Degradation Rate Research Articles

Controlled localization of graphene oxide to improve barrier, biodegradation and mechanical properties of PBAT/EVOH

AbstractIncorporating graphene oxide (GO) with controlled localization into poly(butylene adipate‐co‐terephthalate) (PBAT) blends with poly(ethylene vinyl alcohol) (EVOH) aimed to improve barrier properties, biodegradability, and mechanical strength of PBAT. The PBAT/EVOH/GO nanocomposites containing 0 to 1 wt% of GO were prepared by a reactive mixing process in internal mixer. Microscopic images confirmed that the GO nanoplatelets are mainly localized in PBAT phase and then at the interface, contrary to the thermodynamic affinity of GO toward EVOH. The reactive nature of PBAT/EVOH/GO nanocomposites was confirmed via time‐sweep rheological studies where specific changes were observed in melt viscosity over time. The results of microscopic studies, rheometry, tensile test, and dynamic mechanical thermal analysis (DMTA) confirmed that localizing GO at the interface establishes strong interactions between PBAT and EVOH. By the addition of 0.75 wt% GO, tensile and yield strength were improved by 19% and 45%, respectively. Increasing GO significantly increased the hydrolysis degradation rate of the nanocomposites. Furthermore, the addition of GO considerably decreased the oxygen and water vapor permeability of the blends by up to 40% at 1 wt% GO.

Synergistic Degradation of Methylene Blue by Hydrodynamic Cavitation Combined with Hydrogen Peroxide/Vitamin C System.

In this study, a new combined process of hydrodynamic cavitation (HC) and a hydrogen peroxide/vitamin C (H2O2/Vc) system was proposed for the degradation of methylene blue (MB) in wastewater. An impact-jet hydraulic cavitator was used as the cavitation generation equipment, and H2O2/Vc was selected as a homogeneous oxidation system. The degradation characteristics of MB were investigated. The results showed that the degradation effect of HC in combination with the H2O2/Vc system was more effective than that of the individual HC or H2O2/Vc system. A maximum degradation rate of 87.8% was achieved under the following conditions: H2O2 concentration of 0.03 mol/L, Vc concentration of 0.021 mol/L, inlet pressure of 0.3 MPa, initial solution concentration of 4 μmol/L, solution volume of 150 mL, and reaction time of 10 min. The synergy index was 1.615, indicating a synergistic effect between the HC and H2O2/Vc system. The data of the hydroxyl radical (·OH) yield under the conditions of HC, the H2O2/Vc system, and the HC + H2O2/Vc system were fitted and analyzed. A correlation equation for ·OH yield was established, further revealing the synergistic mechanism of the HC and H2O2/Vc system. The intermediate products of MB degradation were detected based on LC-MS, and three possible degradation pathways of MB degradation were proposed. The combined process of HC and H2O2/Vc systems exhibited relatively low energy efficiency and operating cost, indicating that it was in line with the development direction of wastewater treatment.

Highly concentrated collagen/chondroitin sulfate scaffold with platelet-rich plasma promotes bone-exposed wound healing in porcine.

In the case of wounds with exposed bone, it is essential to provide not only scaffolds with sufficient mechanical strength for protection, but also environments that are conducive to the regeneration of tissues and blood vessels. Despite the excellent biocompatibility and biodegradability of collagen and chondroitin sulfate, they display poor mechanical strength and rapid degradation rates. In contrast to previous methodologies that augmented the mechanical properties of biomaterials through the incorporation of additional substances, this investigation exclusively enhanced the mechanical strength of collagen/chondroitin sulfate scaffolds by modulating collagen concentrations. Furthermore, platelet-rich plasma (PRP) was employed to establish optimal conditions for vascular and tissue regeneration at the wound site. High-concentration collagen/chondroitin sulfate (H C-S) scaffolds were synthesized using high-speed centrifugation and combined with PRP, and their effects on endothelial cell proliferation were assessed. A porcine model of bone-exposed wounds was developed to investigate the healing effects and mechanisms. The experimental results indicated that scaffolds with increased collagen concentration significantly enhanced both tensile and compressive moduli. The combination of H C-S scaffolds with PRP markedly promoted endothelial cell proliferation. In vivo experiments demonstrated that this combination significantly accelerated the healing of porcine bone-exposed wounds and promoted vascular regeneration. This represents a promising strategy for promoting tissue regeneration that is worthy of further exploration and clinical application.

