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1.
《Ceramics International》2022,48(20):29967-29976
This study aims to fabricate a low-cost ceramic microfiltration membrane by mixing kaolin 4.2 wt%, silica 5.8 wt%, starch 20 wt%, graphite 30 wt%, and sodium silicate 40 wt%. The produced paste was molded into a cylinder (1.0 cm high, 5 cm diameter) and dried in an oven at 90°C for 1 h, and then sintered in a furnace at 650 °C for 2 h. The characterization of the produced ceramic membrane was performed by X-ray diffraction analysis, Fourier transformed infra-red spectroscopy, and scanning electron microscopy. Furthermore, the contact angle of the membrane surface was measured, thus demonstrating that the surface is hydrophilic. The fabricated ceramic membrane was investigated for its chemical resistance in strongly acidic and alkaline media. The mass loss of membrane in HCl solution at pH = 2 for 200 h was not more than 0.18%, while it was 2% in alkaline NaOH solution (pH = 12). The fabricated ceramic membrane was combined with an electrolysis process for applying as a new hybrid process for copper ions removal from an aqueous solution. The effects of three operating parameters of electric voltage, initial pH, and initial copper concentration on the performance of copper removal percentage were investigated. To investigate the independent effect of the hybrid electrolysis process versus microfiltration, two experiments with and without an electric field were conducted in 100 min. The copper concentration was decreased from 350 to 160 ppm only by applying the microfiltration method, whereas hybrid electrolysis and microfiltration decreased the copper concentration from 350 to 10 ppm. The regeneration of the composite membrane was evaluated in four consecutive cycles. The percentage of copper ions removal after 4 cycles without washing is about 97%. The proposed process is effective and fast for copper ions removal from the solution, with an excellent yield of 97.4%.  相似文献   

2.
《Ceramics International》2022,48(3):3125-3132
The thermal stability, wear resistance and impact toughness of polycrystalline diamond compact (PDC) are the primary determining variables in determining the performance. The cobalt binder contributes significantly to the PDC's thermal stability and wear resistance. To increase the thermal stability of the PDC, this paper used electrolysis to remove the cobalt binder from the polycrystalline diamond (PCD) layer of the PDC with a diameter of 62 mm. The optimal process parameters for cobalt removal via electrolysis were determined by examining the electrolyte concentration, the electrolytic voltage, and the electrolytic time. The cobalt removal impact was evaluated using a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), an X-ray diffraction (XRD), and thermogravimetric analysis-differential thermal analysis (TG-DTA). In addition, the abrasion ratio of the PDC samples were tested. The experimental results indicated that the optimal electrolysis parameters for cobalt removal were obtained when the concentration of cobalt sulphate was 4 g/100 mL, the electrolysis voltage was 2.5 V, and the electrolysis time was 10 h; in this case, the cobalt removal rate from the PCD layer exceeded 80%, and the cobalt removal depth was 372 μm. TG-DTA analysis revealed that the thermal stability of PDC was significantly enhanced as a result of the initial graphitization temperature of the cobalt removal sample being increased from 1071 °C to 1113 °C, but the abrasion ratio rose by more than 20%. It was discovered that electrolysis may efficiently remove the cobalt binder phase from the PCD layer, therefore improving the thermal stability and wear resistance of PDC.  相似文献   

3.
Using used tire rubber (UTR), carbonaceous adsorbents (CAs) were prepared by chemical treatment of the material with HCl, HNO3 and NaOH aqueous solutions and by heat treatment at 900 °C for 2 h in N2 atmosphere (H900). UTR and the UTR-derived products were first characterized in terms of texture by N2 adsorption at − 196 °C and of oxygen surface groups by FT-IR spectroscopy and pH of the point of zero charge (pHpzc). Then, the products were tested as adsorbents of phenol, p-aminophenol, p-nitrophenol, and p-chlorophenol and of chromium, cadmium, mercury and lead in aqueous solution. The development of porosity is very poor in UTR and in the chemically treated products. H900 is the only CA with a better developed porosity, mainly in the regions of meso and macropores. pHpzc is close to 7.0 for most of the CAs. As an exception to the rule, pHpzc is 8.4 for H900. For this CA, the adsorption of all the adsorptives is greater. Usually, adsorption kinetics are fast. This is so in particular for p-nitrophenol and p-chlorophenol, on the one side, and for mercury and lead, on the other side. Adsorption is much higher for mercury and lead than for the remaining adsorptives.  相似文献   

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