Evaluation of kinetics and equilibrium studies of biosorption potentials of bamboo stem biomass for removal of Lead (II) and Cadmium (II) ions from aqueous solution

Abstract

The discharged of lead and cadmium above maximum permissible limits into surface water and environment without any pre-treatment methods has caused severe heath challenges to humanity. In other to minimize the reoccurrence, this research aim to ascertain biosorption capacity of bamboo stem biomass to remove lead and cadmium from aqueous solution. Batch experiment and data evaluation under optimum removal conditions (such as pH, contact time, temperature, biosorbent dosage, initial heavy metal concentration) were determined. Maximum optimum removal was observed for both metal ions at pH 5, 90 min contact time, 298K temperature with 50 ppm of initial concentration for 95.92 and 80.98% removal for lead and cadmium. Lead revealed better results at all concentrations for bamboo stem biomass with increase in percentage removal as concentration of heavy metal increases. Kinetics and isotherms models were applied and this shows that kinetic models are described and fitted well with pseudo-second order reaction while adsorption isotherm model supported Freundlich model with high R2 values. Thermodynamically, biosorption of lead and cadmium was exothermic and lead was greater than cadmium in the order of spontaneity and entropy. From these results, it can be concluded that bamboo stem biomass has been shown to be productive in removal of heavy metals from aqueous solution. Key words: Biosorption, bamboo stem biomass, heavy metals, kinetics, isotherms, thermodynamics.