Identification of a Fomitopsis pinicola from Xiaoxing’an Mountains and Optimization of Cellulase Activity

Brown-rot fungi are large fungi that can decompose the cell walls of wood; they are notable for their secretion of diverse and complex enzymes that synergistically hydrolyze natural wood cellulose molecules. Fomitopsis pinicola (F. pinicola) is a brown-rot fungus of interest for its ability to break down the cellulose in wood efficiently. In this study, through a combination of rDNA-ITS analysis and morphological observation, the wood decay pathogen infecting Korean pine (Pinus koraiensis Siebold and Zucc.) was identified. Endoglucanase (CMCase) and β-glucosidase were quantified using the DNS (3,5-Dinitrosalicylic acid) method, and the cellulase activity was optimized using a single-factor method and orthogonal test. The results revealed that the wood-decaying fungus NE1 identified was Fomitopsis pinicola with the ITS accession number OQ880566.1. The highest cellulase activity of the strain reached 116.94 U/mL under the condition of an initial pH of 6.0, lactose 15 g·L−1, KH2PO4 0.5 g·L−1, NH4NO3 15 g·L−1, MgSO4 0.5 g·L−1, VB1 0.4 g·L−1, inoculated two 5 mm fungal cakes in 80 mL medium volume cultured 28 °C for 5 days. This laid a foundation for improving the degradation rate of cellulose and biotransformation research, as well as exploring the degradation of cellulose by brown rot fungi.

Explore synergistic catalytic ozonation by dual active sites of oxygen vacancies and defects in MgO/biochar for atrazine degradation

The design of highly efficient and sustainable catalytic materials is highly desirable for the development of advanced oxidation process (AOPs) used in water treatment. This study used waste litchi shells as precursors to prepare biochar (BC). The composite material (BC@MgO) was synthesized upon loading magnesium oxide (MgO) on BC and used for the heterogeneous catalytic ozonation (HCO) of atrazine (ATZ). BC@MgO exhibited an ATZ degradation rate of 92.8 % over 30 min under the optimal degradation conditions and maintained its good catalytic performance over four cycles, exhibiting excellent catalytic activity and stability. Characterization and experimental results revealed the synergistic effect of oxygen vacancies (OVs) and BC defects on the adsorption and decomposition of ozone molecules. The exposure of the surface magnesium ions was promoted in the presence of OVs on MgO, allowing water molecules to dissociate on the surface magnesium sites to form surface hydrated hydroxyl groups. Biochar defects accelerated the adsorption of ozone molecules by virtue of its higher surface energy. These active sites led to the substantial generation of reactive oxygen species (ROS), which possessed strong oxidizing ability and thereby participated in the degradation of ATZ. In addition, the possible degradation pathways and toxicity of ATZ were evaluated. Overall, this design provided a novel approach to the comprehensive utilization of waste lychee shells, as well as an efficient, stable, and green catalyst for the development of AOPs used in water treatment.

TiO2 nanotubes zeolite nanophotocatalyst performance efficacy toward the photocatalytic degradation of triclocarban in bathroom greywater

Triclocarban (TCC) is persistent in aquatic environments, where it can remain stable for extended periods. It can cause long-term exposure, potentially affecting ecosystems and human health through contaminated fish or water. Therefore, this study aims to investigate the degradation of TCC in bathroom greywater by the application of TiO2 nanotubes coated with zeolite (TNZPC) in photocatalytic degradation. Electrochemical anodization (ECA) and electrophoretic deposition (EPD) were applied to form TNZPC. Field Emission-Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), and X-ray Fluorescence (XRF) verified the characterization of TNZPC accordingly and the degradation kinetics of TCC followed the pseudo-first-order model of Hinshelwood. The highest degradation rate, reaching 95.2%, was observed at pH 11, while the lowest rate was at pH 3, with a degradation efficiency of only 72.6% after 60 minutes of irradiation with utilization of 0.75 cm2 of TNZPC. The mechanism study has verified eleven intermediate products were produced during TCC degradation by the process of oxidation, ozonation, hydroxyl radical (*OH), and dichlorination. The study suggests that finding the optimum conditions such as photocatalyst modification, cationic material, light sources, TCC initial concentration, pH, and TNZPC size play crucial roles in significant TCC photocatalytic degradation.

