Papers by Keyword: Potassium Hydroxide

Abstract: Sn-based lead-free solder alloys have been explored extensively as an alternative to the conventional Sn–Pb solder alloys. While the miniaturization of electronic devices and the growth of appliance area, the corrosion resistance of solder alloys play a crucial element in the reliability of electronic devices in a prolonged period of service. This paper determines the corrosion effect of Sn-Bi solder lead-free solder, particularly immersed in alkaline solution which is potassium hydroxide. Morphological and elemental analyses reveal the formation of oxides on the surface after immersion after using a scanning electron microscope, dispersive energy X-ray and X-ray diffraction. The result of morphology reveals that the Sn matrix in plateau indicated dark contrast while Bi-rich in the lamellar eutectic structure indicated in light contrast appearance. In addition, phase and elemental analyses revealed the formation of mixed corrosion products of SnO, SnO₂ and Bi₂O₃ on the surface after testing. It is hoped that this finding will provide some helpful evidence in clarifying the corrosion progress of lead-free solder alloys. Furthermore, the remaining corrosion potential and current of Sn-Bi in 6 M potassium hydroxide solutions in this research are proposed.

Abstract: This study assessed the effect of potassium hydroxide on geotechnical properties of Biomass fuel ash stabilized lateritic soil. In-situ tests were conducted on the original soil sample for identification and classification purposes. The soil sample was classified as A-2-6. Thereafter, the soil sample was mixed with both Biomass fuel ash and Potassium hydroxide at percentages of 0, 5, 10, 15 and 0, 3, 6, 9 respectively. These were later subjected to various tests such as natural moisture content, specific gravity, sieve analysis, Atterberg limit and compaction .The result showed that the addition of Biomass fuel ash increases the Plastic limit but decreases the plasticity index of the lateritic soil. Similarly, the addition of potassium hydroxide increases the plastic limit while the plasticity index decreases.The addition of Biomass fuel ash increases the optimum moisture content while the maximum dry density decreases. Similarly, the addition of potassium hydroxide increases the optimum moisture content however the maximum dry density decreases. It could be concluded that both Biomass fuel ash and Potassium hydroxide perform satisfactorily as stabilizing agents for stabilizing lateritic soil especially for subgrade and sub base purposes in road construction

Abstract: In this work, single phase Bismuth Ferrite, BiFeO₃ was successfully synthesized by using hydrothermal method assisted with different weight (0.24 g, 0.36 g and 0.48 g) of Chitosan. Potassium hydroxide (KOH) were used as a mineralizer during the synthesis process for the precipitation. The samples were characterized for different properties such as structural and optical properties, and were then compared with previous works. The X-ray diffraction data for all the samples showed that the samples had a single phase belonging to R3c space group with perovskite rhombohedral structure at diffraction angle 32.0° to 32.5° even though the slight presence of secondary phase at diffraction angle 28° was detected. Scanning electron microscope revealed a decrement in particle size as the weight of Chitosan increased indicating effective used of Chitosan in controlling the agglomeration of the particles. All samples BiFeO3 assisted with and without Chitosan showed significant enhancement in energy gap where the obtained results showed a small energy gap values ranging from ~1.22 eV to ~1.88 eV determined from UV-vis absorbance characterization. Therefore, by the addition of Chitosan, the properties of BiFeO₃ such as structural and optical have changed as well as preventing from the particle to agglomerate.

Abstract: The objectives of this study are to investigate the influence of concentration variation of potassium hydroxide (KOH) and to remove a heavy metal in liquid waste of the activated carbon. The raw material of activated carbon was obtained from pineapple crown waste. Pineapple crowns pre-carbonized at 180 ^oC for 1 hour. Chemical activation was carried out using KOH with concentration 2M, 3M, and 4M for 20 hours at 30 ^oC and temperature 60 ^oC for 2 hours. Microwave irradiation was conducted at 630 Watt of output power for 15 minutes. The physical properties of activated carbon were characterized using scanning electron microscopy to determine surface morphology of activated carbon, X-ray diffraction to calculated microstructure (i.e. interlayer spacing and microcrystalline dimension) using Bragg’s and Scherer’s equations, specific surface area was calculated from N₂ adsorption-desorption isotherm using BET equation, Fourier-transform infrared (FTIR) identify the functional groups of activated carbon, and heavy metals absorption was tested using atomic adsorption spectrophotometric. The highest surface area of activated carbon is 300,901 m²/g for activated carbon with concentration 2M corresponding to the highest stack height (L_c) of activated carbon of 10,470 nm. The carbon chain structure shows the functional groups C-H, C≡C, O-H, C-OH, and CH₂ at wavenumbers of 2889,49 cm^-1, 2360,97 cm^-1, 2339,97 cm^-1, and 998,21 cm^-1, respectively.

