Main Active Substances Research Articles

MgCo2O4@g‐C3N4 Composite Induced Peroxymonosulfate Activation for Effective Degradation of Tetracycline Under Visible Light

AbstractThe composite Fenton catalyst was prepared by attaching MgCo2O4 to the surface of g‐C3N4 using a one‐pot method after preparing MgCo2O4 through co‐precipitation. The microstructure of the composites was analyzed using X‐ray diffraction (XRD) and other characterization methods. The catalytic activity of the composites towards tetracycline (TC) was studied, and a possible catalytic mechanism was proposed. The experimental results indicate that the degradation of TC by MgCo2O4@g‐C3N4 reached almost 99.0 % within 30 min in the presence of PMS and visible light. The combination of MgCo2O4 and g‐C3N4 improved the absorption of visible light, and the energy level‐matched heterojunction facilitated the separation of photogenerated electrons and holes, accelerating the redox cycle of ≡Co3+/≡Co2+. The free radical quenching experiment confirmed that the main active substances were free radical ⋅O2− and 1O2. The one‐step synthesis of composite catalysts exhibits high catalytic performance and good stability, offering a potential solution for the efficient treatment of tetracycline wastewater.

Synthesis of ZnPc/BiVO4 Z-Scheme Heterojunction for Enhanced Photocatalytic Degradation of Tetracycline Under Visible Light Irradiation

The construction of semiconductor heterojunctions is an effective strategy to improve the photocatalytic degradation efficiency of organic pollutants. Herein, ZnPc/BiVO4 Z-scheme heterojunction was synthesized via a physical mixing method and was used for the photocatalytic degradation of tetracycline (TC) under visible light irradiation. Compared with BiVO4 and ZnPc, the 15ZnPc/BiVO4 sample exhibited improved light absorption capacity, and the electron-hole separation efficiency and redox capacity were enhanced due to the formation of the Z-scheme heterojunction. The 15ZnPc/BiVO4 composite exhibited an optimal TC degradation rate of 83.1% within 120 min. Additionally, 15ZnPc/BiVO4 exhibited excellent stability in cycling experiments, which maintained a high TC degradation rate of 79.5% after four cycles. Free radical trapping experiments indicated that superoxide radicals (O2−) were the main active substances in the photocatalytic degradation of TC.

Application of microorganisms in Panax ginseng: cultivation of plants, and biotransformation and bioactivity of key component ginsenosides.

Panax ginseng is a precious Chinese medicinal plant with a long growth cycle and high medicinal value. Therefore, it is of great significance to explore effective ways to increase its yield and main active substance content to reduce the cost of ginseng, which is widely used in food and clinical applications. Here, we review the key roles of microorganisms in the biological control of ginseng diseases, enhancement of ginseng yield, biotransformation of ginsenosides, and augmentation of ginsenoside bioactivity. The application of microorganisms in P. ginseng faces multiple challenges, including the need for further exploration of efficient microbial strain resources used in the cultivation of ginseng and biotransformation of ginsenosides, lack of microbial application in large-scale field cultivation of ginseng, and unclear mechanism of microbial transformation of ginsenosides. This review provides a deeper understanding of the applications of microorganisms in P. ginseng.

Visible-light-driven photocatalytic for degrading tetracycline wastewater by BiOI/Bi2O3 Z-scheme heterojunction

Direct Z-scheme heterojunctions can exhibit enhanced redox capacity in redox reactions compared to conventional heterojunctions. In this study, BiOI/Bi2O3 Z-scheme heterojunctions were synthesized by a facile co-precipitation and calcination method using BiOI as a precursor, and its photocatalytic activity was investigated by degrading tetracycline antibiotics in aqueous environment. Under visible light, the degradation efficiency of tetracycline reached 80.01 % and the photocatalytic degradation rate constant reached 0.0116 min−1 when the molar ratio of Bi and I in BiOI/Bi2O3 composites was 1:1, which were 2.8 and 4.8 times higher than that of pristine BiOI (0.0041 min−1) and Bi2O3 (0.0024 min−1), respectively. The heterojunctions exposed excellent stability that maintained at 78.80 % after four cyclic tests. The ascendant photocatalytic performance can be attributed to the formation of direct Z-scheme heterojunctions, which improves the separation and transfer efficiency of the photogenerated electron-hole pairs, and ·O2- is the main active substance in the degradation process. This research provides a green and convenient method for preparing photocatalytic heterojunctions, which is conducive to promoting the development of photocatalytic degradation of refractory pollutants under visible light.