Barium titanate/ZnAl-layered double hydroxide catalysts for piezoelectrically enhanced photocatalytic degradation of coexisting pollutants and antibiotic resistance genes

Composite materials consisting of BaTiO₃/ZnAl-layered double hydroxide (LDH) were synthesized utilizing a combination of self-assembly and hydrothermal techniques, displaying outstanding piezoelectric characteristics. When subjected to ultrasonic vibration and visible light (VSL) irradiation, these composites demonstrated superior piezoelectric photocatalytic capabilities, achieving degradation rates of 99 % for NTP and a complete 100 % for TC within a span of 45 minutes. The presence of ultrasonic vibration induces polarized electric fields within the ZnAl-LDH and BaTiO₃ components. These fields support the maintenance of the intrinsic electric field strength across the heterojunction interfaces, facilitating the expedited migration of photogenerated carriers. Consequently, this enhances the efficiency of carrier separation and fosters a synergistic catalytic effect attributed to dual piezoelectricity when exposed to VSL. This investigation highlights the potential of piezoelectric photocatalysis in efficiently removing pollutants, suggesting its applicability in the treatment of municipal wastewater and sterilization processes, and offers innovative perspectives for advancing piezoelectric photocatalyst development.

Improving hydrolysis and acidification by regulating the oxygen status and solid content of lignocellulosic waste: Emphasis on the unsealed environment and harnessing the potential of microbial communities

The recalcitrant nature of lignocellulosic raw materials poses a challenge for current biogas plant operations, where hydrolysis and acidification (HA) are the rate-determining steps. To explore the HA balance and microbial mechanisms according to oxygen status and in conditions with relatively high solid content, we made a simple change to build an unsealed reactor. We found that the hemicellulose degradation rate increased by 149.3 % under unsealed conditions. Under microaerobic conditions (Mi), HA with more than 10 % total solid (TS) content exhibited a carbon loss rate of < 10 % in the first 7 days. In the 15 % TS Mi treatment, the organic acid conversion coefficient was 0.04, and the concentration increased to 7.4 g/L within 2 days. A high solid content was the key factor for ensuring efficient organic acid production in the early stage, whereas Mi affected the middle stage. Multiple methods revealed that abundant Prevotella and Clostridium, as well as rare Bifidobacterium, Sporacetigenium, and specific bacteria, had substantial effects on efficient organic acid production and HA balance. The correlation with Mi was 0.57–0.83. The abundance of hemicellulase genes increased by 18.41 %, and the abundance of pyruvate kinase in Mi increased by 15.55 % compared with the sealed condition, demonstrating that Mi can provide complementary advantages in the HA process. The findings in this study improved the operational quality of conventional HA and anaerobic digestion.

Visible light-driven catalytic degradation of organic pollutants by S-scheme heterojunction Bi4O5I2/NaNbO3 enhanced by piezoelectric effect

The piezoelectric photocatalytic system can harness mechanical energy and carriers to degrade water pollution. Utilizing strong piezoelectric materials coupled with photocatalysts effectively addresses the recombination of photogenerated carriers. In this study, Bi4O5I2, which responds to both visible light and piezoelectric stimuli, was synthesized by a solvothermal method. It was then further modified with the piezoelectric material NaNbO3 to create a dual piezoelectric-responsive visible photocatalytic material Bi4O5I2/NaNbO3. Under the influence of an internal electric field and visible light irradiated induced by periodic ultrasonic vibration, the degradation rates of ARB and HCl-TC were exceeded 90 % within 90 min. The piezoelectric effect induced by ultrasonic vibration provided a robust internal electric field, significantly enhancing the separation of photoexcited carriers and thereby improving the catalytic activity of Bi4O5I2/NaNbO3. This work advances the effective purification of water pollution and offers valuable insights for developing efficient piezoelectric photocatalytic materials.

