Removal of Lead Ions from Water Using Pellet Generated from Bacillus subtilis Isolated from Gold Mining Site in Niger State

Abstract

This work concentrated on the isolation of lead tolerant strains of bacteria, identification of the isolated strain with the highest lead tolerance capacity using microgen identification kit. Also, the efficacy of the generated pellet (dead cell) in the bioremoval of lead from aqueous solutions was determined. A total of nine bacteria were isolated from soil collected from gold mining site in Kontagora metropolis, Niger State. Of the nine isolates, only Bacillus subtilis (KO1) possess high tolerance capacity for high levels of lead ions. The pellet generated from the Bacillus subtilis (KO1) strain was then used to adsorb lead ions from synthetic ion solutions. The isolate's removal efficiency was enhanced by optimizing several physical conditions (pH, temperature, initial lead concentration and contact time). The best optimized adsorption removal efficiency (>90%) was found at pH 3, temperature 40oC with 100 mg/L of initial concentration of lead after 3 hours of treatment. The use of the pellet generated from eco-friendly Bacillus subtilis (KO1) has great potential and additional benefits in terms of lead removal. Keywords: Bacillus subtilis; lead; adsorption; pellet; optimization