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•Mesoporous-microporous structure created by activation promoted electron transfer.•Activation process decreased N− and O−containing functional groups on the biomass.•Activated ...chestnut shell anode showed higher power output compared to carbon cloth.•The chestnut shell anode had lower internal resistance compared to other biomass.
Microbial fuel cells (MFCs) are promising biotechnologies tool to harvest electricity by decomposing organic matter in waste water, and the anode material is a critical factor in determining the performance of MFCs. In this study, chestnut shell is proposed as a novel anode material with mesoporous and microporous structure prepared via a simple carbonization procedure followed by an activation process. The chemical activation process successfully modified the macroporous structure, created more mesoporous and microporous structure and decreased the O−content and pyridinic/pyrrolic N groups on the biomass anode, which were beneficial for improving charge transfer efficiency between the anode surface and microbial biofilm. The MFC with activated biomass anode achieved a maximum power density (23.6 W m−3) 2.3 times higher than carbon cloth anode (10.4 W m−3). This study introduces a promising and feasible strategy for the fabrication of high performance anodes for MFCs derived from cost-effective, sustainable natural materials.
Poly-zinc silicate (PZSS) is a new type of coagulant with cationic polymer synthesized by polysilicic acid and zinc sulfate. It has been used in several sorts of wastewaters treatment, but not used ...in oily wastewater treatment. In this study, we investigated the coagulation/flocculation of oil and suspended solids in heavy oil wastewater (HOW) by PZSS and anion polyacrylamide (A-PAM). The properties of PZSS cooperated with A-PAM were compared with PAC and PFS in dosages, PAMs amount, settling time, pH value and flocs morphology. The results showed that PZSS was more efficient than PAC and PFS. Under the optimum experimental conditions of coagulation/flocculation (dosage: 100
mg/L, A-PAM dosage: 1.0
mg/L, settling time time: 40
min and pH 6.5–9.5), more than 99% of oil was removed and suspended solid value less than 5
mg/L by using PZSS cooperated with A-PAM, which could satisfy the demands of the pre-treatment process for HOW to be reused in the steam boiler or recycled into the injecting well.
We prepared platelike Mo-doped WO3 films (Mo–WO3) deposited with Sb2S3 for photoelectrocatalytic (PEC) water splitting under visible-light illumination at extremely low input energy (1 mW cm–2). The ...5% Mo–WO3 film exhibited optimal PEC water-splitting performance. Furthermore, Sb2S3/5% Mo–WO3 composite film achieved the highest photocurrent density of 0.42 mA cm–2, nearly 20 times as high as that of 5% Mo–WO3 film. The outstanding PEC water-splitting performance was mainly attributed to synergistic effects of Mo doping and deposited Sb2S3; that is, the enhanced PEC performance not only was assigned to the broadened optical spectrum but also improved electron–hole pairs separation and transfer efficiency. Density functional theory calculation revealed that Mo dopant can modulate the intrinsic electronic structure of WO3 and introduce impurity energy levels resulting from the hybridization between M 3d and O 2p states around the Fermi level, resulting in improved electrical conductivity. Therefore, this work offers new insight for designing metal elements doping into WO3 associated with multifunctional electrode materials for high PEC visible-light-induced water-splitting activity in neutral electrolyte.
► The modified model is suitable for simulating the biological conversion processes. ► Modified model includes simultaneous storage-growth, nitrification–denitrification. ► We have adjusted 11 ...important parameters of model according to our analysis.
The activated sludge model No. 3 (ASM3) was modified to describe the biological reactions in aerobic granular sludge SBR. The simultaneous storage and growth, nitrification and denitrification were all accounted for in modified model. The sensitivities of effluent COD, NH4+–N, and TN toward the stoichiometric and kinetic coefficients were analyzed. A standard set of parameters obtained from a combination of literature data was chosen for the model. The experimental results for the time profile of COD, NH4+–N, and TN in a typical cycle were used to verify the ASM3 model. The verification results show the model established is applicable for simulating the performance of an aerobic granule-based SBR. A comparison of the measured and predicted values of substrate removal for both the modified ASM3 and the original ASM3 was also performed. The verification and comparison results show the modified ASM3 model describes the aerobic granule-based SBR better and more mechanistically.
