Biosorption of Pb and Cd using gambir leaf (uncariagambirroxb) with silica gel immobilization technique

Abstract

The Gambir plant (UncariagambirRoxb) is one of the largest commodities in West Sumatera. The Gambir plant contains high cellulose, lignin and tannin compounds which can be utilized as adsorbents to absorb dissolved metals in water. Biosorbents produced from Gambir plants contain tannin compounds that do not have strong bond structures and are so easily degraded, that it is necessary to strengthen the structure by immobilization using silica gel. The biosorbent made consists of BiosorbentWithout Treatment (BWT) and Biosorbent Treatment Silica Gel (BTSG). This research was conducted to determine the ability of leaves of Gambir in absorbing cadmium (Cd). This study was conducted using a batch system. Characteristics of bisorbent obtained for BWT type with moisture content 1.27%, volatile 10.77%, ash content 2.62% and bound carbon content of 85,48%. As for biosorbent type BTSG obtained water content value 5.19%, volatile 21%, ash content 53% and carbon content bound by 24,6%. The optimum conditions obtained are the type of BTSG. Where is the size,concentration of initial waste, dosage and contact time of biosorbent are very influential on the adsorption process. Where the optimum condition are with the biosorbent size of 60 mesh, the concentration of 25 ppm, bisorbent dosage of 5 mg/L and contact time of 30 minutes. The reaction rate runs on the second order and the isotherm adsorption is Freundlich. The recovery rate obtained is 6.39%,energy free Gibbs is -0.068 kJ/mol.