GOLD RECOVERY USING CITRUS SINENSIS PEELS AS BIO-ADSORBENT

Abstract

The recovery of gold from electronic waste using locally available and environmentally friendly

materials were investigated. Bio-adsorbent for gold recovery was prepared from Citrus sinensis

peels through mechanical processing and chemical modification. Some ceramic computer

processor units were leached using aqua-regia as lixiviant. Gold was recovered from the solution

using the prepared bio-adsorbent and Sodium Meta Bisulphite (SMB). The recovery efficiency of

the bio-adsorbent was determined and results compared to that of SMB. The adsorption of gold at

different contact times was determined and the concentration of gold in solution was found using

Agilent 4100 Micro Plasma Atomic Emission Spectroscopy (MP-AES). The results obtained

showed that the bio-adsorbent has an adsorption capacity of 98.4% for gold and an adsorption

kinetics correlation coefficient of 0.99989. This is comparable with SMB which has 95.4%.

adsorption capacity and an adsorption kinetics correlation coefficient of 0.98597. The higher

adsorption capacity of the bio-adsorbent is attributed to the binding sites and the chemical

modification which increases the reducing properties of the functional groups present in the

Citrussinensis peels.