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Two magnesium alloys with the nominal compositions of Mg−6Gd−3Y (GW63) and Mg−6Gd−3Y−1Ag (GW63−1Ag) were hot extruded and then processed by 6 passes of the simple shear extrusion (SSE) process at 553?K. Both SEM and EBSD studies confirmed the mean grain size reduction of the extruded base GW63 alloy from 10.1 to 2.9?μm by adding 1?wt% Ag. This decrease in the grain size was due to the formation of the Ag-containing precipitates with network-type morphology at the grain boundaries of the extruded GW63−1Ag alloy. Further grain refinement was achieved after SSE through the occurrence of DRX in both Ag-free and Ag-containing alloys. However, the GW63−1Ag alloy showed a higher fraction of DRX grains and HAGBs after SSE processin
This study aims to improve bacterial laccase enzyme activity (LEA) and dehydrogenase activity (DHA) affecting acetylsalicylic acid (ASA) biodegradation using an alternating current (AC). A microbial consortium was inoculated in an electroactive bioreactor supplied with an AC by a function generator under operating conditions of amplitude (AMPL)= 2–10 peak-to-peak voltage (V pp), optical fiber splice tray (OFST)= 0.1 V, and sine wave frequency= 10 Hz. The obtained results revealed that at an applied voltage of 8 V pp and an OFST of 0.1 for 12 h, the maximum bacterial LEA and DHA were 30.6 U/mL and 75.5 micro grTF/cm 2. gr biomass; respectively. Cell viability and permeability were equal to 95.7% and 0.3%; respectively, at the voltage of 8
Low-frequency ultrasonics is a potential technology to reduce the hydrolysis phase period in anaerobic digestion process. In this study, the?influence of combined low frequency ultrasonics and micro-aerobic (MA) pretreatment on sewage sludge solubilization, enzyme activity and anaerobic digestion were assessed. Initially, the effect of ultrasonic density (0.012, 0.014, 0.016, 0.018, 0.1, 0.12 and 0.14 W/mL) and irradiation time (1,3,5,8,9,10 and 12 min) of 20 kHz frequency waves were investigated. Accordingly, the effect of micro-aerobic pretreatment (Air flow rate (AFR) =0.1,0.2, 0.3 and 0.5 VVM) within 20, 30, 40.48 and 60 h were examined. In addition, the effect of combined pretreatment on COD solubilization, lipase enzyme activation, AT
The present study introduced a laboratory-scale, anaerobic treatment system for the removal of oil 11 from synthetic wastewr using a biofilm-electrode reactor (BER). The operating parameters of 12 current intensity, initial concentration, reaction time, and supporting electrolyte were investigated. 13 The results of the present study showed that the optimal conditions were: a current intensity of 15 14 mA, COD concentration of 1500 mg/L, a reaction time of three days, and a supporting electrolyte 15 (NaCl) of 150 mg/L. The highest efficiency for the removal of COD was 86.7% using the 16 introduced method, while it was 65.9% using biological processes. Increased efficiency was 17 attributed to the employment of the proposed bioelectrochemica
Landfill leachate (LL) are well known with low biodegradability and bio-methane potential (BMP) due to recalcitrant compounds and limited potential microorganisms. In turn, pretreatment step and addition co-substrate seem mandatory to improve the biodegradation and enhance the energy output. The present study was developed to assess the electrochemical oxidation (EO) and electrochemical conversion in low current density to improve LL bioavailability in anaerobic co-digestion (LL + Sludge) process. The enhanced biodegradability index: soluble COD (sCOD) and total volatile fatty acid (TVFA) of LL using EO pretreatment process were optimized under operational parameters: current density (10–40 mA/cm2), electrode gap (0.5–2 cm), and
The main objective of this study is to offer an effective electrocatalytic system with high selectivity to nitrogen and low energy consumption using Ni–Fe0@Fe3O4 nanocomposite. The Ni–Fe0@Fe3O4 nanocomposite electrode for electrocatalytic denitrification prepared via an electrodeposition method. Factors effective on nitrate electrocatalytic reduction such as current efficiency, nitrate removal, nitrite and ammonia generation, nitrogen selectivity, and energy consumption were studied using the Ni–Fe0@Fe3O4 nanocomposite electrode. The Ni–Fe0@Fe3O4 nanocomposite was characterized by BET, FE-SEM, EDX, and XRD techniques. The proposed electrocatalytic system reached 90.19% nitrate removal efficiency using 5 mA/cm2 current density with