Elemental Zn modulation of interfacial structure and in situ construction of (FeCoNiCuZn)O high-entropy oxide/ZnO heterojunction for photocatalytic Rhodamine B dyes

In this study, inspired by the lattice distortion effect of HEOs, we adopt a non-equimolar strategy, fixing the molar ratios of Fe, Ni, Cu, and Co while varying the molar ratio x of Zn/(FeNiCuCo) (x=0.25, 0.5, 1.0, 1.5 and 2.0) to synthesize the HEO-x compounds. With an increase in the Zn content, lattice distortion occurred in the spinel phase of the (FeNiCuZnCo)O HEO, resulting in the gradual precipitation of ZnO nanocrystals. The (220) crystal plane of the spinel phase closely connects with the (100), (002), and (101) crystal planes of the ZnO phase, forming nano-heterojunctions. The HEO-1.5 prepared by controlling the Zn element proportion exhibits a high photocatalytic degradation rate of Rhodamine B (RhB) of up to 99.45 %. The kinetic degradation rate of HEO-1.5 is 17 times higher than that of HEO-0.25, attributed to the nano-heterojunctions formed by the spinel phase and ZnO phase, facilitating effective separation of photogenerated electron-hole pairs, promoting the generation of active free radicals, and rapidly degrading RhB.

Promoting Electricity Production and Cr (VI) Removal Using a Light–Rutile–Biochar Cathode for Microbial Fuel Cells

Microbial fuel cell (MFC) technology holds significant promise for the production of clean energy and treatment of pollutants. Nevertheless, challenges such as low power generation efficiency and the high cost of electrode materials have impeded its widespread adoption. The porous microstructure of biochar and the exceptional photocatalytic properties of rutile endow it with promising catalytic potential. In this investigation, we synthesized a novel Rutile–Biochar (Rut-Bio) composite material using biochar as a carrier and natural rutile, and explored its effectiveness as a cathode catalyst to enhance the power generation efficiency of MFCs, as well as its application in remediating heavy metal pollution. Furthermore, the impact of visible light conditions on its performance enhancement was explored. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analysis validated the successful fabrication of rutile composites loaded with biochar. The maximum current density and power density achieved by the MFCs were 153.9 mA/m2 and 10.44 mW/m2, respectively, representing a substantial increase of 113.5% and 225% compared to the control group. In addition, biochar-supported rutile MFCs showed excellent degradation performance of heavy metal pollutants under light conditions. Within 7 h, the Cr6+ degradation rate reached 95%. In contrast to the blank control group, the removal efficiency of pollutants exhibited increases of 630.8%. The cyclic degradation experiments also showcased the remarkable stability of the system over multiple cycles. This study successfully integrated natural rutile and biochar to fabricate highly efficient cathode photocatalyst composites, which not only enhanced the power generation performance of MFCs but also presented an environmentally sustainable and economically viable method for addressing heavy metal pollution.

One-pot synthesis of FeNi3/FeNiOx nanoparticles for PGM-free anion exchange membrane water electrolysis

Low-temperature anion exchange membrane water electrolysis (AEMWE) is one of the most promising technologies to produce green hydrogen. To date, membrane-electrode assembly (MEA) based on platinum group metal (PGM) electrocatalysts shows higher performance than PGM-free ones. Here, a single and easy synthesis for non-noble metal electrocatalysts (PGM-free) for both hydrogen and oxygen evolution reactions (HER and OER) was developed. Both electrocatalysts consist of FeNi3/FeNiOx nanoparticles obtained through chemical reduction using hydrazine. The electrocatalyst exhibits an overpotential of 210 mV and 234 mV for HER and OER respectively, at a current density of 10 mA cm−2 in 1 M KOH electrolyte, allowing a comparison between mass activity and geometric activity compared to PGM catalysts. In addition to a preliminary electrochemical characterization of the FeNi3/FeNiOx, the electrocatalyst were integrated into a pilot-scale AEMWE at both anode and cathode, which reaches (without iR-correction) 1.72 V and 1.94 V at a current density of 0.4 A cm−2 and 1 A cm−2 respectively at 60 °C. This PGM-free MEA outperforms the one based on Pt/C at cathode and RuO2 at anode with a voltage gap of 284 mV at 1 A cm−2. The aforementioned MEA was tested for 150 h with a discontinuous power profile, in order to get an idea of the possible degradation trends for a future industrial application, the reversible and irreversible voltage losses were calculated resulting in a degradation rate of 886 µV/h. This work demonstrates a simple and scalable synthesis of earth-abundant electrocatalytic materials for high-efficiency AEM water electrolysis.

