for the development of effective photocatalysts as promising PMS catalysts in environmental applications.

Efficient degradation of tetracycline by cobalt ferrite modified alkaline solution nanofibrous Ti3C2Tx MXene activated peroxymonosulfate system: Mechanism analysis and pathway

Magnetic CoFe2O4 nanoparticles have received considerable attention as an activator for peroxymonosulfate (PMS) in the degradation of tetracycline. However, it is still challenging to construct CoFe2O4 composites with good dispersion and highly exposed reactive sites. Herein, the KOH fiber-functionalized MXene matrix decorated by cobalt ferrite nanoparticles (denoted as CoFe2O4@Alk-MXene) was developed by electrostatic self-assembly method. The layered fibrotic structure effectively disperses and fixes cobalt ferrite nanoparticles, increasing the exposure of reactive sites. The as-prepared CoFe2O4@Alk-MXene material exhibited rapid removal of 100% tetracycline hydrochloride (TC-HCl) within 10 minutes by activating PMS, leveraging the excellent conductivity of alkalized MXene and the efficient activation of transition metal atoms. The experimental and theoretical analysis revealed that the electron transfer process of Ti2+/Ti4+, Co2+/Co3+ and Fe3+/Fe2+, as well as the free radical and non-free radical attack behaviors produced by the adsorption of PMS by the composite, are the primary mechanisms for achieving rapid removal of pollutants. A comprehensive degradation mechanism and potential pathways were proposed based on these findings. Overall, CoFe2O4@Alk-MXene/PMS emerges as a promising catalytic system for TC removal.

Silk fibroin protein and graphene synergistically boosting the reactive oxygen species generation of PU/AgI photocatalytic membrane for tetracycline sustained removal

Solar-light driven organic pollutants degradation by the recyclable photocatalytic membrane materials emerges as a promising technology for sewage purification. However, low generation of reactive oxygen species severely constraints their photocatalytic activity. Herein, we introduce a novel hydrophilic PU/SF/GO/AgI composite photocatalytic membrane fabricated via adding silk fibroin (SF) and graphene oxide (GO) for TC removal. By visible light irradiation, the PU/SF/GO/AgI membrane with 66.7 wt% SF and 0.05 wt% GO degrades TC with 7-fold increase in comparison with the PU/AgI membrane. The enhance photocatalytic activity is primarily attributed to its efficient generation of reactive oxygen species facilitated by the improved hydrophilicity and boosted charge separation. FTIR and electrochemical results demonstrate that the SF and GO with rich surface oxygen-containing groups contribute to the formation of Ag-O bonds for accelerating charge migration and separation. Significantly, the improved hydrophilicity of PU/SF/GO membrane can not only provide rich binging sites for AgI loading, but also be benefitted to attract small molecules for facilitating to reactive oxygen species generation. As a result, •O2−, •OH and H2O2 concentrations produced in PU/SF/GO/AgI membrane system reaches up to 53.20 μmol g−1 h−1, 7.89 μmol g−1 h−1 and 16.52 μmol, respectively, 6.7, 15.4 and 5.1-times higher than PU/AgI membrane system. Meanwhile, under LED irradiation of 12 h, TC degradation efficiency by the dynamic membrane reactor equipped with PU/SF/GO/AgI can reach up to 53 % and achieve 41 % TOC removal, exceeding the pure PU/AgI and those of reported membrane materials. This work proves that tuning hydrophilicity and charge migration of PU membrane can enhance their photocatalytic activity and recyclability, which offers an effective strategy for constructing sustained solar-light driven photocatalytic membrane system.