► N and W co-doped TiO2 were prepared via sol-hydrothermal method. ► The band gap energy of TiO2 has been narrowed due to W/N co-doping. ► W/N–TiO2 electrode sensitized with Fe–chl showed high PEC ...activities.
Sol-hydrothermal method was used to fabricate tungsten (W) and nitrogen (N) co-doped titanium oxide (TiO2) nanoparticles. The nanoparticles were sensitized with a natural dye, sodium–iron–chlorophyllin (Fe–chl). The W and N co-doped TiO2 nanoparticles were analyzed using X-ray diffraction (XRD), filed scanning electron microscopy (FSEM), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). This catalyst was sensitized with different concentrations of Fe–chl to prepare a photoelectrochemical electrode that was characterized by electrochemistry analysis and UV–visible diffuse reflectance spectra. The photoelectrocatalytic (PEC) degradation of methyl orange (MO) under visible light illumination on the obtained electrodes was investigated. The conduction and valence bands of TiO2 were respectively modified with W and N. The 3d orbit of W lowered the conduction band level of TiO2 and the 2p orbit of N shifts the valence band level of TiO2 upward. This condition, along with the excitation of the TiO2 electrode to electron–hole that was induced by porphyrin in Fe–chl under visible illumination, resulted in the high PEC activity of the W/N–TiO2–Fe–chl electrode. The highest degradation (64.3%) and CODCr removal (48.2%) efficiencies of MO on W/N–TiO2–Fe–chl-2mM under visible light illumination for 4h were obtained by applying bias potential +1.5V.
A dynamic membrane bioreactor (DMBR) was developed by substituting dynamic membrane (DM) for the separation membrane in the submerge membrane bioreactor. The formation mechanism and structure of ...dynamic membrane were investigated. Firstly, based on the flux behaviors of dynamic membrane under constant filtration pressure, the formation mechanism of dynamic membrane was assumed in a creative way by dividing the formation process of dynamic membrane into four stages, which was then proved by four classic filtration laws. Furthermore, by the proposed formation mechanism, dynamic membrane from inner to outer was divided into three layers, namely substrate layer, separation layer and fouling layer. Moreover, by combining the theory of hydrokinetic boundary layer with the formation mechanism of dynamic membrane, the methods for calculating the optimum cross-flow velocity on membrane surface and aeration amount for controlling membrane fouling were provided.
► Cr-TiO2NTs were prepared via an electrochemical oxidation method. ► Potassium dichromate was used as the source of Cr dopant. ► Cr-TiO2NTs showed high photoelectrocatalytic activity to remove ...organic pollutant.
Highly ordered Cr-doped TiO2 nanotube arrays (Cr-TiO2NTs) were prepared by the electrochemical oxidation of Ti substrate in glycerol/fluoride electrolyte solution containing potassium dichromate. The Cr-TiO2NTs were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicated that Cr3+ was successfully introduced into TiO2 nanotubes and Cr doping inhibited the crystal phase change of TiO2 from anatase to rutile under high annealing temperature. Compared with pure TiO2NTs, the Cr-doped TiO2NTs exhibited higher photocurrent response, which was influenced by the concentration of Cr(VI) dopant and annealing temperature. The efficient removal of methyl orange (MO) indicated the high photoelectrocatalytic (PEC) activity of Cr-TiO2NTs.
