Durian Peel as Biosorbent for Removal of Cadmium Ions from Aqueous Solution

Abstract

The ability of durian peel to remove Cd(II) ions from aqueous solution by biosorption was investigated. The sorption capacities at different solution pH, agitation speed, temperatures, initial cadmium ions concentrations and contact time were evaluated on a batch scale basis. At pH 5 and agitation speed 150 rpm, the cadmium ions removal reached at a maximum value. Increases in cadmium capacity with increasing temperature indicated endothermic nature of the biosorption process. The equilibrium was better described by the Langmuir isotherm model, with a maximum biosorption capacity of 18.55 mg g^-1. The biosorption was relatively quick about 15 min to reach the equilibrium. Biosorption kinetics followed a pseudo-second-order model. Desorption experiments indicate that the desorption efficiency using 0.1 N HCl, HNO₃ and H₂SO₄ aqueous solution were 96.58, 89.90 and 85.92 %, respectively. Fourier Transform Infrared Spectroscopy revealed that carboxyl, hydroxyl, and amide groups on the durian peels' surface involved in the adsorption of the cadmium ions as well as morphological aspects. Biosorption by durian peel has potential to serve as a remover of Cd(II) from wastewater.