Fate and transport of ten plant protection products of emerging concern in a coastal lagoon: Application and evaluation of a multimedia level III fugacity model

Multimedia fugacity models are effective tools for studying the environmental behaviour and occurrence of contaminants of emerging concern (CECs) and assessing associated risks, especially when experimental data is limited. These models describe processes controlling chemical partitioning, transport, and reactions in environmental media using mathematical statements based on the concept of fugacity.To aid in identifying and prioritizing CECs for future local monitoring, we present here the application of a level III multimedia fugacity model assuming non-equilibrium between compartments and steady-state conditions. This model estimated predicted environmental concentrations (PECs), persistence, distribution, and transport of ten plant protection products (PPPs) in the Venice Lagoon, a complex coastal environment under high anthropogenic pressure.The model was evaluated through uncertainty and sensitivity analysis using the Monte Carlo approach and by comparing PECs with PPP concentrations measured during four sampling campaigns. Results showed good agreement with field data, with the highest concentrations in water and sediments estimated for glyphosate, followed by imidacloprid, metaflumizone, and triallate. The model indicated accumulation of all investigated PPPs in sediments. For most chemicals, advection outflow and degradation in the water column were the main removal mechanisms, while volatilization was significant only for oxadiazon and triallate.Sensitivity and uncertainty analysis revealed that degradation rates, organic carbon/water partitioning coefficients (KOC), and parameters describing air-water interactions had the strongest influence on the model's results, followed by inputs accounting for sediment sinking and resuspension. The lack of data on PPP degradation in brackish waters accounted for most of the uncertainty in model results.This work shows how a relatively simple multimedia model can offer new insights into the environmental behaviour of PPPs in a complex transitional waterbody such as the Venice lagoon, providing useful data for the identification of the CECs to be prioritised in future local monitoring efforts.

Intra-articular injection of platinum nanozyme-loaded silk fibroin/pullulan hydrogels relieves osteoarthritis through ROS scavenging and ferroptosis suppression

Reactive oxygen species (ROS)-mediated ferroptosis plays a critical role in the development of osteoarthritis (OA). Consequently, it is speculated that anti-ferroptosis agents could represent a novel therapeutic strategy for managing OA. In this study, a hydrogel incorporating platinum (Pt) nanozyme was synthesized by dispersing Pt nanoparticles (NPs) within a matrix of silk fibroin (SF) and oxidized pullulan (oxPL). This hydrogel allows for a substantial and sustained release of up to 30 days. The gelation time (from 140.3 ± 42.3 s to 460.0 ± 40.0 s), swelling capacity (from 57.7 ± 3.8 % to 24.0 ± 7.0 %), and degradation rate (from 60.3 ± 4.7 % to 32.0 ± 4.6 %) of the hydrogels can be modulated by adjusting the Pt NP content. The Pt@SF/oxPL hydrogel effectively eliminates ROS due to its catalase-like and superoxide dismutase-like enzymatic properties. In vitro studies demonstrated that Pt@SF/oxPL efficiently mitigated the process of ferroptotic cell death in chondrocytes. More critically, intra-articular administration of Pt@SF/oxPL showcased therapeutic advantages by both protecting and stimulating the regeneration of cartilage throughout the progression of OA. Collectively, this study suggests that Pt@SF/oxPL hydrogels could potentially serve as an effective treatment for OA, presenting a novel nanozyme-based therapeutic approach for this condition.