Glycyrrhizic Acid Inhibits Hippocampal Neuron Apoptosis by Activating the PI3K/ AKT Signaling Pathway.

Glycyrrhizic acid (GA), one of the main active substances in Glycyrrhiza, has anti-inflammatory, anti-viral, and neuroprotective effects. GA can significantly reduce cerebral infarction size in middle cerebral artery occlusion (MCAO) rats and suppress inflammatory responses. However, the underlying mechanism by which GA protects the neuronal system remains poorly understood. Cell proliferation and viability were tested using CCK-8 and Edu assays. The effects of GA on apoptosis were detected using flow cytometry and Tunel assays. Western blotting was performed to assess protein expression. Behavioral experiments were conducted using the Morris water maze and rotation tests. Infarct size was observed using TTC staining. We report that GA protects neurons by inhibiting apoptosis, mainly through the PI3K/AKT pathway in oxygen-glucose deprivation/reoxygenation (OGD/R) and MCAO rat models. GA increases the viability and proliferation of oxygen- and glucose-deprived hippocampal neurons. Hippocampal neuron apoptosis decreased after GA treatment in vitro and in vivo. Furthermore, we determined that GA treatment increased the active state of PI3K and its downstream protein p-AKT, whereas when using a specific inhibitor of PI3K, Y294002, the levels of p-PI3K and p-AKT decreased. Finally, we showed that GA treatment improved spatial memory and motor coordination in MCAO rats, while TTC staining showed that GA decreased cerebral infarct size in MCAO rats. We reveal that GA protects hippocampal neurons by inhibiting their apoptosis, mainly through the PI3K/AKT signaling pathway.

Tuning the morphology and surface structure of MnOx@GF through Ce for high-efficiency degradation of Rhodamine B by electro-Fenton

Widespread and ineffective dye treatment in aquatic environment leads to serious pollution problems, threatening ecology and human health. Herein, manganese cerium bimetallic oxide cathode material (MnCeOx@GF) was prepared by hydrothermal method combined with calcination, and the electrochemical Fenton degradation performance of a typical dye Rhodamine B (Rh B) was investigated. The results show that the degradation of Rh B by MnCeOx@GF can reach 96.5 % within 2 h in acidic environment and continue to perform effectively after 4 repeated experiments. Combined with SEM and electrochemical test results, it can be seen that the bimetallic composite oxides formed by manganese and cerium on the surface of the support can effectively enhance the catalytic activity of the material, the addition of cerium changes the morphology of manganese oxides and promotes the generation of multiple valence composite oxides of transition metals, and improves the degradation of Rh B. Based on the free radical masking experiments, hydroxyl radical (·OH) is the main active substance in the electro-Fenton degradation process. This work not only provides a way to design and manufacture cathode materials for in situ electrosynthesis of H2O2, but also provides an important reference for improving the reusability of cathodes for sustainable dye wastewater treatment.

Astragalin alleviates oligoasthenospermia via promoting nuclear translocation of Nrf2 and reducing ferroptosis of testis

