Catalytic Degradation Performance Research Articles

Degradation performance and mechanism of VOCs in asphalt by alkali metal-doped La2Ce2O7-based fluorite through pyroelectric and photocatalytic synergy

Under high-temperature construction conditions, the use of asphalt can release a large amount of volatile organic compounds (VOCs), which has adverse effect on the environment and human health. Part of fluorite oxides show potential application in VOCs conversion due to their excellent photoresponse and chemical stability in addition to ferroelectricity, piezoelectricity and pyroelectricity properties. In this paper, La2Ce2O7-based fluorite was modified with alkali metal doping and its photo-thermal coupling catalytic effects on the degradation performance of VOCs in asphalt were investigated. The results show that the fluorite catalysts La1.85A0.15Ce2O7 (A=Li, Na, K, Rb, Cs) have efficient electron-hole pair separation ability. Among them, the Rb+ doped La2Ce2O7 sample not only has stronger pyroelectric effect due to increased lattice distortion and oxygen vacancies, but also has the best photogenerated charge transport property and more favorable valence band position for oxidation reaction. Under the photo-thermal synergistic effect, the catalytic degradation performance of VOCs in asphalt by Rb+ doped La2Ce2O7 catalyst can reach 82.61 % at 50 min. Additionally, dynamic shear rheological tests indicate that the addition of catalysts at this blending ratio can enhance the rutting resistance of the asphalt material. This study introduces an innovative approach to enhance the efficiency of multi-field coupled degradation processes of volatile organic compounds (VOCs) in asphalt.

N-doped lignin-based activated carbon aerogel derived from bamboo black pulp liquor for efficient removal of malachite green in wastewater.

In this study, a lignin-based aerogel (LA) was prepared through acid precipitation of BPBL, followed by sol-gel method and freeze-drying. Additionally, a one-step activation-carbonization method was used to acquire nitrogen-doped lignin-based activated carbon aerogel (NLACA). The adsorption and catalytic degradation performance for malachite green (MG) were examined. The specific surface area of NLACA after N-doping was 2644.5 m2/g. The adsorption capacity for MG was increased to 3433mg/g with the presence of nitrogenous functional groups on surface of NLACA compared without N-doping. Meanwhile, non-radical singlet oxygen is the primary active substance and degradation efficiency arrives at 91.8% after the catalytic degradation within 20min and it has good stability and reuse. Three possible degradation pathways during degradation were analyzed by LC-MS technique. The adsorption isotherm and kinetic data demonstrated conformity with both the Langmuir model and the pseudo-second-order kinetic model. The primary mechanisms of the adsorption for MG dyes on NLACA include hydrogen bonding, π-π interactions, attraction of electrostatic and pore filling. Hence, NLACA derived from BPBL acts as a cost-effective and high-performance adsorbent and catalyst for removal of MG in dye wastewater. This concept introduces an innovative approach of "treatment of waste with waste" for developing a low-consumption, high-efficiency dye wastewater treatment and provides significant reference to treatment dye wastewater.

Dual defense against membrane fouling for efficient and sustainable oil/water separation on a novel super-hydrophilic/underwater superoleophobic and catalytic nanofibrous membrane

Membrane separation technology is widely recognized as an efficient method for treating organically polluted wastewater in virtue of high performance and straightforward operation. However, the practical application of membranes is inevitably confronted with contamination issues, presenting a major challenge in terms of fouling resistance. To address this issue, a defensive-offensive dual-defense strategy based on wettability and catalytic ability control is proposed. With this concept, a novel nanofibrous membrane with a unique structure was successfully prepared through polyacrylonitrile (PAN) electrospinning, pre-oxidation, CoFe Prussian blue analogue (PBA) and polypyrrole (PPy) modification, and calcination processes. For the passive defense mode, the as-prepared membrane has shown good underwater-superoleophobicity for various types of oils, good separation capability for corresponding oil–water emulsions with retention ratios of above 99 % and fluxes ranging from 231.5 to 1524.2 L·m−2·h−1·bar−1, as well as organic solvent (dimethylformamide, DMF) resistance. For the offensive defense mode, this membrane exhibits well catalytic degradation performance for refractory pollutants with the assistance of peroxymonosulfate (PMS), which is due to the membrane being decorated with catalytic nanoparticles that contain abundant encapsulated ultra-small Fe doped Co3O4 (∼2.28 nm), and that is much smaller than the size of the pristine PBA (∼33.8 nm). Notably, the surfactants present in oil-in-water emulsions are found to be the main cause of membrane fouling, where the cationic surfactants exhibit the most significant fouling effect, while the introduction of photo-Fenton-like catalysis can endow the membrane with excellent antifouling performance and extended service life, and nearly a fully recover of emulsion separation performance was achieved. Overall, this work paves pathways to the design of advanced membranes for sustainable wastewater treatment.

