Enhanced Removal of Cobalt(II) Ions from Aqueous Solution Using Thiourea-Impregnated Gigantochloa albociliata Charcoal Powder

The feasibility of Gigantochloa albociliata (Buluh Madu) charcoal as low-cost adsorbent, effective and locally available material for the removal of cationic of Co(II) ions was investigated. In this study, Gigantochloa albociliata charcoal was impregnated with thiourea as chelating agent. The modification involved impregnation of thiourea into Gigantochloa albociliata charcoal via retort process. The resulting impregnated of Gigantochloa albociliata morphological characteristics for both modified and unmodified were characterize using a Scanning Electron Microscope (SEM). The surface of modified Gigantochloa albociliata charcoal seems to be irregular and uneven, with the present of Thiourea. Energy-dispersive X-ray spectroscopy analysis (EDX) showing the presence of nitrogen and sulphur in modified of Gigantochloa albociliata charcoal indicating the impregnation successfully occurred. The percentage carbon, oxygen, silica exist in modified Gigantochloa albociliata charcoal slightly decrease compared to unmodified. Further analysis of adsorptivity was carried out by soaking the modified charcoal in Co(II) ions aqueous solution and measure using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES). To study the adsorptivity of adsorbent, effect of contact time, initial concentration, and pH was used as parameter. The results show that impregnated charcoal has the highest adsorption of Co(II) ions compared with unmodified of Gigantochloa albociliata charcoal. Further study was carried out by analyse equilibrium data using isotherm and kinetic. Freundlich isotherm shows an excellent fit of experiment data may describe the heterogeneous surface account for multilayer adsorption. For kinetic study, pseudo-second order kinetic model show better fit that involving of chemisorption indicates there is electron sharing or transfer between thiourea (N- and S- groups) and Co(II) ions. From the result obtained, it is describe that impregnation of charcoal with thiourea enhance the intake of Co(II) ions.