Papers by Keyword: KCl

Abstract: Microbial fuel cells (MFCs) are considered as an economical and sustainable technology for various applications. This study has designed four single-chamber SCMFCs that composed of graphite plates as electrodes and used wastewater as a substrate for microorganisms. In order to evaluate the performance of SCMFC, the experiments were executed in a batch mode over 18 days at various types of salt bridge. Four salt bridges are used namely (KCl, NaCl, KNO₃, and Cotton Rope). It was found that KCl generated a maximum voltage of 989 mv. The following results were obtained for wastewater investigated parameters: COD = 94%, PO₄ = 88.4%, NO₃ = 88%, TSS = 80%, and Fe = 76%, respectively at 1 M KCl. The experiment was then carried out using different values of KCl (1, 1.5, 2, 3 M). It was found that at a molar concentration of 1.5, 1422 mv of maximum voltage has been generated. Results for wastewater treatment demonstrated that COD of 81%, PO4 of 78.2%, NO3 of 79%, TSS of 80%, and Fe of 84%.

Abstract: To remove the surface damages induced during mechanical polishing (MP) of 4H-SiC, a variety of wet etching recipes and etching conditions were studied. By evaluating the epilayers grown on these etching-treated wafers, it has been found that triangular defects (TRDs) are the main defects originated from the MP-induced damages in these samples. High temperature molten KCl etching at 1100 °C with KOH additive is very effective to remove the damaged surface while keeping a relatively flat surface. Epilayer grown on the KCl+KOH etched wafer showed a TRD density <0.9 cm^-2.

Abstract: High temperature (>1000 °C) chemical etching using molten KCl or molten KCl+KOH as the etchant has been carried out to remove the mechanical-polishing (MP) induced damage layer from 4H-SiC surface. Atomic force microscopy observations have shown that line-shaped surface scratches that have appeared on the as-MPed surface could be completely removed by KCl-only etching or by KCl+KOH etching (KCl:KOH=99:1 in weight) at ~1100 °C. Between the two recipes, KCl+KOH etching has shown a higher etch rate (6~7 times) and is able to remove ~9 μm and ~36 μm-thick damage layer from the Si (0001) and the C(000-1) surface, respectively. Besides, KCl+KOH etching seems to have formed a Si (0001) surface covered with atomic steps while KCl-only etched surface is featured with nanometer-scale pores.

Abstract: The Synergistic Corrosion Inhibition of of Sodium Molybdate and Sodium Silicate for Mild Steel in 5 % Kcl Solution at 25 °C was Investigated Using the Conventional Weight Loss Measurement Method and Potentiodynamic Polarization Method. the Obtained Results Show that Carbon Steel can be more Efficiently Protected by the Mixture of Sodium Molybdate and Sodium Silicate than Single Sodium Molybdate or Single Sodium Silicate in 5 % Kcl Solution at 25 °C. Tough the Concentrations of Single Sodium Molybdate or Single Sodium Silicate Reaches up to 1000mg/L, but their Inhibition Efficiencies are both under 74 %. however, when the Concentration of the Combined Inhibitor of Sodium Molybdate and Sodium Silicate is only 200 Mg/L its Inhibition Efficiency is still above 88 %.

Abstract: The influence of sodium hexametaPhosphate on the corrosion of carbon steel in 0.5 mol•L-1 KCl solution at 25 °C was investigated using weight loss measurements, potentiodynamic polarization curves and Scan electron microscope (SEM). The obtained results show that sodium hexametaPhosphate is an excellent inhibitor and the inhibition efficiencies exceed 87 %. The polarization measurements reveal that sodium hexametaPhosphate is an inhibitor mainly controlled by anodic process.

Abstract: The influences of KCl on the performance of G-Grade oil-well cement are discussed in this article. The macro performances including the rheological property, filter loss of slurry and the thickening time, strength and shrinkage of cement are tested. And the reasons why those influence could happen are explained by analyzing the microscopic structure of the cement. The results show that: KCl takes participation in hydration reaction of cement, KAlSiO3 and Ca4Al2H0.34O6.34Cl1.67 are generated in the reaction that could improve the compressive strength of the cement and reduce the shrinkage of the cement, but there is a limited added amount, less than 12% (BWOW) is the best.

Abstract: When potential was less than 1.2 V, electro-degradation rate was not more than 1.2% on both the films prepared using PEG or not. The film prepared with addition of PEG showed better degradation rates in the whole potential range than the film prepared without using of PEG. The highest degradation rates existed at 1.1 V of applied potential for both of the film electrodes, where degradation rate on film with PEG was 93.6% and the rate was 92.2% on the film without PEG. Methyl orange degradation rates increased with increasing KCl concentration from 0 to 0.7 mol/l, while degradation rates dropped down at even higher potential. Degradation rates increased with prolonged irradiation time for both of the two film electrodes.

Abstract: Porous reaction-bonded Si3N4-SiC composites were fabricated by using potassium chloride(KCl) as pore-forming agent. Green bodies with 20% SiC and 30% KCl in mass were subjected to presinter in Ar atmosphere at 1000~1200 and then reaction-sintered. The results indicated that Si₃N₄-SiC composites which with about 58.5% porosity could be prepared, and the main phase compositions were α-Si3N4 and SiC. After presintered, the porosity of composites had small decrease, but bending strength increased obviously and little amounts of Si₂N₂O had been found. The distribution of pores of porous ceramics was homogeneous and SiC grains were surrounded by Si3N4 grains and fibres. Lots of needle-like α-Si₃N₄, especially in the high porosity ceramics, could be observed.

Abstract: KCl is usually used as the supporting electrolyte in electrochemical deposition of Zinc oxide materials. Besides the role of supporting electrolyte, it can also influence the morphology of the fabricated materials. In this work, ZnO and zinc hydroxide chloride hydrate (Zn5(OH)8Cl2•H2O) mixture with platelet-like morphology were electrochemically deposited directly on ITO-coated glass substrates at 65°C. The electrolyte was 0.1M Zn(NO3)2•6H2O with KCl concentration varied from 0 to 3.2M. It was found that only ZnO thin film was obtained when the concentration of KCl was below 0.02M. Plates structure appeared as the concentration of KCl increased to 0.04M. Plentiful plates were obtained when the concentration of KCl was 0.05M-0.2M. From the X-ray diffraction, it was confirmed that the plate films was the mixture of ZnO and Zn5(OH)8Cl2•H2O. The plates showed perfect single crystal structure confirmed by selected area electron diffraction. Zn and Zn5(OH)8Cl2•H2O were obtained when the concentration of KCl was above 0.8M.

Abstract: The influence of KCl, K2CO3 and K2SO4 on the initial stages of corrosion of 304-type (Fe18Cr10Ni) stainless steel was investigated at 600°C in 5% O2 + 40% H2O. Small amounts of salt (1.35 .mol K+/cm2) were added before exposure. The exposures were carried out in a thermobalance. Exposure time was 24 hours. Reference exposures were carried out in 5% O2 and in 5% O2 + 40% H2O. The oxidized samples were analyzed by SEM/EDX, XRD and IC. KCl and K2CO3 are very corrosive towards 304L, producing thick non-protective scales. Corrosion is initiated by the reaction of the potassium salts with the protective, chromium-rich oxide forming K2CrO4. This depletes the oxide in chromia and converts it into iron-rich non-protective oxide. In contrast, K2SO4 does not accelerate corrosion significantly.