A Novel Microbial Biofilm for Bioremoval of Nickel from Aqueous Media

This study evaluated the efficacy of a microbial biofilm in removing Ni ions in aqueous media. The biofilm was developed incorporating a garden soil fungus with a bacterium isolated from Ni-rich serpentinite soil. The biofilm was characterized using microscopy, scanning electron microscopy, Fourier transform infrared (FTIR) investigations, and Boehm and potentiometric titrations. Ni removal was determined using batch experiments as a function of pH, Ni concentration, and time. The adsorption isotherm assay was conducted with varying Ni concentrations from 25 to 500 mg/L for 4 days. Isotherm and kinetic modeling were applied to the experimental data to understand the mechanisms of Ni removal. The zero point charge at pH 4.5 indicated the pH values greater than 4.5 is favorable for Ni adsorption. Acidic nature of the biofilm was reflected from Boehm titration data showing higher number of acidic groups than basic groups. With the increase in initial Ni concentration, the uptake increased from 3.43 t...