Potential of rice husk silica as a source of L-lysine modified silica for adsorption of Fe(III) ion

Abstract

Iron metal (Fe) is one of the most harmful heavy metals for human health. The maximum content of Fe in drinking water allowed by Ministry of Health of the Republic of Indonesia (2010) is 0.3 mg/L. The objective of this study was to synthesize of silica from rice husk and modified with L-lysine for adsorption of iron. Commonly used method for detection of iron is FAAS which has range of detection at 2.5-10 ppm. Therefore preconcentration is needed. This research developed specific adsorbent for application in Solid Phase Extraction (SPE) using silica gel that come from rice husk. The silica then modified by reacted it with 3-aminopropyltrimethoxysilane and then L-lysine. The purpose of modification is to increase the active group on the silica gel surface, making it more selective in binding to Fe(III) ions. The results showed that conditions for the adsorption of Fe(III) by rice husk silica (SSP) and Llysine modified silica (SLL) was pH 2, adsorbent mass was 10 mg and adsorption time was 30 minutes. The highest adsorption capacity of SSP and SLL were 39.7 mg/g and 46.6 mg/g. It can be concluded that rice husk silica and L-lysine modified silica have good potential as adsorbent of iron.