Catalytic properties of Fe-based amorphous alloys based on LPBF

Laser Powder Bed Fusion (LPBF) additive manufacturing technology has the advantages of high forming accuracy and rapid cooling. It is expected to overcome the limitations of forming difficulties in amorphous alloys and provide a new opportunity for the production of amorphous alloy structural parts. In this paper, FeSiBCrC amorphous alloy powder was used to prepare Fe-based amorphous alloy samples by LPBF technology. In view of the excellent properties of Fe-based amorphous alloy, the catalytic degradation performance of Fe-based amorphous alloy samples prepared by LPBF was systematically investigated. The catalytic degradation performance of the Fe-based amorphous alloy was optimised by changing the reaction conditions. In the methyl orange (MO) dye degradation experiment, the degradation rate reached 90.99% within 10 min. Increasing the sample dosage and reaction temperature can improve the degradation efficiency, but excessive addition of H2O2, raising the pH and the initial dye concentration will reduce the degradation efficiency. In addition, in the cyclic catalytic experiment, it was found that it has self-renewing performance, and the degradation efficiency was still higher than 95% within 35 minutes after repeated degradation 12 times. Fe-based amorphous alloy catalysts prepared on the basis of LPBF have good catalytic activity and will provide economical and effective technical support for wastewater treatment.

Synthesis and Characterization of Titania-Coated Hollow Mesoporous Hydroxyapatite Composites for Photocatalytic Degradation of Methyl Red Dye in Water

Hollow mesoporous hydroxyapatite (HM-HAP) composites coated with titania are prepared to increase the stability and catalytic performance of titania for azo dyes present in the wastewater system. In this work, HM-HAP particles were first synthesized by a hydrothermal method utilizing the CaCO3 core as a template and then coated with titania to form TiO2/HM-HAP composites. Utilizing SEM, XRD, XPS, BET, FTIR, EDS, UV–vis DRS spectroscopy, and point of zero charge (PZC) analysis, the coating morphological and physicochemical parameters of the produced samples were analyzed. The photocatalytic efficiency of the synthesized coated composites was assessed by the degradation of methyl red (MR) dye in water. The results indicated that TiO2/HM-HAP particles could efficiently photodegrade MR dye in water under UV irradiation. The 20% TiO2/HM-HAP coating exhibited high catalytic performance, and the degradation process was followed by the pseudo-first-order (PFO) kinetic model with a rate constant of 0.033. The effect of pH on the degradation process was also evaluated, and the maximum degradation was observed at pH 6. The analysis of degraded MR dye products was investigated using LC-MS and FTIR analysis. Finally, a good support material, HM-HAP for TiO2 coatings, which provides a large number of active adsorption sites and has catalytic degradation performance for MR dye, was revealed.

Construction of a Wood Nanofiber-Bismuth Halide Photocatalyst and Catalytic Degradation Performance of Tetracycline from Aqueous Solutions.

Nanostructured bismuth oxide bromide (BiOBr) has attracted considerable attention as a visible light catalyst. However, its photocatalytic degradation efficiency is limited by its low specific surface area. In this study, a solvothermal approach was employed to synthesize BiOBr, which was subsequently loaded onto cellulose nanofibers (CNFs) to obtain a bismuth halide composite catalyst. The performance of this catalyst in the removal of refractory organic pollutants such as tetracycline (TC) from solutions under visible light excitation was examined. Our results indicate that BiOBr/CNF effectively removes TC from the solution under light conditions. At a catalyst dosage of 100 mg/L, the removal efficiency for TC (with an initial concentration of 100 mg/L) was 94.2%. This study elucidates the relationship between the microstructure of BiOBr/CNF composite catalysts and their improved photocatalytic activity, offering a new method for effectively removing pollutants from water.