Surface plasmon effect combined with S-scheme charge migration in flower-like Ag/Ag6Si2O7/Bi12O17Cl2 enables efficient photocatalytic antibiotic degradation

Developing robust photocatalysts for photocatalytic environment decontamination is significant and challenging. A novel flower-like S-scheme Ag/Ag6Si2O7/Bi12O17Cl2 (AASO/BOC) plasmonic heterojunction is successfully constructed using a facile route, and applied in photocatalytic destruction of tetracycline hydrochloride (TC) and levofloxacin (LEV) under visible-light irradiation. Benefiting from the combination of S-scheme Bi12O17Cl2/Ag6Si2O7 heterojunction and the plasma Ag, the production and separation of photogenerated carriers are dramatically enhanced. Consequently, compared to the pristine Bi12O17Cl2 and Ag6Si2O7, AASO/BOC displays superior photocatalytic degradation performance. Impressively, the photocatalytic TC degradation rate of AASO/BOC-2 reaches 0.0260 min−1, which is approximately 3.1, 14.4 and 2.0 times those of Bi12O17Cl2, Ag6Si2O7 and Bi12O17Cl2/Ag6Si2O7, respectively. Moreover, the photocatalytic mechanism of TC degradation is studied in depth via various techniques, and the photogenerated OH, O2− and h+ collectively contribute to the photo-degradation of TC. This research puts forward a neoteric approach to designing plasmonic S-scheme photocatalysts for environmental applications.

Differential Effects of Ephemeral and Stable Predator Chemical Cues on Spider Antipredator Behaviour

AbstractSemiochemicals left by predators in their foraging area can be utilised by prey to avoid predation. The range of predators’ chemical cues with contrasting degradation rates might provide information of different quality, potentially allowing prey to differentiate between the immediate and the longer-term presence of predators in a location. So far, knowledge about the roles of volatile versus stable chemical cues in informing predation risk is limited. We here seek to disentangle the role of ephemeral trail pheromones compared to persistent cuticular hydrocarbons of ants (predators) on the antipredator behaviour of juvenile spiders (prey), with the expectation that volatile semiochemicals induce avoidance behaviour in spiders at a higher rate compared to stable cues. We allowed the spiders to choose between sites with and without ant cues separately for volatile trail pheromones and stable hydrocarbons. Unexpectedly, spiders avoided the presence of persistent cuticular hydrocarbons more clearly than the highly volatile trail pheromone. This underscores the widespread impact of these stable cues on the avoidance behaviour of potential intraguild prey. The response to trail pheromones was unclear, possibly because spiders always encounter these cues simultaneously with visual and vibratory cues from ants; hence, trail pheromones may not contain any additional information, hindering the evolution of the ability to detect them.

Flower-like nickel oxide nanostructures: Superior ammonia gas sensing and efficient dye removal behavior under UV–visible light illumination

In this study, we fabricated the NiO nanostructures using a straightforward solvothermal technique. The NiO nanoparticles were characterized using various analytical techniques. The FESEM images clearly show the flower-like structure of NiO nanoparticles. These nanostructures were then employed as a sensor to detect the presence of highly toxic ammonia (NH3) gas. The flower-shaped nanostructures of NiO played a vital role in improving sensing performance. Moreover, the NiO sensor displayed rapid response to 100 ppm ammonia at room temperature, with responses/recovery times of 40 s/44 s. This research holds promise as a viable approach for effectively sensing and detecting NH3 gas. The NiO exhibited excellent photocatalytic activity and degradation rates of 80% and 84.75% for Methyl orange (MO) and methylene blue dye (MB) respectively under UV-visible light irradiation. The NiO nanoflower remains unaffected after recycling MB dye degradation. This effective photocatalytic performance might be due to the formation of flower-like morphology. This underscores the potential of NiO as a promising candidate for applications in environmental and healthcare safety applications.