Oligoasthenospermia (OAS) is a global human developmental disease and the most common type of male infertility. There are currently no sufficiently effective therapeutic strategies for OAS. Wuziyanzong Pill (WZYZP) is a traditional Chinese prescription for the clinical treatment of male infertility, and its efficacy is well known in China. Therefore, due to the complexity of traditional Chinese medicine, the specific mechanism of action of WZYZP on OAS has not been elucidated. Astragalin (AG), one of the main active substances in WZYZP, has good antioxidant effect. The aim of this research is to investigate whether AG, the active substance in WZYZP, can treat OAS by promoting Nrf2 nuclear translocation and inhibiting ferroptosis. The OAS model was established by intraperitoneal injection of cyclophosphamide, and the therapeutic effects of AG and WZYZP on OAS were evaluated by detecting sperm quality, sex hormone levels and testicular pathological changes after intragastric administration of AG and WZYZP. Western blot was used to measure the expression levels of TFR1, SLC7A11, GPX4 and FTH1. The nuclear translocation of Nrf2 was detected by immunofluorescence staining and nuclear/intracellular expression of Nrf2. The results showed that AG could improve sperm quality and serum sex hormone levels in OAS rats, reduce the expression of testicular Fe2+ and TFR1, up-regulate testicular SLC7A11, GPX4 and FTH1, and inhibit testicular ferroptosis. At the same time, AG can promote the expression and nuclear translocation of Nrf2 in the testis of OAS rats. AG can alleviate OAS via promoting nuclear translocation of Nrf2 and inhibiting ferroptosis of testis.

Core-shell structured carbon nanofiber-supported bristlegrass-like conductive metal‐organic framework Cu3(HHTP)2 nanorod arrays for electrochemical and colorimetric dual-mode detection of dopamine in serum

Dopamine (DA) is a central neurotransmitter that plays a crucial role in human metabolism. Its precise detection is of great importance in disease diagnosis. Compared with single-signal detection methods, colorimetric and electrochemical dual-signal outputs can self-validate the measured data and counteract interference effects, which is expected to provide more reliable detection results. In this paper, carbon nanofiber-supported 3D bristlegrass-like π-conjugated conducting metal–organic frameworks (cMOF) Cu3(HHTP)2 nanorod arrays (Cu3(HHTP)2 NRAs/CNF) catalyst with core–shell structure are synthesized by electrospinning and solvothermal reaction. The obtained catalyst possesses remarkable peroxidase-like activity which can catalyze the colorless 3,3′,5,5′ −tetramethylbenzidine (TMB) to blue oxTMB. The mechanism study showes that ·OH radicals are the main active substances. Meanwhile, the core–shell structure between π-conjugated cMOF and CNF can effectively inhibit the aggregation of Cu3(HHTP)2 nanorods and generate more catalytic active sites, resulting in strong electrocatalytic activity of Cu3(HHTP)2 NRAs/CNF. As a result, a novel dual-mode sensor based on colorimetric and electrochemical are constructed for detecting dopamine (DA) with a good linear relationship ranging from 2.5-60 μM and 0.1–106 μM, and the limit of detection (LOD) are 0.27 μM and 10.1 nM (S/N=3), respectively. This study opens up a new idea for the application of cMOF peroxidase-like enzyme in sensing field.

Efficacy of Food Supplement Based on Monacolins, γ-Oryzanol, and γ-Aminobutyric Acid in Mild Dyslipidemia: A Randomized, Double-Blind, Parallel-Armed, Placebo-Controlled Clinical Trial.

The risk of cardiovascular disease (CVD) is approximately doubled in subjects with hypercholesterolemia compared to those with normal blood cholesterol levels. Monacolin K (MK), the main active substance in rice fermented by the Monascus purpureus, acts on cholesterol metabolism. Rice also contains other bioactive compounds such as γ-oryzanol (OZ) and γ-aminobutyric acid (GABA). In a randomized, placebo-controlled, double-blind trial, the efficacy and tolerability of a food supplement (FS) based on an ingredient standardized to contain monacolins (4.5%), OZ, and GABA were evaluated in subjects with mild dyslipidemia. For the duration of the trial, enrolled subjects (n = 44, each group) received the FS or placebo and were instructed to use an isocaloric diet. Compared to the placebo group, after a 3 months of the FS, the mean low-density lipoprotein cholesterol and mean TC values were reduced by 19.3 and 8.3%, respectively, while the mean high-density lipoprotein cholesterol value increased by 29.3%. On average, the subjects shifted from very high to moderate CVD risk. Glucose metabolism and hepatic and renal parameters did not change after the treatment and no adverse events were reported. Guidelines to handle hypercholesterolemia with food supplements in specific clinical settings are needed to better manage mild dyslipidemia.