Cobalt germanium hydroxides with asymmetric electron distribution and surface hydroxyl groups for superb catalytic degradation performances

Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) are attractive approaches for solving the global problem of water pollution, due to the generation of highly-active reactive oxygen species (ROS). Therefore, highly-efficient PMS activation is crucial for promoting the catalytic degradation of environmental pollutants. Here, bimetallic CoGeO2(OH)2 nanosheets with abundant surface hydroxyl groups (CGH) were synthesized via a simple hydrothermal route for PMS activation and degradation of various organic contaminants for the first time. The abundant surface hydroxyl groups (≡Co–OH/≡Ge–OH) could promptly initiate PMS to generate highly-active radicals: singlet oxygen (1O2), sulfate radicals (SO4·−) and hydroxyl radicals (HO•), while the asymmetric electron distribution among Co–O–Ge bonds derived from the higher electronegativity of Ge than Co further enhances the quick electron transfer to promote the redox cycle of Co2+/Co3+ and Ge2+/Ge4+, thereby achieving an outstanding catalytic capability. The optimal catalyst exhibits nearly 100 % catalytic degradation performance of dyes (Methylene blue, Rhodamine B, Methyl orange, Orange II, Methyl green) and antibiotics (Norfloxacin, Bisphenol A, Tetracycline) over a wide pH range of 3–11 and under different coexisting anion conditions (Cl−, HCO3–, NO3–, HA), suggesting the excellent adaptability for practical usage. This study could potentially lead to novel perspectives on the remediation of water areas such as groundwater and deep-water areas.

Ti-doped synergistic hollow thin-walled Bi2O3 nano-microspheres for efficient tetracycline hydrochloride photodegradation

Bismuth oxide (Bi2O3) has been extensively investigated in the fields of environmental photocatalysis, owing to its exceptional charge transport performance and remarkable resistance to photocorrosion. However, the limited absorption spectrum of light and rapid recombination of photogenerated charge results in a low quantum efficiency. Herein, an efficient photocatalytic system for tetracycline hydrochloride (TCH) photodegradation based on titanium (Ti)-doped hollow, thin-walled Bi2O3 with nano-microspheres is fabricated via a facile self-assembly strategy. It is shown that doping Ti in Bi2O3 can generate oxygen vacancies, in addition, the addition of Ti in the solvothermal process inhibits the conversion of Bi3+ to bismuth at high temperature, making the content of each component in the heterostructure controllable. The hybrid catalyst exhibits superior performance in visible-light-driven photocatalytic degradation of TCH (about 95.1 % degradation efficiency after 120 min) and excellent stability (up to 4 cycles) under visible light irradiation. The optimized catalyst exhibits excellent performance in visible light catalytic degradation, owing to the synergistic effect of high specific surface area, Bi plasma resonance effect and charge mobility. Moreover, the photocatalytic mechanism of Ti-Bi2O3 have been deeply analyzed through experimental investigation and DFT theoretical calculations. The findings contribute to the synthesis of efficient visible-light-driven Bi-based photocatalysts and to the understanding of photocatalytic degradation reactions.

Pd octahedra nanocubes mediated photo-fenton catalytic performance for sustainable degradation of methylene blue

This research utilized a typical solvothermal approach, by employing Na2PdCl4 as the synthetic precursor, L-ascorbic acid (AA) as the reductant agent, and polyvinylpyrrolidone (PVP) as the practical surfactant, palladium (Pd) octahedra was finally effectively synthesized by the hydrothermal and solvothermal methods. Subsequently, characterizations of Pd octahedra were conducted by using TEM, XPS, XRD, and other analytical methods. Whereafter, Pd octahedra displayed a consistent shape and size, featuring a distinctive tip-shaped structure, which conferred upon them outstanding optical absorption properties within the near-infrared (NIR) region. Consequently, under NIR laser exposure, Pd octahedra could elevate local reaction temperature via in-situ photothermal conversion, thereby stimulating the formation of active sites of Fenton catalysts. The Photo-Fenton catalytic activity of Pd octahedra was investigated by using methylene blue (MB) as a model pollutant. The degradation efficiency of MB reached 94.8 % within 35 min under 808 nm laser irradiation, and the removal rate of MB by Pd octahedra could still reach more than 90 % after five cycles of use. All the results manifest that Pd octahedra exhibit excellent purification performance for MB dyestuff wastewater.

