Original Articles
Zulkarnain Chaidir, Rahmiana Z
Abstract
Jengkol shells (Pithecellobium jiringa (jack) prain.) a agricultural waste from typical Indonesian plant has been investigated for its ability to absorb Cr(VI) and Cr(III) heavy metal ions. Effect of pH , concentration , contact time , mass and the speed of stirring on biosorptivity was studied by the method of Batch . The concentration of Cr(VI) and Cr(III) metal ions was measured using Atomic Absorption Spectrophotometer (AAS) . The optimum conditions for metal ions uptake of Cr(VI) occurs at pH 4 , the concentration of 7000 mg / L , contact time of 60 minutes , 0.1 g biosorbent mass and stirring speed 100 rpm . As for Cr(III) metal ions is obtained optimum conditions at pH 5 , the concentration of 1500 mg / L , contact time of 60 minutes , 0.1 g biosorbent mass and stirring speed 100 rpm . Functional groups contained in the jengkol shells analyzed using Fourier Transform Infra Red (FTIR) . Data equilibrium uptake of Cr(VI) and Cr(III) metal ions by the jengkol shells analyzed using two isotherm models , namely Langmuir and Freundlich isotherm models . The absorption of both the metal ions tend to follow the Langmuir isotherm models in which the absorption capacity of metal ions obtained for Cr(VI) and Cr(III) is 24 , 9376 mg / g and 39 , 0625 mg / g . The optimum condition was applied to study the Batang Arau river water in Padang city obtained a capacity of 15 , 065 mg / g with 45 efficiency , 94 % for the uptake of metal ions Cr (total ) .