This work investigated the electrocatalytic oxidation of oxalic acid on multiwall carbon nanotubes (MWNTs) modified glassy carbon (GC) electrode. The result indicated that the oxidation of oxalic ...acid was greatly improved at the MWNTs-modified GC (MWNTs/GC) electrode as compared with the bare GC electrode. The effects of the MWNTs suspension amount, pH and scan rate on the electrooxidation response of oxalic acid were studied by voltammetry. The surface concentration and diffusion coefficient (
D
R
) of oxalic acid at the MWNTs/GC electrode were determined by chronocoulometry. This MWNTs/GC electrode presented a wide linear response ranging from 5.0
×
10
−5 to 1.5
×
10
−2
M for oxalic acid. The detection limit (S/N
=
3) was estimated to be 1.20
×
10
−5
M. Based on this MWNTs/GC electrode, the content of oxalic acid in spinach was successfully determined.
ZnFe2O4 nanoparticles （ZFNPs） were developed as catalyst for the degradation of benzotriazole （BTA） by heterogeneous photoelectro- Fenton （PE-Fenton） like process. ZFNPs were prepared by a ...co-precipitation process and then characterized with transmission electron microscopy （TEM）, X-ray fluorescence （XRF）, X-ray diffraction （XRD） and BET surface area. Using such ZFNPs as catalyst, the degradation of BTA was investigated. Due to the high catalytic activity of ZFNPs, PE-Fenton like process showed efficient degradation of BTA. The influencing factors such as pH, dosage of ZFNPs, applied potential and initial concentration of BTA were systematically investigated. Under the optimum conditions, 91.2% of BTA was removed after 180 rain treatment.
The hole-transporting materials of TBDI, NPB and TAPC were used as exciton blocking layer (EBL) in DBP based PHJs for successfully blocking the misdirected electrons. PHJ cell with TBDI showed an ...improvement of 36% in ηPCE relative to the reference cell without any EBL, owing to enhanced optical electric field, stronger prevention of exciton quenching, and a smoother TBDI/DBP surface.
•TBDI, NPB, and TAPC as exciton blocking layers (EBLs) all successfully improved the performance of DBP PHJs.•A highest ηPCE improvement of 36% is obtained by TBDI EBL among the three EBLs.•Optical electric fields for the wavelength of 610nm are significantly enhanced via inserting 10-nm EBLs.•PL spectra indicated stronger prevention of exciton quenching by TBDI.•AFM images suggested smoother donor/acceptor interface with TBDI EBL.
To explore the novel application of the hole-transporting material (HTM) as exciton blocking layer (EBL) in small molecule organic photovoltaic (OPV) cells, we introduce a recently reported HTM, 5,10,15-tribenzyl-5H-diindolo3,2-a:3′,2′-c-carbazole (TBDI), and the other two traditional HTMs, N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (NPB) and 1,1′-bis(di-4-tolylaminophenyl) cyclohexane (TAPC), to serve as EBLs in the tetraphenyldibenzoperiflanthene (DBP) based planar heterojunction cells. Due to the large band gap of these materials, the EBLs successfully block the misdirected electrons. The optimized devices including the EBLs of TBDI, NPB and TAPC achieve power conversion efficiency (ηPCE) of 1.70%, 1.33%, and 1.33%, respectively, whereas the control device without any EBL shows a ηPCE of only 1.25%. The optical simulation indicates that the maximum optical electric fields for the PHJs including 10-nm EBLs at the wavelength of 610nm are significantly enhanced relative to that for the 20-nm DBP based control device. By impedance spectroscopy measurement, the device with TBDI EBL shows lower series resistance and total resistance than the device without TBDI, suggesting fast internal carrier mobility and smaller carrier recombination. The novel HTM TBDI better contributes to the device performance relative to the other two HTMs, stemming from its shallower lowest unoccupied molecule orbits (LUMO) level, stronger prevention of exciton quenching, and a smoother TBDI/DBP surface. These results suggest that TBDI is an excellent candidate as EBL for the DBP based OPVs. The overall ηPCE is further enhanced via optimizing the cathode buffer.
