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In this study, nitrogen self-doping layered graphitic biochar (Na-BC900) was prepared by catalytic pyrolysis of lotus leaves at 900

A FLUENT software able to predict and assess the electrooxidation of ammonia from the simulation of ammonia concentration and flow field distribution was developed in this study. The flow field-based models of ammonia removal were simulated and modified through the experimental results. The parameter of reaction constant k is corrected to 0.00195, and the modified model fitted well with experimental values, with the error less than 4%. The electrode depth of 4 cm was assessed to be optimal for ammonia removal based on the comparison of the simulation results on ammonia concentration and flow field distribution. The prediction result applied in the industrial wastewater treatment indicated that complete could be achieved at 0.27 Ah/L, and about 50% of total nitrogen was removed at 0.8 Ah/L. About 7% of chloride ions were converted into inorganic by-products, indicating low biological toxicity and risk on environment. The energy consumption increased with the promotion of removal efficiency of total nitrogen, requiring 5.4 kWh/m3 to remove 50% total nitrogen at 0.8 Ah/L. The results show the practicability and feasibility of this FLUENT software tool on the simulation and prediction of electrooxidation process, which can provide the simulation parameter settings for the subsequent application. PRACTITIONER POINTS: A FLUENT software based on the simulation of ammonia concentration and flow field distribution was able to predict and assess ammonia electrooxidation. A modified model is provided with a rate constant k of 0.00195 and the distinction of 4% with experimental results. The optimal electrode depth was predicted to be 4 cm via the obtained model. Complete ammonia and about 50% of total nitrogen could be at 0.27 Ah/L and 0.8 Ah/L, receptively. About 7% of chloride ions were converted into inorganic by-products in industrial wastewater with high chloride.

A novel W doped BiVO4 with rich oxygen vacancies (OVs) oriented on reduced graphene oxide (rGO) photocatalyst (W-BiVO4-x/rGO) was developed by a simple one-step microwave hydrothermal method for efficient removal of ciprofloxacin (CIP) and chlortetracycline (CTC) under visible light. The synergistic effect of W doping, BiVO4 with OVs, and rGO on the enhancement of photocatalytic activity was clarified from experimental and Density Functional Theory (DFT) calculations results. W doping significantly improved the density of photo-generated charge carriers. The introduction of rGO enlarged the specific surface area, expanded the light absorption range, and promoted the charge transfer of BiVO4. OVs both narrowed the band gap and enhanced the generation of O2−. W doping and OVs both enhanced the interactions between BiVO4 and rGO. The CIP degradation rate constant of W-BiVO4-x/rGO photocatalyst was 1.73, 5.32, 6.43, and 10.70 times higher than those of W-BiVO4/rGO, BiVO4/rGO, W-BiVO4, and BiVO4, respectively. Besides, W-BiVO4-x/rGO photocatalyst prepared by microwave hydrothermal method exhibited higher photocatalytic activity and better combination between materials. This study offers a new strategy to address the problem of antibiotic residues in wastewater.

Comparisons of solar-assisted electrooxidation process (SEOP), electrooxidation (EO), and solar photolysis have been addressed to evaluate the performance of bisphenol A (BPA) removal and mineralization. The results presented the BPA removal efficiency of 100% in SEOP was higher than that of 2.8% and 88% at 90 min in direct photolysis and EO process, respectively, indicating the synergistic effect of EO and solar light in SEOP. The investigation of corresponding active species indicated that ·OH and 1O2 played the predominant role in SEOP. The introduction of solar light in the EO process could promote the generation of ·OH, 1O2, and SO 4 ·- and enhance the degradation performance, explaining the synergistic removal mechanism. The density functional theory (DFT) results pointed out the main active sites of BPA attacked by electrophilic reagent based on the calculation of the energy barrier, Fukui index, and molecular orbitals, etc. Taking into account of the identification of intermediates, the possible degradation pathways of BPA mainly included C-C bond cleavage, ring hydroxylation, and ketonization process. The effects of anode materials, illumination intensity, current density, and electrolyte for the degradation efficiency in SEOP were explored. These results exhibited that the efficient removal of BPA in SEOP was achieved with a relatively lower electricity consumption of 1.21 kWh·(m3·order)-1, which provided new insights into the synergistic mechanism and enhanced removal of contaminants.