High efficiency degradation of RhB by MIL-88A(Fe)/MoS2 activated persulfate and its mechanism

MoS2/MIL-88A(Fe) composite catalyst was prepared by in-situ formation method. The material was characterized by SEM, TEM, XRD and XPS, and the Rhodamine B(RhB) was activated and degraded by persulfate (PMS). The results showed that M-10/M1:2 had the best degradation effect on RhB, the rate constant was 0.66420 min-1, and the degradation rate could reach 1.89-14 times that of other doped composite catalysts. The SEM results showed that M-10 had the least sulfur content, fewer MoS2 flower layers and more exposed Mo4+ atoms, which improved the electron transfer efficiency and accelerated the degradation reaction. The XPS spectra before and after M-10/M1:2 reaction showed that the REDOX reaction of Fe3+/Fe2+ and Mo4+/Mo6+ on the catalyst surface played an important role in the activation of PMS. The results of free radical capture experiment and ESR test showed that the main active substances in M-10/M1:2/PMS reaction system were SO4•−, 1O2, •O2−, and •OH, which only played a role in the degradation of RhB. Finally, based on the ESR results of M-10/M1:2/PMS system and the changes of Fe and Mo elements in XPS characterization before and after the reaction, the degradation mechanism of M-10/M1:2/PMS system was proposed.

Development of polyvinyl alcohol based active inner coating reinforced with chlorogenic acid and functionalized layered clay for food packaging

Food packaging is developing towards more environmentally friendly polymer matrix and superior active functions. In this study, polyvinyl alcohol (PVA) based active coating incorporating chlorogenic acid (CGA) and CGA functionalized layered clay (LDHs@CGA) was applied to construct polylactic acid (PLA) three-layer active films on fully biodegradable PLA base film. The results indicated that PVA based active coating using dual coating technology (LDHs@CGA/PVA + CGA/PVA) had no visible interface and a uniform thickness, ranging from 4 to 5 μm. When the amount of LDHs@CGA was 1 wt%, the release of CGA in the active intermediate layer (CGA/PVA coating) was limited due to the natural barrier of LDHs@CGA in the controlled release layer (LDHs@CGA/PVA coating), resulting in a decrease in active functions. When the amount of LDHs@CGA reached 3 wt%, the antioxidant (DPPH method), antibacterial (Escherichia coli), and UV absorption (at 335 nm) reached 85.6 %, 87.2 %, and 73.2 %, respectively. This was because in addition to CGA as the main active substance, sufficient amounts of LDHs@CGA can also serve as secondary active substance to supplement the release of CGA. Meanwhile, the addition of LDHs@CGA could significantly improve the gas barrier properties of PVA based active coating, and the barrier to oxygen was much higher than that to water vapor. This study proposes a method of constructing PLA three-layer active films by coating with PVA based active inner coating, which can more effectively and stably exert the active functions for food packaging applications.

Reduced Ag NPs-modified NaTaO3 layer improves photocatalytic degradation and antimicrobial ability through LSPR effect and doping behavior

Reduced Ag NPs modified Ag-doped NaTaO3 layer photocatalysts were prepared using the hydrothermal method. The research investigated the microstructure and degradation ability of composite layer containing Ag-NaTaO3. Various techniques, including SEM,TEM, XRD, UV–Vis and PL analyses, were used for the evaluation. The antibacterial effect of the Ag-NaTaO3 layers on Staphylococcus aureus (S. aureus) before and after modification with reduced Ag NPs was evaluated. The Ag-NaTaO3 composite layer showed stronger degradation effect and bactericidal activity than NaTaO3 under the optimal conditions (Concentration of Ag+-containing solution 0.1 mol/L, reaction temperature 200 ℃, reaction time 3 h). The degradation efficiency of Ag3-NaTaO3 for MB was 87.6 % after 50 min, and the bactericidal inhibition rate was 100 % after 20 min. The degradation process, with electron hole (h+) as the main active substance, conforms to the first-order kinetic with a rate constant (K) value of 0.0310 min−1. The band gaps (Eg) of the calculated pure phase NaTaO3 and Ag3-NaTaO3 are 3.18 eV and 2.75 eV, correspondingly. The fluorescence decay spectra indicate that the average expected lifetimes of Ag3-NaTaO3 composites rounded is 11.45 ns, respectively. The NaTaO3 nano-cubic structure, prepared using Ta2O5 precursor, reduces the grain size, provides more surface active sites, and effectively improves the range of the NaTaO3 photoresponse. AgNO3 solution is used to reduce Ag NPs and carry out doping behavior. The LSPR behavior of Ag NPs and the doping behavior of Ag lower the Schottky barrier that is made up of the metal–semiconductor interface. This ensures that the hot metal electrons are injected into the semiconductors efficiently, improves the electron-hole (h+) separation efficiency, and enhances the photocatalytic activity. The bacterial structure was destroyed through a dual mechanism of reactive oxygen species (ROS) (·OH, ·O2–) and Ag properties, achieving excellent bacterial inhibition. This study proposes a new concept to enhance the photocatalytic performance of NaTaO3 thinfilm materials, which will could have significant applications in the field of wastewater treatment.