Establishing photocatalysis-self-Fenton system over a S-scheme Fe/Fe2O3@CuBi2O4 for enhancing TC removal via in-situ generating H2O2 and Fe/Cu dual-metal electron cycle: Radical and non-radical pathways

A S-scheme Fe/Fe2O3@CBO photocatalyst was synthesized via a grinding calcination method, proficiently degrading tetracycline via radicals and non-radical. The reaction rate of Fe/Fe2O3@CBO-20 was recovered to 0.0255 min−1 that is 4.3 and 7.3 times as many as pristine Fe/Fe2O3 and CBO after introducing visible light at the degradation process. The characterization outcomes also bear out that the S-scheme heterojunction is formed by passivation layer Fe2O3 and CBO, which enhances the visible light responsiveness of catalyst and promotes the separation and transfer of photogenerated electrons to generate h+ and O2−. Meanwhile, the molecular oxygen is more easily activated to form H2O2 due to the strong reduction potential of the CB (−1.21 eV), further to facilitate the transformation of O2− to 1O2. And the carriers excited in CBO activate Cu+, forming a Cu/Fe dual-metal electron cycle. The generated Fe2+ reacts with H2O2 to establish photocatalysis-self-Fenton system to generate ·OH. Additionally, the high TC removal in simulated aquatic environment exhibit that the catalytic performance is slightly affected by practical wastewater and the cyclic experiment show the stability and practicality. In conclusion, innovatively employing Fe/Fe2O3 for pollutant degradation via photocatalytic technology, this research paves a promising and efficacious pathway for the application of Fe/Fe2O3.

Inducing three-phase interface to enhance hydroxyl radical production via green atomic H*-mediated electro-Fenton process for highly-efficient tetracycline degradation

Electro-Fenton system, a pivotal advanced oxidation process in wastewater treatment, inherently grapples with dual challenges of O2/solute transfer contradiction and Fe-dissolution deactivation. To surmount these obstacles, a sandwich Pd/C electrode (SE-Pd/C) featuring a three-phase interface (TPI) was fabricated by coating hydrophilic Pd/C catalyst layers onto hydrophobic graphite felt substrate for enhanced hydroxyl radical production through a green H*-mediated Fenton process. SE-Pd/C demonstrated superior performance with an 88.9% TC removal rate, outperforming hydrophilic (HIE, 68.4%) and hydrophobic (HOE, 47.9%) Pd/C electrodes. The underlying rationale for its high performance includes: (1) The TPI in SE-Pd/C optimized the concurrent mass transfer of O2 and TC, enabling an improved electrostatic TC adsorption capacity of 31.2% (versus 27.3% for HIE-Pd/C and 20.3% for HOE-Pd/C), alongside elevated H2O2 production reaching 8.6 g·L−1 (compared to 0.02 g·L−1 for HIE and 2.0 g·L−1 for HOE); (2) The hydrophilic catalyst layer ensured a rich availability of electrochemically active Pd-sites, facilitating H* generation and subsequent H2O2 activation to form •OH (13.4 × 10−12 M·S > 6.7 × 10−12 M·S of HOE > 4.3 × 10−12 M·S of HIE). As H* could be electro-generated from both H+ and H2O, the SE-Pd/C system manifested robust adaptability across a wide pH range of 3−11, consistently achieving ≥ 88.9% TC removal. Thus, this research pioneered the synergy of TPI with the H*-mediated Fenton process, outlining a potent strategy for bolstered treatment of antibiotic-laden wastewater.

Novel active chlorine based-mechanism for 1O2-dominated tetracycline hydrochloride electrocatalytic oxidation over N-doped MXene

Chloride ions (Cl−) as electrolyte contribute remarkably to electrocatalytic oxidation because of the by-production of active chlorine. Experiment and theoretical calculation were proposed to clarify the contribution of Cl− to TC degradation, the generation and contribution mechanism of active chlorine, and the mutual transformation of active species. DFT results showed the favorable adsorption and conversion of Cl− on Ti-N, Ti-O-N, and Ti-N-O sites of Ti3C2Tx@N-0.1, thereby facilitating the generation of active chlorine and improving the TC degradation. The limited effect of direct electrocatalytic degradation (leading to O2– and 1O2 accumulation) and active chlorine (e.g., HClO) oxidation was proved by quenching, EPR, and qualification test of active species. The secondary and dominant production of 1O2 from active chlorine conversion was greatly improved in Ti3C2Tx@N-0.1/electrocatalysis system and played a crucial role in TC removal. The mutual transformation of OH, O2–, and 1O2 from direct electrocatalysis and secondary active chlorine conversion also enriched the TC removal mechanism. This research provides novel insights into the influence of active chlorine on electrocatalytic oxidation and the underlying mechanism.

