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•Series of Pd modifying M4/TiO2(M = V, Ce, Mn)catalysts were synthesized.•Pd modification improved the redox ability and surface adsorbed oxygen species.•Pd0.12V4/TiO2 catalyst owned ...the best catalytic performance for dichloromethane.
To improve the catalytic oxidation of dichloromethane, a series of Pd modifying M4/TiO2(M = V, Ce, Mn) catalysts were prepared by impregnation method and characterized by ICP-MS, XRD, BET, O2/NH3-TPD, H2-TPR, XPS and DRIFT. It was found that Pd0.12V4/TiO2 catalyst possessed the best catalytic performance with excellent CO2 selectivity and stability compared to other catalysts. Characterization results illustrated that Pd modification improved the redox ability of catalyst to oxidize DCM to intermediates mainly CO, and the addition of Pd also slightly improved the surface adsorbed oxygen species, which played a great role in further oxidation of CO to CO2. Meanwhile, the V2O5 loading can maximize the acidity of catalyst, which is beneficial for the adsorption of DCM and cleavage of C-Cl bond. The reaction mechanism was concluded that DCM firstly adsorbed on surface acid sites to be further oxidized to CO which then was oxidized to CO2 by the surface adsorbed oxygen species.
Abstract
In order to improve the accuracy of the super-resolution network and reduce the number of model parameters, this paper improves its RCAB module on the basis of RCAN, and builds a ...reconstruction network RSAN that can improve the quality and efficiency of image super-resolution reconstruction. By replacing the original channel attention module with a more efficient and lightweight shuffle attention, it is mainly used to reduce the number of parameters, supplemented by improving the accuracy; and replacing part of the ordinary convolution in RCAN with split convolution is mainly used to improve accuracy, supplemented by reducing feature redundancy and parameters. The experimental results show that RSAN in this paper can not only obtain better subjective visual evaluation and objective quantitative evaluation, but also reduce the number of network model parameters and improve the efficiency of the network to a certain extent.
Activated sludge extracellular polymeric substances (ASEPSs) comprise most dissolved organic matters (DOMs) in the tail water. However, the understanding of the link between the photolysis of ...antibiotic and the photo-reactivity/photo-persistence of ASEPS components is limited. This study first investigated the photochemical behaviors of ASEPS’s components (humic acids (HA), hydrophobic substances (HOS) and hydrophilic substances (HIS)) separated from municipal sludge’s EPS (M-EPS) and nitrification sludge’s EPS (N-EPS) in the photolysis of sulfadiazine (SDZ). The results showed that 60% of SDZ was removed by the M-EPS, but the effect in the separated components was weakened, and only 24% − 39% was degraded. However, 58% of SDZ was cleaned by HOS in N-EPS, which was 23% higher than full N-EPS. M-EPS components had lower steady-state concentrations of triplet intermediates (3EPS*), hydroxyl radicals (·OH) and singlet oxygen (1O2) than M-EPS, but N-EPS components had the highest concentrations (5.96 ×10−15, 8.44 ×10−18, 4.56 ×10−13 M, respectively). The changes of CO, C–O and O–CO groups in HA and HOS potentially correspond to reactive specie's generation. These groups change little in HIS, which may make it have radiation resistance. HCO-3 and NO-3 decreased the indirect photolysis of SDZ, and its by-product N-(2-Pyrimidinyl)1,4-benzenediamine presents high environmental risk.
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•Photosensitizers in ASEPS primarily observed in hydrophobic substances (HOS).•Hydrophilic substances (HIS) in ASEPS are resistant to irradiation and consume ROS.•ASEPS components can produce reactive species for 12 h under illumination.•Variations in ASEPS protein and humus result in different between ·OH and 1O2.•Several by-products of sulfadiazine photolysis exhibit high environmental risk.