Differential characteristics of chemical composition, fermentation metabolites and antioxidant effects of polysaccharides from Eurotium Cristatum and Fu-brick tea

Fu-brick tea (FBT) is predominately fermented by Eurotium Cristatum, FBT polysaccharides (FTPs) and Eurotium Cristatum extracellular polysaccharides (ECPs) are the main active substances in FBT and Eurotium Cristatum, respectively. FTPs was shown to exhibit higher levels of uronic acids, proteins, and polyphenols as compared to ECPs (p < 0.05), contributing to the superior antioxidant activity observed in FTPs. Additionally, FTPs had better water solubility and thermal stability than ECPs. Interestingly, in vitro digestive simulation revealed that FTPs and ECPs resist digestion in the stomach and small intestine. Excitingly, utilizing in vitro fermentation with feces from healthy individuals and type 2 diabetes mellitus (T2DM) patients demonstrated that FTPs and ECPs promote the production of SCFAs. Still, FTPs resulted in greater SCFAs contents than ECPs (p < 0.05). Moreover, FTPs and ECPs fermentation by T2DM patients' fecal microbiota affected different metabolomic pathways. Our findings suggested that FTPs holds great promise for application in functional foods.

Degradation of Bisphenol A Using Self-Excited Oscillating Jets in Synergy with Fenton and Periodate Oxidation: Experimental and Artificial Neural Network Modeling Study

Bisphenol A (BPA) is an environmental endocrine-disrupting compound that is resistant to conventional biological treatment, making it crucial to develop an oxidation process. This study introduces a novel hydrodynamic cavitation (HC) coupled with a Fenton + periodate (PI) oxidation system for the efficient degradation of BPA. By systematically examining the key parameters such as inlet pressure, Fe (II), H2O2, and PI concentration, it was found that HC performed optimally at a pressure of 0.5 MPa. A conversion of 98.14% was achieved within 60 min when the molar ratio of BPA, Fe (II), H2O2, and PI was approximately 1:1:5:1. Further analysis revealed that the gray correlation between H2O2 and PI concentrations on the degradation efficiency was 0.833 and 0.843, respectively, indicating that both of them had significant effects on the degradation process. The free radical quenching assay confirmed the hydroxyl radical (•OH) as the main active substance. Additionally, the toxicity of the degradation intermediates was evaluated using the Toxicity Estimation Software Tool (TEST). An artificial neural network (ANN)-based model was constructed to predict the BPA-degradation process, facilitating precise reagent dosing and providing robust support for the intelligent application of water-treatment technologies.

Mapping Photogenerated Electron-Hole Behavior of Graphene Oxide: Insight into a New Mechanism of Photosensitive Pollutant Degradation.