Synergetic effect of green synthesized NZVI@Chitin-modified ZSM-5 for efficient oxidative degradation of tetracycline

The aggregation and limited activity of nanoscale zero-valent iron (NZVI) in aqueous media hinder its practical application. In this study, a cost-effective, environmentally friendly, robust, and efficient synthesis method for NZVI-based composite was developed. NZVI@Chitin-modified ZSM-5 (NZVI@C-ZSM) composite was facilely and greenly synthesized by loading NZVI into alkali-modified ZSM-5 molecular sieves after modifying with chitin as a surfactant and binder. NZVI@C-ZSM exhibited remarkable efficacy in TC removal, achieving a removal efficiency of 97.72% within 60 min. Compared with pristine NZVI, NZVI@C-ZSM demonstrated twice the removal efficiency, indicating that NZVI@C-ZSM effectively improved the dispersion and stability of NZVI. This enhancement provided more reactive sites for generating reactive oxygen species (ROS), significantly boosting catalytic activity and durability while reducing the potential risk of secondary pollution. An improved two-parameter pseudo-first-order kinetic model was used to effectively characterize the reaction kinetics. The mechanism for TC removal primarily involved an adsorption process and chemical oxidation-reduction reactions induced by hydroxyl radicals (•OH) and superoxide radicals (•O2−). Three potential degradation pathways for TC were suggested. Furthermore, NZVI@C-ZSM exhibited good resistance to interference, suggesting its broad potential for practical applications in complex environmental conditions. This study offers a viable material and method for addressing the issue of antibiotic-contaminated water, with potential applications in water resource management.

Synergistic effect of N doping and oxygen vacancies over TiO2 nanosheets with enhanced photocatalytic removal of tetracycline

The increasing pollution from non-biodegradable antibiotics poses a significant threat to ecosystems and human health. TiO2 is widely acknowledged as the premier photocatalyst for removing antibiotics from wastewater. To address the limitations of TiO2 in wide forbidden band width and low efficiency separation/migration of carriers, N-doping and oxygen vacancies (OVs) are co-modified within TiO2 nanosheets through the one-step calcination of a mixture of H2TiO3 and urea. The results indicate that the co-modified sample (TiO2-U5) exhibited the highest TC removal efficiency of 90% after 60 minutes of reaction, with a kinetic constant 3.6 times higher than that of pristine TiO2. The effective mineralization of TC is confirmed by three-dimensional excitation-emission matrix fluorescence spectroscopy (3D EEMs). Systematic characterization of the photocatalyst structure and monitoring of intermediates/products reveal that the synergistic effect of N-doping and oxygen vacancies (OVs) enhances band alignment, light response, and carrier separation/migration, thus improving the photocatalytic degradation performance of TC. This study highlights the significant potential of adjusting charge transport and enriching active sites through the co-introduction of doping and surface defects on TiO2 for the photocatalytic degradation of antibiotics.