Abstract: The large quantity of agricultural waste materials that poses disposal challenge to our environment could be converted into useful products such as activated carbon (AC). Palm oil shell based porous AC was prepared by two step process using KOH as the chemical activant. Palm oil shell was carbonized at 800°C for 2 hours and activated using CO₂ at same temperature for 1 hour which yield 23.27% fixed carbon. The AC was characterized by Langmuir surface area, BET surface area and pore volume of 410.7 m²/g, 350 m²/g and 0.2 cm³/g respectively, the FTIR analysis identified the presence of alkanes, carbonyls and hydroxyls as the main functional groups in the AC. Scanning electron microscopy images illustrates the gradual formation of pores from the precursor to the produced AC due to elimination of volatiles and contaminants in the material. However, the AC produced showed basic properties suitable for the removal of hydrophobic organic contaminants in water and wastewater.

Abstract: Adopting the chemical activation method, the high specific surface area activated carbon (AC) was prepared by the solid mixing method using Daqing petroleum cokes as raw materials and KOH as activator. The influence of the ratio of KOH to carbon, activation temperature and activation time on the iodine and methylene blue adsorption properties of the AC were studied. The micro-graphitic structure of the AC was studied by X-ray diffraction (XRD). The BET specific surface area, BJH pore size distribution and pore volume of the AC were determined by N₂ adsorption (at 77K). The experimental results show that the high specific surface area AC can be prepared with the ratio of KOH to carbon of 4, activation temperature of 800°C and activation time of 1h. The specific surface area was as high as 2142 m²/g with the iodine adsorption value of 288mg/g and methylene blue adsorption value of 1266mg/g. The XRD and BJH results also show that amorphous carbon was the dominating form, and the pore size distribution represents micropore structure.

Abstract: Activated carbon (AC) is a kind of artificial carbon materials with highly developed pore structure and high specific surface area. As sound adsorption materials, the AC shows excellent adsorption property, good chemical stability, high mechanical strength and easy-to-regeneration characteristics, which makes it a widely application in the fields of chemical industry, environmental protection, food and pharmaceutical industry, electrode materials, and so on [1-3].

Abstract: The mesophase (iron aluminate, etc.) in steel slag was extracted by potassium hydroxide-sucrose (KOSH) solution method. The effects of partical size of steel slag, temperature and time of extraction on dissolution of mesophase phase were studied. The composition and morphology of the residue were analyzed by XRD and SEM. The results show the mesophase in steel slag powders (the weight was and the fineness was) could be fully dissolved when 4.00 g sample with a fineness about 600m²/kg is used and extraction temperature is kept at 90 ^oC, however, other minerals in the steel slag could be hardly dissolved. The reason might be for that, in alkaline environment which provided by potassium hydroxide, the replacement of ions were took place between the mesophase in steel slag and the organic ligands formed by sugar and potassium hydroxide, and through the adsorption and polarization between ligand and steel slag surface, it will result in the decrease of activation energy of iron aluminate.

Abstract: Activated carbons are prepared from hemp stem with KOH as activating agent under different ratio of KOH to carbon conditions. The BET(Brunauer Emmett and Teller) specific surface area of the hemp stem-based activated carbons first increases and then decreases with the increasing ratio of KOH to carbon. The specific surface area, micropore surface area and volume of the activated carbons reach a maximum of 1589.27m²/g 1420.52m²/g, 89% of the total area, 0.751m³/g at the ratio of 4.5:1. The micropore size distribution shows the activated carbons contain a large number of ultramicropore and supermicropore.

Abstract: This study investigates the activation of waste carbon fiber by microwave heating and potassium hydroxide and the adsorption of aqueous dye RB19 using said modified waste carbon fiber. Heating was performed in a microwave that was set to 900 W from 20 to 60 minutes (M20, M40, and M60). The specific surface areas of the original waste carbon fiber (WCF), M20, M40, and M60were 2 to489 m2/g. M40 had the highest specific surface area and an acceptable yield of 62%. In adsorption experiments at 57°C, the original waste carbon fiber adsorbed only 15 mg of dye/g of fiber. The results reveal that the capacity of adsorption increased when the waste carbon fibers were modified by activation with microwave and potassium hydroxide. Remarkably, M40 was the most suitable absorbent of aqueous dye RB19 and it had the highest capacity of 202 mg/g.