To enhance the generation of hydrogen peroxide (H2O2), a modified graphite felt cathode doped with nitrogen and boron was developed and used in peroxi-coagulation system to degrade dimethyl phthalate (DMP). After a simple modification method, the yield of H2O2 on cathode increased from 9.39 to 152.8 mg/L, with current efficiency increased from 1.61 to 70.3%. Complete degradation of DMP and 80% removal of TOC were achieved within 2 h at the optimal condition with pH of 5, cathodic potential of − 0.69 V (vs. SCE), oxygen aeration, and electrode gap of 1 cm. Possible mechanism with synergistic effect of electro-Fenton and electrocoagulation process in the peroxi-coagulation system was revealed via quenching experiments. The prospect of this system in the effluent of landfill leachate and domestic sewage was studied, achieving 50% and 61% of DMP removal in 2 h. This efficient system with simple modified cathode had promising prospects in practical applications.

Inefficient utilization of photo-induced charge carriers and low recyclability are limitations for photocatalyst to get access to the practical application. A novel ternary BiVO4/g-C3N4/NiFe2O4 composite with dual Z-scheme heterojunction was successfully developed and constructed to enhance the separation of photo-induced charge carriers and the absorption range of visible light. The structure, composition, morphology, magnetic, and optical properties of this photocatalyst were investigated comprehensively. The photocatalytic performance, mechanism, and pathway of ofloxacin degradation under visible light were studied. Results indicated that the internal interaction between different semiconductors presented the successful fabrication of ternary composite, and its red shift of adsorption range of visible light contributed to an enhancement of photocatalytic ability. The as-prepared ternary composite exhibited highest photocatalytic removal rate constant for ofloxacin, which was 3.8, 16.3 and 71.2 times as much as that of the pure BiVO4, pure g-C3N4 and pure NiFe2O4, respectively. The five successive recycling experiments exhibited the high photocatalytic stability of the as-prepared catalyst, with simple recovery operation due to its magnetic property. The holes and superoxide radicals dominated the photocatalytic degradation process of pollutants. A dual Z-scheme heterojunction other than conventional heterojunction was responsible for the enhancement on redox capacity and the separation of charge carriers. Different transformation products during ofloxacin photocatalytic degradation were identified and transformation pathway was put forward. This study provides a promising strategy on the application of visible-light-driven photocatalysts in water treatment.

The efficient treatment of leachate concentrate is a key issue in the application of membrane technology to leachate treatment. Here a process coupling electrocoagulation with an electro-Fenton-like process was developed and tested for the treatment of leachate concentrate using a dual-anode system. The effects of pH, electrode gap, electrical charge, and suspended solids on the performance of organics and ammonia removal were evaluated with leachate concentrates from a municipal waste incineration facility. 57% of the organics and 60% of the ammonia were removed at the electrical charge of 7Ah/L, the potential of 7 V, and pH of 7. Electro-oxidation by hypochlorite ions generated in situ, electrocoagulation and electro-Fenton-like reaction via hypochlorite and ferrous ions achieved the removal. Higher levels of suspended solids and a smaller electrode gap both benefitted the removal of organics. Most of the fulvic acid and humic acid-like substances in the concentrate were removed, with the treatment effectiveness following the order coupled process > electro-Fenton-like process > electrocoagulation process. This coupled process shows an alternative potential as a preliminary process in the treatment of leachate concentrates.

The human diploid cell line Medical Research Council -5 (MRC-5) is commonly utilized for vaccine development. Although a rabies vaccine developed in cultured MRC-5 cells exists, the poor susceptibility of MRC-5 cells to the rabies virus (RABV) infection limits the potential yield of this vaccine. The underlying mechanism of MRC-5 cell resistance to RABV infection remains unknown. In this study, we demonstrate that viral infection increased exosomal release from MRC-5 cells, conversely, blocking exosome release promoted RABV infection in MRC-5 cells. Additionally, RABV infection up-regulated microRNA (miR)-423-5p expression in exosomes, resulting in feedback inhibition of RABV replication by abrogating the inhibitory effect of suppressor of cytokine signaling 3 (SOCS3) on type I interferon (IFN) signaling. Furthermore, intercellular delivery of miR-423-5p by exosomes inhibited RABV replication in MRC-5 cells. We also show that RABV infection increased IFN-&beta, production in MRC-5 cells and that blocking the type I IFN receptor promoted RABV infection. In conclusion, MRC-5 cells were protected from RABV infection by the intercellular delivery of exosomal miR-423-5p and the up-regulation of IFN-&beta, These findings reveal novel antiviral mechanisms in MRC-5 cells against RABV infection. miR-423-5p, exosomes, and IFN signaling pathways may therefore be potential targets for improving MRC-5 cell-based rabies vaccine production.