Mussel‐inspired self‐assembly of silver nanoclusters into multifunctional silver aerogels for enhanced catalytic and bactericidal applications

AbstractSilver nanoclusters (AgNCs) have shown broad application prospects in catalysis, sensing, and biological fields. However, the limited stability of AgNCs has become the main challenge restricting their practical application in complex environments. Herein, a mussel‐inspired, dopamine‐assisted self‐assembly approach is reported to fabricate 3D AgNC aerogels (PDA/AgNCs), which possess significantly enhanced structural stability and synergistic functional properties. The prepared AgNC aerogels display a hierarchical network structure with an ultrafine ligament size of 10.3 ± 1.2 nm and a high specific surface area of 50.7 m2 g−1. The gelation mechanism is elucidated by in‐depth characterization and time‐lapse monitoring of the gelation process vis spectroscopic and microscopic approaches. Owing to the distinct features of aerogels and the synergistic effect of AgNCs and PDA, the fabricated aerogels can not only efficiently decolorize dyes with a faster kinetic than individual AgNCs, but also exhibit remarkable broad‐spectrum antimicrobial activity. Consequently, a conceptual water‐treatment device is established by depositing PDA/AgNC aerogels on the cotton substrate, which shows good performance in both catalytic dye degradation and bacterial killing in the flowing system. This mussel‐inspired self‐assembly strategy has great potential in developing robust AgNC‐based functional materials, which also provides a new guideline for designing sophisticated materials with integrated functions and synergistic properties.

Synthesis of Fe-Loaded Biochar Obtained from Rape Straw for Enhanced Degradation of Emerging Contaminant Antibiotic Metronidazole

In this study, magnetic (Fe)-loaded biochar was successfully prepared by a simple impregnation pyrolysis method. Meanwhile, its degradation capability and mechanism for typical antibiotic metronidazole (MNZ) were systematically investigated under different conditions. The characterization of the synthesized material showed that the specific surface area, pore diameter, and pore volume changed significantly. Also, functional groups and metal element Fe were introduced on the surface of the biochar, leading to its better capability to activate peroxymonosulfate (PMS). The degradation experiments showed that the removal of MNZ in the Fe-BC/PMS system can reach up to 95.3% in 60 min under optimal conditions. Free-radical capture experiments showed that there were several active species of •OH, SO4•−, •O2−, and 1O2 present in the catalyst to synergistically degrade MNZ, among which SO4•− played a major role; it was also found that the material can be easily recycled and was still effective after several uses. Further, the main degradation pathways of MNZ include nitrohydroxylation, hydroxyethyl functional group deletion, carboxylation of the amino functional group of •OH, demethylation, oxidation, and carboxylation. It is obvious that the synthesized magnetic-loaded biochar, Fe-BC, generated from waste rape straw crops, shows high catalytic performance in pollutant degradation, providing an insight into the recycling potential of waste biomass in the catalytic field for pollutant removal.

One-pot synthesis of NiCo-phyllosilicate supported on zeolite for enhanced degradation of antibiotic contaminants

The overuse of antibiotics currently results in the presence of various antibiotics being detected in water bodies, which poses potential risks to human health and the environment. Therefore, it is highly significant to remove antibiotics from water. In this study, we developed novel rod-like NiCo-phyllosilicate hybrid catalysts on calcined natural zeolite (NiCo@C-zeolite) via a facile one-pot process. The presence of the zeolite served as both a silicon source and a support, maintaining a high specific surface area of the NiCo@C-zeolite. Remarkably, NiCo@C-zeolite exhibited outstanding catalytic performance in antibiotic degradation under PMS activation. Within just 5 min, the degradation rate of metronidazole (MNZ) reached 96.14%, ultimately achieving a final degradation rate of 99.28%. Furthermore, we investigated the influence of catalyst dosage, PMS dosage, MNZ concentration, initial pH value, and various inorganic anions on the degradation efficiency of MNZ. The results demonstrated that NiCo@C-zeolite displayed outstanding efficacy in degrading MNZ under diverse conditions and maintained a degradation rate of 94.86% at 60 min after three consecutive cycles of degradation. Free radical quenching experiments revealed that SO•− 4 played a significant role in the presence of NiCo@C-zeolite-PMS system. These findings indicate that the novel rod-like NiCo-phyllosilicate hybrid catalysts had excellent performance in antibiotic degradation.

