Optimization of multimetal adsorption by acid-treated Fabaceae biosorbent: kinetics and equilibrium

The investigation has been carried out on the removal of heavy metals nickel and cobalt using tamarind tree bark (Fabaceae) an easily available and eco-friendly biosorbent from battery industry effluent. The batch biosorption process was conducted and found the process variables using an analytical technique by investigating contact time, dosage, metal ion concentration, and pH. The most significant variables affecting the removal of nickel and cobalt were optimized for getting enhanced percentage removal using face-centered composite design under response surface methodology. The optimum process variables for the removal of nickel and cobalt were found to be: contact time—30.5 min, dosage—1.3 g, initial concentration—5 mg/l, and pH—5.5. The Fabaceae adsorbed 98.21% and 94.68% nickel and cobalt respectively at optimized variables. The equilibrium data were best explained using the Freundlich isotherm. The mechanism of biosorption for both nickel and cobalt on tamarind tree bark was well followed by pseudo-second-order kinetics. The results reported that tamarind tree bark (Fabaceae) is the best suitable biosorbent for the removal of nickel and cobalt from battery industry effluent.