Chitosan has been considered attractive in polymer electrolyte membrane fuel cells (PEMFCs) due to its excellent film forming and fuel barrier properties. Reflecting the limitation of its low proton ...conductivity, various materials were used to improve the proton conductivity of chitosan, through combination with inorganic materials like graphene oxide. We present an ideal molecular model for bio-nanocomposites and their mechanism of proton conductivity in PEMFCs. In this study, the diffusion behavior of hydronium ions in chitosan/graphene complex systems at various temperatures, concentrations and pH values were studied systematically using 3 ns long molecular dynamics (MD) simulations with an aim to provide the mechanisms of proton conductivity of chitosan/graphene composite at an atomistic scale. Various amounts of water content (10%, 20%, 30% and 40%), pH values (achieved by adjusting the protonation degree of amino groups of chitosan by 20%, 40%, 60%, 80% and 100%) and numbers of graphene sheets (1, 2, and 3) were considered during MD simulations at 4 temperatures (298 K, 320 K, 340 K and 360 K). Our results indicated that the chitosan system containing 40% water was the most suitable polymer electrolyte membrane and temperature was a key factor affecting diffusion proton. Adding graphene to the chitosan system and adjusting the pH values of chitosan were demonstrated to have a significant effect on improving the proton conductivity of the membrane.
•Molecular model for bio-nanocomposites and their mechanism of proton conductivity in PEMFCs is presented in this work.•Diffusion behavior of hydronium ions in chitosan/graphene complex systems was studied using 3 ns long MD simulations.•Mechanisms of proton conductivity of chitosan/graphene composite were explored at an atomistic scale.•Adding graphene and adjusting pH are efficient ways for improving the proton conductivity of membrane.
Branched polyfluoro sulfonated polyimide (BPFSPI) membranes with different degree of branching and degree of sulfonation are designed and prepared for application in vanadium redox flow battery ...(VRFB). The optimized BPFSPI-10-50 membrane exhibits a similar proton conductivity (2.94 × 10−2 S cm−1) as that of the commercial Nafion 212 membrane (3.20 × 10−2 S cm−1) and a much higher membrane selectivity (3.16 × 105 S min cm−3) than Nafion 212 membrane (0.42 × 105 S min cm−3). Meanwhile, BPFSPI-10-50 membrane is durable in V(V) + H2SO4 solutions for more than 30 d. Both coulomb efficiency (CE) and energy efficiency (EE) of BPFSPI-10-50 membrane are higher than those of Nafion 212 membrane (CE: 94.2–98.9% vs 73.9–94.9%, EE: 68.0–86.9% vs 67.7–77.9%) in VRFB (40–200 mA cm−2) test. Besides, BPFSPI-10-50 membrane displays slower self-discharge rate and excellent discharge capacity retention compared to Nafion 212 membrane. Furthermore, the VRFB with BPFSPI-10-50 membrane shows very stable CE and EE (>98% and 76%) over 200 charge-discharge cycles. Accordingly, the BPFSPI-10-50 membrane with superior cost-performance ratio has an outstanding prospect for application in VRFB.
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•A diamine monomer with polyfluoro structure is successfully synthesized.•Branched polyfluoro sulfonated polyimide (BPFSPI-X-Y) membranes are prepared.•The BPFSPI-10-50 membrane has high membrane selectivity and vanadium ion resistance.•VRFB shows excellent efficiencies and stability by using BPFSPI-10-50 membrane.
In the context of global carbon capping and carbon neutrality, electrochemical methods for converting CO 2 to CO are among the most promising and valuable methods for harvesting greenhouse gas ...pollutants and producing renewable energy. On this basis, nickel-doped layered boehmite (Ni–AlO(OH) 3 ) was grown in situ on reduced graphene oxide (RGO) as a carrier, forming composites with many active sites and good electrical conductivity. The crystal structure, morphology, specific surface area and composition of the samples were characterized. The electrocatalytic carbon dioxide reduction (ECR) performance of these catalysts was evaluated. The results show that the Ni–AlO(OH) 3 @RGO catalyst has high product selectivity, with only carbon monoxide and hydrogen as the gas phase products and no liquid phase products, and the carbon monoxide faradaic efficiency (CO FE) can reach 92.20%, while the CO FE of AlO(OH)@RGO and Ni(OH) 2 @RGO can reach 44.9% and 88.2%, respectively. It was shown that composite catalysts formed by depositing Ni–AlO(OH) 3 hydroxides on reduced graphene oxide had a higher CO 2 RR performance, which was related to the synergistic effect of bimetallic hydroxides and reduced graphene oxide.