In the present study, minimization of hazardous bio-sludge production was investigated using a bioelectrochemical system supplied by an alternating current electric field and supplemented with phenol as a cabon source. The experiments were conducted in an air-conditioned bioreactor and at neutral pH value. Moreover, steel wool and carbon cloth were utilized as electrodes in the bioelectrochemical system. The experiments were operated in an air-conditioned bioreactor at 25 ℃ and a neutral pH value with carbon to nitrogen (C/N) ratio of 0.5–6. The results obtained?showed that complete phenol electro-biodegradation occurred at a C/N ratio of?a frequency of 5?Hz, and 0.4 peak-to-peak voltage (Vpp) over 2?h.?Besides, sludge production and sl
Bioelectrochemical systems (BESs) have undergone several modifications to promote enzymes or pathways used to reduce the energy required for microbial metabolism. When an electric current is applied intermittently, changes in dominant bacteria species, population, and growth rates take place. Applying electricity to bioelectrical reactor biofilms can stimulate cells or lead to cell death, and therefore, determination of the applied voltage range that leads to viable and stimulated bacteria is crucial. We investigated apoptosis progression induced by low frequency-low voltage alternating electric current (AC) in a bioelectrical reactor biofilm using indices discussed here. Our results showed that pHzpc for biofilms on the carbon cloth (CC) a
Landfill leachate contains complex, resistant, and diverse compounds that are considered as an environmental health problem. This study aims to investigate the efficacy of integrated homogeneous catalytic ozonation and electrochemical process for improving the biodegradability of landfill. This experimental study was conducted on real landfill leachate on the laboratory scale. The variables were current density (O3/H2O2-42.1 mA/cm2), ozone concentrations (100–400 mg/h), the initial pH (3–9), and the reaction times (1–6 h). The optimum operating condition was obtained at 1.42 mA/m2, 400 mg/h of ozone concentration, initial pH of 3, during 3 h. In the proposed integrated catalytic ozonation-electrochemical process, the chemi
This study aimed to improve the performance of the electrochemical (EC) process for hexavalent chromium [Cr (VI)] removal using a metallic polymer anode. In fact, this anode had been prepared via the immobilized Fe3O4 as the magnetic nanoparticles on microbial cellulose (MC). Moreover, MC/Fe3O4 was modified and conducted by polypyrrole (PPy) and a sandwich panel of stainless steel. The conductive MC/Fe3O4 electrode was characterized by XRD, TGA, FE-SEM, and FTIR. In EC process of the Cr (VI) removal using the composite anode, factors such as chromium concentration, pH value, current density, energy consumption, as well as sludge production were also taken into account. The proposed EC reached 99.87% Cr (VI) removal efficiency using the curr
This research aimed to study the performance of electroactive denitrifying bacteria on biological nitrate reduction using carbon cloth plate and cylindrical stainless steel mesh electrodes in a microbial electrochemical system (MES). The carbon to nitrogen (C/N) ratio, energy consumption, microbial population, nitrate coulomb-reduction rate, and hydrogen production were considered during the experiments. The optimum condition for nitrate removal was obtained at C/N= 2, applied current= 2 mA, and reaction time= 6 h. Nitrate coulomb-reduction rate and hydrogen gas generation were 3.33 mg C–1 and 2.2? 10–4 moles, respectively. The consumption of electricity and power were computed 0.0104–0.096 kWh m–3 and 9.9? 10–5, respectively. The
Hot deformation behavior of the extruded Mg-6Gd-3Y (GW63) and Mg-6Gd-3Y-1Ag (GW63-1Ag) alloys was assessed by shear punch testing (SPT) method in the temperature range of 623 K to 723 K and shear strain rate of 1.6? 10− 2 to 1.3? 10− 1 s− 1. Microstructural examinations showed that Ag addition decreased the initial grain size from 10.1 to 2.9 ?m. According to the hot deformation results, hyperbolic-sine exponents (n-values) of 3.39 and 2.54 were obtained for the Ag-free and Ag-containing alloys, respectively. The corresponding activation energies were found to be 321 and 178 kJ mol− 1 for these alloys. Therefore, the controlling deformation mechanisms were defined as viscous glide of dislocation for the Mg-6Gd-3Y alloy and grain bou