The use of graphene oxide (GO) photogenerated electron-hole (e-h+) pairs to degrade pollutants is a novel green method for wastewater treatment. However, the interaction between photosensitive pollutants and a GO-light system remains unclear. In this work, the mechanism of degradation of photosensitive pollutant tetracycline (TC) promoted by GO photogenerated e-h+ pairs was studied. Our studies encompassed the determination of TC removal kinetics, analysis of active substances for TC degradation, identification of degradation products, and computational modeling. Clear evidence shows that a new reaction mechanism of enhanced adsorption and induced generation of reactive oxygen species (ROS) was involved. This mechanism was conducive to significantly enhanced TC removal. Kinetic studies showed a first-order behavior that can be well described by the Langmuir-Hinshelwood model. Radical scavenging experiments confirmed that 1O2, •O2-, and holes (h+) were the main active substances for TC degradation. Electron spin resonance analysis indicated that photoexcited TC molecules may transfer electrons to the conduction band of GO to induce the generation of additional ROS. A major transformation product (m/z 459) during TC degradation was identified with liquid chromatography-mass spectrometry. Density functional theory calculation indicated a stronger adsorption between TC and GO under photoirradiation. This mechanism of photo-enhanced adsorption and synergistic induced generation of ROS provides a new strategy for the removal of emerging pollutants in water. Overall, the new mechanism revealed in this work expands the knowledge of applying GO to wastewater treatment and is of great reference value for research in this field.

Jujuboside A through YY1/CYP2E1 signaling alleviated type 2 diabetes-associated fatty liver disease by ameliorating hepatic lipid accumulation, inflammation, and oxidative stress

Non-alcoholic fatty liver disease (NAFLD) was a chronic complication of type 2 diabetes mellitus (T2DM), and this comorbid disease lacked therapeutic drugs. Semen Ziziphi Spinosae (SZS) was the seed of Ziziphus jujuba var. Spinosa (Bunge) Hu ex H.F. Chow, and it could alleviate the symptoms of T2DM patients. As a triterpene saponin, Jujuboside A (Ju A) was the main active substance isolated from SZS and could improve hyperglycemia of diabetic mice. However, it was still unknown whether Ju A has protective effects on T2DM-associated NAFLD. Our study showed that Ju A attenuated T2DM-associated liver damage by alleviating hepatic lipid accumulation, inflammatory response, and oxidative stress in the liver of db/db mice, and high glucose (HG) and free fatty acid (FFA) co-stimulated human hepatocellular carcinomas (HepG2) cells. Along with the improved hyperglycemia and liver injury, Ju A restrained Yin Yang 1 (YY1)/cytochrome P450 2E1 (CYP2E1) signaling in vivo and in vitro. YY1 overexpression intercepted the protective effects of Ju A on T2DM-induced liver injury via promoting hepatic lipid accumulation, inflammatory response, and oxidative stress. While, the blocking effect of YY1 overexpression on Ju A's hepatoprotective effect was counteracted by further treatment of CYP2E1 specific inhibitor diethyldithiocarbamate (DDC) in vitro. In-depth mechanism research showed that Ju A through YY1/CYP2E1 signaling promoted hepatic fatty acid β-oxidation, and inhibited inflammatory response and oxidative stress by activating peroxisome proliferator-activated receptor alpha (PPARα), leading to the improvement of T2DM-associated NAFLD. Ju A might be a potential agent in the treatment and health care of T2DM-associated liver disease, especially NAFLD.

Surface hydroxyl-riched ultrasmall monodispersed CuO nanoparticles for rapid degradation of tetracycline by peroxymonosulfate activation

The activation of peroxymonosulfate (PMS) is viewed as a highly prospective strategy to address antibiotic abuse issues. In this work, surface hydroxyl-riched ultrasmall (3–5 nm) monodispersed CuO nanoparticles (NPs) are firstly applied in the degradation of tetracycline (TC) by PMS activation. The ultrasmall CuO NPs facilitate rapid degradation of TC, achieving approximately 90 % degradation within 1 min and 97 % degradation within 15 min. Furthermore, the degradation efficiency of TC remains 90 % after five cycles. The CuO/PMS system not only exhibits outstanding anti-interference properties toward various anions and organics, and high catalytic activity in a wide pH range, but also could efficiently degrade other common organic pollutants, possessing higher practical application value. Mechanistic experiments elucidated that singlet oxygen (1O2) is the main active substance for TC degradation. This work provides a newly developed and highly effective catalyst for rapid removal of persistent organic contaminants from wastewater by the activation of PMS.

Visible-Light Photocatalytic Degradation Efficiency of Tetracycline and Rhodamine B Using a Double Z-Scheme Heterojunction Catalyst of UiO-66-NH2/BiOCl/Bi2S3.