The simultaneous removal of technetium and iodine from Hanford tank waste

The simultaneous removal of radionuclides technetium-99 and iodine-129 from an actual decontaminated Hanford tank waste sample (a mixture of decontaminated waste from tanks 241-AP-105 and 241-AP-107) was demonstrated for the first time in this work. A series of commercially available ion exchange resins were evaluated in batch contact tests in the tank waste, and all showed removal of both Tc and I. The highest Tc removal from the tank waste was observed for Purolite A530e while the highest iodine removal was observed for ResinTech SIR-110-MP. Isotherm tests in simulated tank waste with these two resins showed that the SIR-110-HP-MP had consistently higher Kd for both pertechnetate and iodide; with much higher Kd than previous works on Tc removal from Hanford waste. As such, the SIR-110-MP was evaluated in a dual-column (lead/lag) test processing 5.2L of the tank waste mixture showing 50 % breakthrough of Tc on the lead column and no significant breakthrough on the lag after 641 bed volumes (BV, 6 mL size) while significant iodine breakthrough (>50 %) occurred after 28 BV. The limited iodine uptake was attributed to the column conditions generating mass transfer limitations. A fraction of the Tc and I was not captured by the resin (<10 %) in either the batch tests or column tests. The iodine fraction is not iodate and is likely organo-iodide. The fraction of the Tc was identified as a non-pertechnetate species which is the first time non-pertechnetate has been identified in AP-105 and AP-107 tanks. This non-pertechnetate fraction contained Tc(I) and for the first time a stable Tc(VI) species in Hanford waste was identified..

Mechanistic insight into efficient PPCPs removal on waste biological activated carbon for low-carbon emission reutilization

Over 3.9 × 107 t/a of biological activated carbon (BAC) waste was generated from Chinese drinking water treatment plants. Traditional disposal methods, such as thermal regeneration and incineration, contributed significantly to high energy consumption and CO2 emissions. To tackle this issue, a low-carbon-emitting reutilization approach was proposed to reutilize waste BAC used for eight years (BAC-8Y) to efficiently remove pharmaceuticals and personal care products (PPCPs) from wastewater. The long-term operation of a BAC-8Y column demonstrated excellent removal efficiencies of tetracycline hydrochloride (TC, >98%) and diclofenac sodium (DS, >90%) with the original concentrations of 2–5 mg/L in the artificially prepared wastewater. Even for the real sewage with the addition of 2 mg/L DS/TC, BAC-8Y could also achieve >99 % removal efficiency for both within 40 days. The results of the adsorption control test using thimerosal to inhibit microbial activity showed that adsorption contributed 94.94% of the TC removal by BAC-8Y, while the DS removal benefitted from the combined effect of adsorption (69.10%) and biodegradation (30.90%). Microbial analysis revealed that Acidobacteriota and Dadabacteria was the dominant phyla, while norank_f__Blastocatellaceae and norank_f__Oxalobacteraceae was the key genera. Moreover, compared to traditional methods, the carbon emission from reutilizing 1 t waste BAC in this study was negligible (4.18 kgCO2), which was mainly from transportation. This was also aligned with China's carbon peaking and carbon neutrality goals.

DFT Predirected Molecular Engineering Design of Donor-Acceptor Structured g-C3N4 for Efficient Photocatalytic Tetracycline Abatement.

The photocatalytic environmental decontamination ability of carbon nitride (g-C3N4, CN) typically suffers from their inherent structural defects, causing rapid recombination of photogenerated carriers. Conjugating CN with tailored donor-acceptor (D-A) units to counteract this problem through electronic restructuring becomes a feasible strategy, where confirmation by density functional theory (DFT) calculations becomes indispensable. Herein, DFT is employed to predirect the copolymerization modification of CN by benzene derivatives, screening benzaldehyde as the optimal electron-donating candidate for the construction of reoriented intramolecular charge transfer path. Experimental characterization and testing corroborate the formation of a narrowed bandgap as well as high photoinduced carrier separation. Consequently, the optimal BzCN-2 exhibited superior photocatalytic capacity in application for tetracycline hydrochloride degradation, with 3.73 times higher than that of CN. Besides, the BzCN-2-based photocatalytic system is determined to have a toxicity-mitigating effect on TC removal via T.E.S.T and prefers the removal of dissociable TC2- species under partial alkalinity. This work provides insight into DFT guidance for the design of D-A conjugated polymer and its application scenarios in photocatalytic decontamination.