In the context of global carbon capping and carbon neutrality, electrochemical methods for converting CO
2
to CO are among the most promising and valuable methods for harvesting greenhouse gas ...pollutants and producing renewable energy. On this basis, nickel-doped layered boehmite (Ni-AlO(OH)
3
) was grown
in situ
on reduced graphene oxide (RGO) as a carrier, forming composites with many active sites and good electrical conductivity. The crystal structure, morphology, specific surface area and composition of the samples were characterized. The electrocatalytic carbon dioxide reduction (ECR) performance of these catalysts was evaluated. The results show that the Ni-AlO(OH)
3
@RGO catalyst has high product selectivity, with only carbon monoxide and hydrogen as the gas phase products and no liquid phase products, and the carbon monoxide faradaic efficiency (CO FE) can reach 92.20%, while the CO FE of AlO(OH)@RGO and Ni(OH)
2
@RGO can reach 44.9% and 88.2%, respectively. It was shown that composite catalysts formed by depositing Ni-AlO(OH)
3
hydroxides on reduced graphene oxide had a higher CO
2
RR performance, which was related to the synergistic effect of bimetallic hydroxides and reduced graphene oxide.
In the context of global carbon capping and carbon neutrality, electrochemical methods for converting CO
2
to CO are among the most promising and valuable methods for harvesting greenhouse gas pollutants and producing renewable energy.
Due to limited land availability in municipal wastewater treatment plants, integrated fixed-film activated sludge (IFAS) technology offers significant advantages in improving nitrogen removal ...performance and treatment capacity. In this study, two systems, IFAS and Anaerobic-Anoxic-Oxic Activated sludge process (AAO), were compared by adjusting parameters such as hydraulic retention time (HRT), nitrifying solution recycle ratio, sludge recycle ratio, and dissolved oxygen (DO). The objective was to investigate pollutant removal capacity and differences in microbial community composition between the two systems. The study showed that, at an HRT of 12 h, the IFAS system exhibited an average increase of 5.76%, 8.85%, and 12.79% in COD, NH4+-N, and TN removal efficiency respectively, compared to the AAO system at an HRT of 16 h. The TP concentration in the IFAS system reached 0.82 mg/L without the use of additives. The IFAS system demonstrated superior effluent results under lower operating conditions of HRT, nitrification solution recycle ratio, and DO. The 16S rDNA analysis revealed higher abundance of denitrification-related associated flora, including Proteobacteria, Bacteroidetes, and Planctomycetota, in the IFAS system compared to the AAO system. Similarities were observed between microorganisms attached to the media and activated sludge in the anaerobic, anoxic, and oxic tanks. q-PCR analysis indicated that the incorporation of filler material in the IFAS system resulted in similar abundance of nitrifying bacteria genes on the biofilm as in the oxic tank. Additionally, denitrifying genes showed higher levels due to aeration scouring and the presence of alternating aerobic-anaerobic environments on the biofilm surface, enhancing nitrogen removal efficiency.
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•The experiments were conducted in a wastewater treatment plant.•The HRT of IFAS system was 4h shorter than that of AAO system.•The nitrification and denitrification capability of IFAS system is stronger than that of AAO system.•The microbial population of nitrifying and denitrifying in IFAS system is more abundant than that in AAO system.•There was a high abundance of genes related to nitrogen removal in the biofilm of IFAS system.
All-inorganic CsPbI2Br, as a promising photovoltaic (PV) material, have attracted extensive research attention in society for its outstanding thermal stability and appropriate trade-offs. ...Carbon-based perovskite solar cells (C-PSCs) without hole transporting layer (HTL) have shown great potential in terms of cost-effectiveness and stability. However, the inevitable defects on the surface of CsPbI2Br films severely hampers the development of high-efficiency CsPbI2Br C-PSCs. Surface engineering has emerged an effective approach to overcome this challenge. Herein, 1-decyl-3-methylimidazolium tetrafluoroborate (DMTT) ionic liquid was introduced between CsPbI2Br and carbon electrode to reduce non-recombination of charges, decrease defect states, minimize the energy-level mismatch, and greatly enhance the device stability. As a result, the HTL-free CsPbI2Br C-PSCs combined with DMTT as an interface modification achieved a higher power conversion efficiency (PCE) of 12.47% than that of the control devices with a PCE of 11.32%. Furthermore, without any encapsulation, the DMTT-optimized C-PSC remained approximately 84% of its initial PCE after over 700 h under room temperature and 25% relative humidity (RH) conditions. Additionally, when exposed to a temperature of 65 °C for over 400 h, the device still retained 74% of the initial PCE, demonstrating its thermal stability.
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