Pyrolysis temperature effect on the efficacy of biochar/CuNi composite catalysts for emerging pollutant degradation

Sugarcane pulp bagasse biochar (SCPBB) was produced through pyrolysis from 500 to 900 °C under a nitrogen atmosphere, and their SCPBB/CuNi composites was produced through wetness impregnation with copper and nickel salts followed by pyrolysis. The impact of pyrolysis temperature on SCPBB and SCPBB/CuNi for physic-chemical properties was evaluated. SEM images that spherical bimetallic CuNi nanoparticles were evenly dispersed on the surface of the biochar matrix, and the size of the nanoparticles increased with increasing temperature. In particular, when the pyrolysis temperature is higher than 700 °C, the nanoparticles on the surface exhibit novel structures that are partially embedded or completely enclosed within the porous biochar matrix. FT-IR ATR and Raman spectra proved that SCPBB materials contain abundant surface functional groups and carbonaceous structures, which were preserved by the introduction of metal nanoparticles. TGA demonstrated SCPBB-500 biochar started to lose mass quickly first, followed by SCPBB-700 and finally SCPBB-900, and the weight residues of SCPBB/CuNi increased by 30 %-34 % compared with SCPBB. In addition, the catalytic performance of the synthesized material was explored for the degradation of malachite green (MG) representing dye molecules, Amoxicillin (AMX) representing pharmaceuticals, and methyl-parabens (MP) representing personal care products contaminants. Each SCPBB/CuNi sample showed catalytic degradation performance under Advanted oxidation processes (AOPs), among which the SCPBB/CuNi catalyst obtained by pyrolysis temperature 500 °C performed best. Hence, SCPBB/CuNi demonstrates promising potential as a multifunctional catalyst for diverse environmental pollutants in wastewater treatments.

Preparation of CeO2 Supported on Graphite Catalyst and Its Catalytic Performance for Diethyl Phthalate Degradation during Ozonation

Catalysts for the efficient catalytic decomposition of ozone to generate reactive free radicals to oxidize pollutants are needed. The graphite-supported CeO2 catalyst was optimally prepared, and its activity in ozonation was evaluated using the degradation of diethyl phthalate (DEP) as an index. The stability of CeO2/graphite catalyst and the influence of operating conditions on its catalytic activity were investigated, and the mechanism of CeO2/graphite catalytic ozonation was analyzed. CeO2/graphite had the highest catalytic activity at a Ce load of 3.5% and a pyrolysis temperature of 400 °C with the DEP degradation efficiency of 75.0% and the total organic carbon (TOC) removal efficiency of 48.3%. No dissolution of active components was found during the repeated use of CeO2/graphite catalyst. The ozone dosage, catalyst dosage, initial pH, and reaction temperature have positive effects on the DEP degradation by CeO2/graphite catalytic ozonation. The presence of tert-butanol significantly inhibits the degradation of DEP at an initial pH of 3.0, 5.8, or 9.0, and the experimental results of the •OH probe compound pCBA indicate that the CeO2/graphite catalyst can efficiently convert ozone into •OH in solution. The DEP degradation in the CeO2/graphite catalytic ozonation mainly depends on the •OH in the bulk solution formed by ozone decomposition.

Synergistic oxidation of humic acid treated by H2O2/O3 activated by CuCo/C with high efficiency and wide pH range