Synthesis of S-scheme 0D/2D Co2ZrO5/g-C3N4 heterojunction photocatalyst with enhanced visible-light photocatalytic activity for tetracycline

The step-like scheme (S-scheme) heterojunction photocatalyst, which possess an improved electric field, intimate interfacial contact and reasonable energy band structure, is one of the most optimal ways to solve the wastewater problem caused by residual antibiotics. Herein, a new type of S-scheme 0D/2D Co2ZrO5/g-C3N4 (CZO/CN) heterojunction photocatalyst was prepared via an ultrasonic assisted hydrothermal method and used as photocatalyst to degrade tetracycline (TC, 20 mg/L, 100 mL). Compared to pure CN and CZO, the CZO/CN with the optimal design proportion (30CZO/CN) demonstrates the outstanding photocatalytic efficiency for TC degradation under visible-light irradiation, with the degradation rate being 94.8 % within 180 min at pH 5.0. Moreover, the 30CZO/CN exhibits superior stability, which still eliminated 90 % of TC after five times cycle runs. Furthermore, the S-scheme mechanism of photocatalytic TC removal by CZO/CN is proposed by XRD, FT-IR, XPS, UV–Vis DRS and PL analysis, which summarized that the enhanced photocatalytic activity of CZO/CN was mainly ascribed to its larger specific surface area, available light absorption region and appropriate bandgap width, dominated by the S-scheme pattern. This study presents a novel S-scheme g-C3N4-base heterojunction photocatalyst can effectively treat wastewater and provides design ideas for other heterojunctions.

V2O5·3H2O/N-doped graphite felt cathode efficiently produced H2O2 and ·OH in the electro-Fenton system for enhanced antibiotics degradation

Enhancing H2O2 production and promoting the conversion of H2O2 to ·OH are two major problems that needed to be solved in electro-Fenton process. Herein, the V2O5·3H2O/N-doped graphite felt (V2O5·3 H2O/N-GF) cathode was developed to construct electro-Fenton system for antibiotics degradation. Benefiting from that the N-GF which possessed a large number of 2e-ORR active sites for H2O2 production, and the V2O5·3H2O particles could efficiently activate H2O2 to produce ·OH, the V2O5·3 H2O/N1-GF cathode exhibited outstanding catalytic activity. Besides, the V2O5·3 H2O/N1-GF cathode exhibited only 30 mV overpotential difference between the optimal oxygen reduction potential (OP ORR) and the optimal vanadium reduction potential (OP VRR), thereby facilitating ·OH generation. The V2O5·3 H2O/N1-GF cathode displayed desired degradation performance in a wide pH range (2.1–7.2), with TC removal of 93.8% within 60 min at pH of 3.3, and total organic carbon (TOC) removal of 62.8%. DFT calculations revealed that V2O5·3H2O were more readily to adsorb H2O2 than V2O5, which was conducive to improving H2O2 utilization and conversion. Four possible degradation pathways for TC were proposed and toxicity analysis of the intermediates were determined. The V2O5·3H2O/N1-GF could also decompose various antibiotics effectively in the system, and it exhibited great stability. This work can provide reference for designing efficient V-based cathode for electro-Fenton system.

Manipulating spin-polarization of Co-doped ZnFe2O4 for photocatalytic TC degradation

The rapid recombination of photogenerated electrons and holes was an enormous hindrance constraining the photocatalytic efficiency of photocatalysis, which could be effectively solved by inducing electron spin-polarization. Herein, a series of gradient ZnFe2-x Co x O4 (ZFCO-x) magnetic compounds with spin-polarization properties were synthesized by doping Co cation into ZnFe2O4, as well as the diffraction of x-rays characterization confirmed the successful synthesis of the samples. In photodegradation experiments, ZFCO-0.8 manifested improved photocatalytic degradation efficiency in TC removal experiments with visible-light exposure and external magnetic field. Furthermore, the photodegradation experiments exhibited that the degradation efficiency of ZFCO-x could be raised through Co doping and the photocatalytic degradation efficiency was significantly improved under an external magnetic field. The sample exhibiting the most prominent enhancement was ZFCO-x with doping content of x = 0.8, which displayed 48% photocatalytic degradation performance enhancement with a magnetic field. Density functional theory was used to calculate the density of states (DOS) of materials. The calculated DOS indicated that ZFCO-0.8 exhibited the most intense spin-polarization consistent with the results of the experiment. This work is anticipated to deliver an operating method for manipulating spin-polarization in photocatalytic semiconductors to improve photocatalytic degradation efficiency.

