ELECTRODEPOSITION OF ZINC FROM ZINC OXIDE USING UREA AND CHOLINE CHLORIDE MIXTURE: EFFECT OF BMIMHSO_4, TEMPERATURE, VOLTAGE ON CURRENT EFFICIENCY, ENERGY CONSUMPTION, AND SURFACE MORPHOLOGY

摘要

The electrodeposition of zinc from zinc oxide using urea and choline chloride mixture in a molar ratio 2:1 is investigated in different experimental variables, namely, the concentration of added [BMIM]HSO_4, temperature, and applied cell voltage. The additive, [BMIM]HSO_4, was determined to have beneficial effect on the current efficiency, energy consumed in the process and-surface morphology of the deposits. The highest current efficiency (92.6%) and lowest energy consumption (2.92kWh/kg) was obtained for solution with 20mg/mL [BMIM]HSO_4. The morphology showed the formation of absorbed additive layer on the cathode at higher concentration of additives. Experiments were conducted at different temperatures between 343K and 388K and at various applied cell voltages between 2.7V to 3.6V to determine the best experimental conditions. By varying temperature, highest current efficiency (91.3%) and lowest energy consumption (2.69 kWh/kg) was obtained at 373K. The electrodeposition process is enhanced between the applied voltage 3.0-3.3V by achieving lower energy consumption (2.75～3.06kWh/kg) and higher current efficiency (88.4～89.7%). SEM images showed grain size is significantly increased in higher applied voltages. While at higher temperatures, it seemed to generate particle growth as clusters at the outer deposit layer.