BiOCl is a promising photocatalyst, but due to its weak visible light absorption capacity and low photogenerated electron-hole pair separation rate, its practical application is limited to a certain extent. In this study, a novel double Z-scheme heterojunction UiO-66-NH2/BiOCl/Bi2S3 catalyst was constructed to broaden the visible light response range and promote high photogenerated hole-electron separation of BiOCl. Its photocatalytic performance is evaluated by dissociating tetracycline (TC) and rhodamine B (RhB) in visible light. The optimal proportion of UiO-66-NH2/BiOCl/Bi2S3 hybrids exhibits the best degradation efficiency of visible light illumination (∼93% in 120 min for TC and ∼98% in 60 min for RhB). The synergistic effect of a large visible light response range and the Z-scheme charge transfer mechanism ensure the excellent visible photocatalytic activity of UiO-66-NH2/BiOCl/Bi2S3. It is proven that h+ and •O2- are the main active substances in the photocatalysis process by active substance capture experiments and electron spin resonance tests. The intermediates and degradation processes are analyzed by high-performance liquid chromatography-mass spectrometry. This study proves that the new UiO-66-NH2/BiOCl/Bi2S3 photocatalyst has great application potential in the field of water pollution degradation and will provide a new idea for the optimization of BiOCl.

New understanding of the main active substances and the promotion mechanism in the degradation of phenol by Fe–C micro-electrolysis systems

ABSTRACT The mechanism of phenol degradation by micro-electrolytic systems can be fully understood by evaluating the oxidation of active substances from the two aspects of phenol bond-breaking and mineralization, and the direction of promoting the generation of active substances is pointed out. In this article, the effects of H2O2, O2-•, ·OH and 1O2 in the degradation of phenol were analyzed using phenol and chemical oxygen demand (COD) removal rates as judgment indicators, respectively. And the addition of C6O8H6 to the micro-electrolysis system was adopted to promote the generation of active substances. The experimental results showed that the active substances which played a dominant effect in the process of phenol bond-breaking and mineralization were changed. While 1O2 is dominant in the bond-breaking of phenol, •OH is dominant in the mineralization of phenol. After adding C6O8H6 (1 mmol/L), the removal rates of phenol and COD were increased by 7.35 and 4.85%, respectively. This was attributed to the autoxidation reaction of C6O8H6 and the continuous supply of H+ while reducing Fe3+ to Fe2+. Additionally, the C6O8H6 regulated the reaction pathway to improve the utilization of H2O2. This study provides a new perspective for the understanding of active substances in micro-electrolysis systems.

Enhanced visible light utilization of BiOI/BiOBr/Bi composite catalytic materials for photocatalytic degradation of TC and reduction of Cr(Ⅵ)

The rational design and construction of semiconductor photocatalytic materials are important significance for efficient utilization of solar energy and enhancement of photocatalytic activity. In this study, composite photocatalytic materials modified with Bi0 on the surface of BiOI/BiOBr heterojunction were successfully constructed based on the current mature electrostatic spinning technology by using solvothermal and in-situ reduction methods. The successful preparation of BiOI/BiOBr/Bi composites was confirmed by a series of characterization methods. The composite photocatalyst was applied to the degradation of pollutants, and by adjusting the addition ratio of different substances, it was found that the photocatalytic composites prepared with the addition of 0.125 mmol NaBH4 and the ratio of I/Br of 3:1 showed the best performance. The degradation efficiency of the catalyst for tetracycline hydrochloride (TC) at 10 mg/L reached 98.4 % after 180 min of visible light irradiation, and the high degradation performance of the material was maintained after five cycles. Meanwhile, the reduction efficiency of the material for Cr(VI) was 98.2 % after 100 min of visible light irradiation. Free radical trapping experiments demonstrated that photogenerated holes (h+) and superoxide radicals (•O2−) are the main active substances for photocatalytic degradation of TC. Due to the partial reduction of Bi0, the absorption of the catalyst in the near-infrared region was enlarged, which enhanced the photothermal effect of the whole material and further improved the catalyst activity.