The study describes the sorption of cadmium (II) [Cd (II)]
and nickel (II) [Ni (II)] by dead biomass of Bacillus laterosporus, MTCC 1628. The biosorption conditions
for the removal of Cd (II) and Ni (II) were examined by studying the effect of pH, contact time, biosorbent
dosage and initial metal ion concentration. Shake flask studies yielded adsorption equilibrium in almost
120 min, for both the metals. It was found from Langmuir model that the maximum adsorption capacity
for Cd (II) and Ni (II) ions was 85.47 mg/g and 44.44 mg/g respectively. Kinetic evaluation of the
experimental data showed that the biosorption process followed pseudo-second order kinetics.
Thermodynamic analysis showed that biosorption is an endothermic process with DH8 of 5.45 kJ/mol for
Cd (II) biosorption and 24.33 kJ/mol for Ni (II) biosorption. The surface characteristics of B. laterosporus
biomass before and after metal biosorption were analyzed by using scanning electron microscope (SEM)
with energy dispersive X-ray spectroscopy (EDAX) to study the changes in surface morphology and
elemental constitution of the adsorbent. B. laterosporus exhibited a higher and better potential
biosorbent for the removal of Cd (II) as compared to Ni (II) from aqueous solution