Non-radical activation of peroxymonosulfate for degradation of antibiotics in saline environments by biochar flakes prepared with molten salt strategy

Due to the serious interference of inorganic salts, it is very important to develop a peroxymonosulfate (PMS) oxidation system that can operate normally and efficiently in saline environments. Herein, the Fe-N-doped biochar flakes (FSBC) derived from sesame powder were developed with the help of molten salt strategy for activating PMS to achieve efficient degradation of tetracycline in salt environment. The effect of calcination temperature on physical and chemical properties was studied to further optimize the performance of the catalyst. FSBC-800 showed the best activation performance for PMS, with a TC removal rate of ∼ 94 % within 10 min. Mechanism research shows that FSBC-800 activates PMS through singlet oxygen (1O2) and electron transfer, so the reaction system is extremely selective and can almost avoid interference from various inorganic ions. The FSBC-800/PMS system can operate efficiently in the coexistence of 8 common anions/cations (0–250 mM), and salinity of 0.1–5.0 wt% has almost no negative impact on the system. In addition, possible degradation pathways of tetracycline were proposed, and the toxicity of intermediate products during the degradation process was evaluated. This study provides a PMS oxidation system with strong selectivity that can cope with various complex saline environments.

One-step synthesis of iron and nitrogen co-doped porous biochar for efficient removal of tetracycline from water: Adsorption performance and fixed-bed column

Here, Fe/N co-doped porous biochars (FeNKBCs) were obtained by grinding corncob, CH3COOK, FeCl3·6H2O, and C3H6N6 via one-step synthesis and were applied to remove antibiotics from wastewater. Notably, CH3COOK had an excellent porous activation ability. The developed nanotubular structure of Fe1N2KBC had a high pore volume (Vtotal) (1.2131 cm3/g) and specific surface areas (SSA) (2083.54 m2/g), which showed outstanding sorption abilities for TC (764.35 mg/g), OTC (560.82 mg/g), SMX (291.45 mg/g), and SMT (354.65 mg/g). The adsorption process of TC was controlled by chemisorption. Moreover, Fe1N2KBC has an excellent dynamic adsorption performance (620.14 mg/g) in a fixed-bed column. The properties of SSA, Vtotal, and the content of graphite N and Fe–N were positively correlated with TC adsorption capacity. The high performance of TC removal was related to π-π stacking, pore-filling, hydrogen bond, and electrostatic interaction. Fe1N2KBC possessed stable sorption amounts in pH 2–12 and actual water, and well reuse performance. The results of this work present an effective preparation method of Fe/N porous biochar for TC-contaminated water remediation.

Ti3C2-assisted construction of Z-scheme MIL-88A(Fe)/Ti3C2/RF heterojunction: Multifunctional photocatalysis-in-situ-self-Fenton catalyst

