Removal of lead from aqueous solution by EPS producing bacteria

Abstract

Heavy metal pollution in soil currently becomes a serious environmental issue of worldwide. The present study was carried out to optimize the various environmental conditions for biosorption of lead by investigating as a function of the initial metal concentration (50-250mg L-1), contact time (24-120 hours), and pH (4-8) using EPS producing bacteria (UPI-7) as adsorbent. Biosorption of lead ion from aqueous solution was optimized in a batch system using response surface methodology. The values of R2 (0.9710) for lead ions indicated the validity of the model. The analysis of variance (ANOVA) of the cubic model demonstrates that the model was highly significant. The response surface method indicated that 50 mg L-1 initial lead concentration, pH 6 and a contact time of 72 h were optimal for biosorption of lead in which 61% of the lead was removed from the solution. FTIR spectroscopy spectra analysis indicated that presence of hydroxyl and carboxyl functional groups were involved in lead biosorption process.