Combination of oxidation processes are one of the most promising humic acid treatment technologies. Single oxidant or even two oxidants in advance oxidation process can hardly achieve satisfactory removal efficiency of refractory organic matter, mainly humic acid, in the treatment process of reverse osmosis concentrates from landfill leachate. To solve this problem, this study investigated the synergistic degradation of Humic acid (HA) using a Cu and Co supported on carbon catalyst (CuCo/C) in a Hydrogen peroxide (H2O2) with ozone (O3) system. The catalyst was characterized by performing SEM, XRD, BET, XPS and FTIR technologies. UV–vis spectra, 3D Excitation Emission Matrix Spectra (3D-EEM) and gas chromatography-mass spectrometry (GC–MS) were applied for exploring degradation mechanism of HA. To further understand the oxidation mechanism, electron paramagnetic resonance (EPR) was used to evaluate the generation of hydroxyl (·OH) and superoxide radicals (O2·-). As a result, CuCo/C catalyst possessed stable catalytic performance for HA degradation with a wide pH range from 5 to 8, while T = 40 °C，catalyst dosage of 2.4 g/L，O3 intake rate of 0.15 g/min and H2O2 dosage of 1.92 mL/L, the degradation rate of total organic carbon (TOC) achieved 40–46.5 mg·L−1min−1. As affirmed by the EPR, ·OH and O2·- were effectively generated with addition of the CuCo/C catalyst. Degradation performance of UV254 proved that the catalytic activity can still be maintained above 95% with removal rate of 82% after 5 cycles reuse. GC-MS shows that the oxidation products mainly consist of amide, benzoheterocyclic ring and carboxylic acid. This work promotes an effective method for degrading HA, which has the potential for satisfactory application in landfill leachate.

Improved piezo-photocatalysis for aquatic multi-pollutant removal via BiOBr/BaTiO3 heterojunction construction

Piezo-catalysis is a green and effective method for degrading rich and obstinate molecules in wastewater. Yet, the piezo-catalytic performance of frequently-used barium titanate (BTO) is still limited for practical applications, thus it is crucial to construct high-efficiency BTO-based catalysts. Herein, BiOBr/BTO heterojunction-based piezo-photocatalysts were successfully prepared using the chemical precipitation method, and an internal electric field was established via ultrasound to promote the separation of photogenerated electron-hole pairs through the synergistic effect of piezocatalysis and photocatalysis. Transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy were utilized to characterize the heterojunction. The degradation performance of Rhodamine B (RhB) by BiOBr/BTO is the best among various pollutants, giving a reaction rate constant up to 20.839 × 10−2 min−1, exceeding numerous previously reported catalysts. In addition, the piezo-photocatalytic reaction rate of BiOBr/BTO for Methyl Orange was 9.298 × 10−2 min−1, ≈ 3.3 times than those of pure BTO (2.806 × 10−2 min−1), and also ≈ 15.9 times and 3.3 times than those of single photocatalysis (0.585 × 10−2 min−1) or piezocatalysis (2.848 × 10−2 min−1). Importantly, the BiOBr/BTO heterojunction demonstrates excellent catalytic degradation performance for a broad range of pollutants (e.g., dyes and antibiotics) and their mixtures, as well as favorable cycling stability and repeatability with changed environmental conditions, displaying applicability in actual wastewater treatment. The possible degradation pathways of RhB were analyzed by liquid chromatography-mass spectrometry. The present work supplies a feasible strategy for the preparation of high-efficiency piezo-photocatalytic BTO-based heterojunctions, which can guide other composites for environmental remediation.

ZnAl LDH-based Derivative Materials as Photocatalysts: Synthesis, Characterization, and Catalytic Performance in Tetracycline Degradation

Layered Double Hydroxide (LDH)-derived materials exhibited different characteristics from LDH precursors. The conversion of ZnAl LDH into its derivative material has been carried out to find the best catalyst for TC degradation. ZnAl (LDH)-based catalysts in this study have been effectively synthesized using coprecipitation, calcination, and restacking procedures. ZnAl Layered Double Oxide (LDO) is derived from the calcination of ZnAl LDH at 500°C. ZnAl LDH was also modified by adding Garcinia mangostana pericarp extract (GME). XRD, FT-IR, UV-DRS, and SEM-EDX were used to investigate the synthesized catalyst. ZnAl LDH exhibited the typical LDH FT-IR spectra, whereas ZnAl LDO showed metal oxide-like spectra, and the ZnAl-GME composite displayed the combination spectra of precursor material. The ZnAl LDH XRD diffraction pattern exhibited the attributes of a layered material, whereas the other three catalysts did not. Calcination destroyed the layered structure of ZnAl LDH, whereas the addition of GME to LDH and LDO generated a single-layered composite. The modified ZnAl-GME composite showed a decrease in both particle size and bandgap energy. At an ideal pH of 5, the synthesized catalyst was used in a batch system photodegradation of 5 mg/L Tetracycline (TC), employing solar light irradiation. ZnAl LDO holds the most significant catalytic activity and structural stability through the fifth regeneration cycle, degraded TC up to 100% in 90 minutes.

