Biosorption of Copper Ions by Bacillus cereus M¹₁₆ from Aqueous Solution

Abstract

The severity of heavy metal contamination and its potential adverse health impact on the public has led to tremendous efforts being made to purify water containing toxic metal ions. Biosorption is presented as an alternative to traditional physicochemical means for removing toxic metals from ground water and wastewater. Removal of copper from solution was studied using growing cells and washed cells of Bacillus cereus M ¹ ₁₆. Optimum process conditions for maximum biosorption (73.3%) of Cu (II) ions using growing cells were – volume of medium: 50 ml in a 250 ml Erlenmeyer flask; temperature: 30!'C; pH: 6.0; fermentation time: 24 h; inoculum size (24 h cell growth): 3%; initial metal ion concentration: 75 mg/L. Removal of copper using washed cells of the selected strain was investigated in batch mode and equilibrium was attained within 180 min at 30!'C, pH 3.5 when initial metal ion concentration was 100 mg/L using 8.18 g/L biomass (dry weight) in 50 ml saline in 250 ml Erlenmeyer flask. Both Langmuir and Freundlich isotherms were tested and it was found that the former had a better fit with the data.

Keywords:

• Bacillus cereus
• Copper
• Biosorption
• Adsorption isotherm
• Kinetics