Introducing oxygen cacancies to tune Cu2O by Sn ion-doped for high-effective photocatalytic degradation of norfloxacin in wastewater

Photocatalytic materials have attracted considerable attention owing to its positive environmental impact and efficiency in wastewater treatment. Herein, tin (Sn)-doped copper oxide (Cu2O) photocatalysts were successfully synthesized via a facile hydrothermal approach. The doping of Sn ions into the Cu2O lattice promoted the formation of more oxygen vacancies, which increased the separation efficiency of photogenerated carriers and enhanced photocatalytic activity. Moreover, the presence of Sn ions enhanced light absorption and the specific surface area of Cu2O, and reduced photogenerated carriers recombination. The synergistic effect of the abovementioned advantages, induced excellent photocatalytic activity to the as-prepared catalysts. Tin chloride (30 mg)-doped Cu2O showed optimal photocatalytic properties with the highest norfloxacin degradation rate of 83.9 % in 140 min under visible light irradiation. Hydroxy radicals played a major role during degradation as demonstrated by the capturing of active species experiment and EPR testing. Photocatalytic mechanisms and possible degradation pathways were proposed based on Perdew-Burke-Ernzerhof and high-performance liquid chromatography-mass spectrometry techniques. The toxicity analyses of the intermediates proved their low toxicity. Repeated cycling experiments confirmed the excellent stability of the catalysts. This work provides a feasible strategy for fabricating high-performance Cu2O-based photocatalysts.

Revealing the vital role of sulfur site on the surface of pyrite in 1O2 formation for promoting ciprofloxacin degradation via peracetic acid activation

Pyrite has been widely utilized to activate oxidants for water treatment, yet the regulation of reactive oxygen species (ROS) by sulfur sites on its surface has been overlooked. In this study, the surface sulfur sites were regulated by thermal modification of natural pyrite in the N2 atmosphere (denoted as P-X, where X represented pyrolysis temperatures ranging from 400 to 700 °C), and these modified pyrites were employed to activate peracetic acid (PAA) for ciprofloxacin (CIP) degradation. The results revealed that the degradation rate of CIP increased as the reduced sulfur content increased, with the P600/PAA system achieving the highest apparent degradation rate (kobs = 0.0999 min−1). Quenching experiments and electron paramagnetic resonance (EPR) analysis identified various ROS involved in the P-X/PAA system, with hydroxyl radical (·OH) and singlet oxygen (1O2) identified as dominant reactive species responsible for CIP degradation. The reduced sulfur sites served as the primary active sites facilitating the conversion of organic radicals (·CH3C(O)OO) into superoxide radicals (·O2−) and 1O2. Furthermore, the P600/PAA system demonstrated robust adaptability under both acidic and neutral pH conditions, efficiently degrading CIP even in the presence of complex matrices such as Cl−, NO3−, SO42−, NH4+, or humic acid (HA) in water bodies, although HCO3− was found to inhibit CIP degradation. This study significantly enhances our understanding of the interaction between reduced sulfur sites and ROS in PAA-based advanced oxidation processes (AOPs), offering a promising technology for efficient antibiotic treatment in water purification.

Improved adsorption and charge transfer capacity by coupling g-C3N4 and NH2-MIL-125 for efficient degradation of sulfamethoxazole in water: Characterization, degradation efficiency, influence factors, and mechanism

Photocatalysis is an advanced oxidation process that shows excellent promise in degrading organic pollutants present in water. However, electrons and holes tend to combine easily during the transfer process, and the adsorption capacity of single-phase photocatalytic materials is weak, resulting in a low degradation rate. Therefore, a new composite semiconductor photocatalyst g-C3N4/NH2-MIL-125 was constructed using a two-step solvothermal method. The morphology, elemental composition, structure, photoelectric properties, and photocatalytic activity of g-C3N4/NH2-MIL-125 were characterized. The photocatalytic degradation of Sulfamethoxazole (SMX) in water was also carried out. Results indicated that g-C3N4/NH2-MIL-125 had been synthesized successfully, and g-C3N4/NH2-MIL-125 had a broader photoresponse range, higher adsorption capacity, and higher separation efficiency of photogenerated carriers. When pH was 4.0 and catalyst dosage was 0.15 g/L, g-C3N4/NH2-MIL-125 showed the highest degradation rate for SMX. It was confirmed that the main active groups in SMX degradation were OH, h+, and O2−. 15 kinds of intermediates of SMX and the possible degradation pathways were identified by high-performance liquid chromatography-mass spectrometry and DFT calculation. Toxicity analysis revealed that the intermediate products have a lower developmental toxicity than SMX. This work demonstrated that g-C3N4/NH2-MIL-125 has great potential in eliminating antibiotics from water.