Rational Design and Synthesis of Fe-Doped Co-Based Coordination Polymer Composite Photocatalysts for the Degradation of Norfloxacin and Ciprofloxacin.

The solar light-responsive Fe-doped Co-based coordination polymer (Fe@Co-CP) photocatalyst was synthesized under mild conditions. [Co(4-padpe)(1,3-BDC)]n (Co-CP) was first constructed using mixed ligands through the hydrothermal method. Then, Fe was introduced into the Co-CP framework to achieve the enhanced photocatalytic activity. The optimal Fe@Co-CP-2 exhibited excellent catalytic degradation performance for norfloxacin and ciprofloxacin under sunlight irradiation without auxiliary oxidants, and the degradation rates were 91.25 and 92.66% in 120 min. These excellent photocatalytic properties were ascribed to the generation of the Fe-O bond, which not only enhanced the light absorption intensity but also accelerated the separation efficiency of electrons and holes, and hence significantly improved the photocatalytic property of the composites. Meanwhile, Fe@Co-CP-2 displayed excellent stability and reusability. In addition, the degradation pathways and intermediates of antibiotic molecules were effectively analyzed. The free radical scavenging experiment and ESR results confirmed that •OH, •O2-, and h+ active species were involved in the catalytic degradation reaction; the corresponding mechanisms were deeply investigated. This study provides a fresh approach for constructing Fe-doped Co-CP-based composite materials as photocatalysts for degradation of antibiotic contaminants.

Phase engineering induces electron redistribution to turn periodate activation activity of MoS2

MoS2-based materials are promising in the field of wastewater treatment. However, the potential application and intrinsic mechanism of MoS2-driven periodate (PI) remains unclear. Here, the MoS2 materials with different 1T/2H ratios, which were characterized by XRD, Raman and XPS were synthesized. The MoS2/PI system could signally promote oxytetracycline (OTC) degradation under dark conditions and 1T/2H ratio of MoS2 has a noticeable effect on the catalytic performance. Specially, the kobs of L-1T-MoS2 (50% 1T phase) was 1.59 and 3.62 times of H-1T-MoS2 (∼74% 1T phase) and 2H-MoS2 (100% 2H phase). The results of quenching experiments, EPR, EIS, I-t and Tafel polarization curves showed that •OH and 1O2, rather than O2•−, H2O2, IO3•, high-valent oxide oxidation and electron transfer, played important roles in MoS2/PI systems. XPS analysis and DFT calculations revealed that Mo was the primary site and phase engineering increased the electron density of Mo sites in MoS2, thereby regulating the activation of PI. These results would enrich understandings on phase engineering of MoS2 to turn its catalytic performance for OTC degradation.

Mn-regulated CuFe2O4 spinel based active component continuous exsolution catalyst for long-term degradation of tetracycline

The development of catalysts with fast reaction rates and long service life remains a significant challenge in advanced oxidation processes. The research applied the property that Mn could occupy both tetrahedral and octahedral sites in the spinel structure. By adjusting Mn composition engineering in CuFe2O4, it could regulate the proportion of active components in spinel constituents and form the hybrid catalyst of Mn-doped CuFe2O4/CuO. CuFe2O4/CuO biphasic interface caused lattice distortion, effectively enhancing the interface interaction, which was conducive to the gradual exsolution and redeposition of the active component CuFe2O4 during the catalytic reaction process, thereby prolonging the service life of the catalyst. Within 30 min, the removal rate of tetracycline hydrochloride was 97.3%, while peroxymonosulfate (PMS) stoichiometric efficiency was 0.12. The degradation effect of the powder catalyst only decreased by 7.3% after 6 cycles. In the self-made fixed bed, the mass ratio of sodium alginate solidified catalyst to sewage treatment capacity could reach 1:33000. These results indicated that Mn doping could effectively improve the catalytic degradation performance of CuFe2O4 and prolong the service life of the catalyst by forming a two-phase interface. Furthermore, sodium alginate curing catalysts could provide new insights into the industrial application of catalysts.