The applicability of the conventional Fenton reaction is limited due to several factors, including the high cost and slow redox cycle of Fe3+/Fe2+, the requirement for harsh acidic conditions, and the insufficient presence of hydroxyl radicals for the ring-opening reaction. The combination of photocatalysis and Fenton technology to create a photocatalysis-in-situ-self-Fenton (PISF) system is a viable approach for addressing the inherent limitations of conventional Fenton reactions. Herein, a multifunctional PISF system, MIL-88A(Fe)/Ti3C2 MXene/resorcinol-formaldehyde (MIL-88A(Fe)/Ti3C2/RF, MTR) Z-scheme heterojunction, was designed and constructed for degradating organics and inactivating bacteria. With the assistance of Ti3C2, the degradation rate of TC by MTR catalyst was 4.8 times that of MIL-88A(Fe)/RF catalyst under visible light irradiation. Meanwhile, good degradation performance was maintained after 5 cycling tests. The remarkable TC removal efficiency (97.4 %) and durability were attributed to the synergistic effect of the photocatalytic reaction and Fenton reaction. The photoinduced holes (h+) assist hydroxyl radicals (•OH) generated by the Fenton reaction for deeply mineralizing TC. The degradation intermediates, potential degradation pathways, and intermediates toxicity were comprehensively investigated to gain a deeper understanding of the catalytic process. Moreover, under visible light irradiation, the MTR killed 97.8 % of E. coli and 94.9 % of S. aureus within 120 min, demonstrating good antibacterial activity. This work provides a novel strategy to design PISF catalysts for environmental remediation.

Anchoring defective metal-free catalysts on montmorillonite nanosheets for tetracycline removal: synergetic adsorption-catalysis and mechanism insights

The hydroxyl groups on the MMT surface induced the formation of (–CN and N defects) and N defects in the composite samples, which promoted the adsorption of TC, PMS, and O2 molecules, and the generation of reactive species, improving the TC removal efficiency.

Catalytic PMS oxidation universality of CuFe2O4/MnO2 heterojunctions at multiple application scenarios

The magnetic CuFe2O4/MnO2 heterojunctions were prepared by hydrothermal method, and the effect of different reaction temperature on the physicochemical properties and catalytic activity was investigated. The CuFe2O4/MnO2 heterojunctions prepared at 100 °C can effectively activate peroxymonosulfate (PMS) at multiple application scenarios for degradation and mineralization of tetracycline, o-nitrophenol and ceftriaxone sodium under indoor light, visible light and dark condition. Additionally, the CuFe2O4/MnO2-PMS system showed high catalytic activity and anti-interference ability for degradation of pharmaceutical pollutants in natural water bodies and industrial wastewater. The TC removal efficiency in Qianhu Lake water, Ganjiang River water and tap water was about 88%, 92% and 89%, respectively. The CuFe2O4/MnO2-PMS system is also effective for actual pharmaceutical wastewater treatment with 77.9% of COD removal efficiency. Interestingly, the reactive species of CuFe2O4/MnO2-PMS system under visible light are different from those in dark condition, and the different catalytic mechanisms at multiple application scenarios were proposed. This work provides new insights into mechanism exploration of heterojunction catalyst for PMS activation.

N-enriched covalent organic polymer derived nanoscale zero-valent iron for effective oxidative degradation of tetracycline

Considering the agglomeration and instability of nanoscale zero-valent iron (NZVI, Fe0), N-enriched covalent organic polymer derived zero-valent iron (NZVI@N-COP) composite with excellent activity, high stability and as well as effective antibiotic removal capacity was innovatively synthesized via solvent thermal and in-situ reduction growth methods. The dispersion of NZVI is distinctly improved by using N-enriched covalent organic polymer (N-COP) as both matrix and dispersant. NZVI@N-COP exhibits excellent electron transfer capability and high TC removal efficiency without additional oxidants. The removal efficiency of TC was increased by 42.4% compared with that of pristine NZVI. The promoted activity of NZVI@N-COP can be ascribed to the strong coordination of Fe with N atoms between NZVI and N-COP, which reduces oxidation and leakage of Fe, exposing more available reactive sites to produce reactive oxygen species. Additionally, Characterization results show that the reaction mechanism involves adsorption and chemical oxidation of O2•– without additional oxidants. Optimum operating conditions were determined to be NZVI@N-COP dosage 0.1 g·L−1, pH 6, and temperature 298 K. This research put forward a simple method for synthesis of highly effective N-COP derived NZVI and its application in the treatment of antibiotic pollutants.