Utilization of extracellular polymeric substances (EPS) immobilized in epoxy polymer as double ion exchanger biosorbent for removal of chromium from aqueous solution

Abstract

Extracellular Polymeric Substance (EPS) can be used as a biosorbent and ion exchange bioresin replacing organic resins. It is because EPS contains organic functional groups i.e. cation and anion absorbers. Additionally, epoxy resin also has a sorption capability for chromium ions. In this study, the EPS was immobilized in epoxy polymer to improve usability of the biosorbent. The objective of this research is to study the utilization of EPS immobilized in epoxy polymer as a double ion exchanger biosorbent to remove chromium ions from aqueous solution. The EPS was extracted from activated sludge bacterial by centrifugation at 9000 rpm for 20 minutes at 4°C. The functional group analysis results with Fourier Transform Infra-Red (FT-IR) Spectroscopy showed that the EPS containing chemical bonds such as -CH, -OH, -NH, and -C=O which proved that EPS were exchanging cations and anions. Additionally, the epoxy polymer was prepared by mixing bisphenol A monomers and epichlorohydrin at weight ratio of 1:1. The Immobilized EPS double ion exchange bioresin in epoxy polymers was prepared by mixing 200 mg EPS and 1800 mg epoxy at pH 5, 6 and 7. The analysis results showed that the optimum result gave the chromium ion absorption efficiency of 89.20% at pH 5.