Biosorption of chromium by using Spirulina sp.

Presence of heavy metals in the aquatic system is posing serious problems and chromium has been used in many industries and the removal of chromium ions from waste waters is significant. Biosorption is one of the economic methods that is used for the removal of heavy metals. In the present study, the biomass generated from the dried Spirulina sp. was used for evaluating the biosorption characteristics of chromium ions in aqueous solutions. Batch adsorption experiments were performed on these leaves and it was found that the amount of metal ions adsorbed increased with the increase in the initial metal ion concentration. In this study effect of agitation time, initial metal ion concentration, temperature, pH, and biomass dosage were studied. Maximum metal uptake was observed at pH = 5. Maximum metal uptake (qmax) was 90.91 mg/g .The biosorption followed both Langmuir and Freundlich isotherm models but the Freundlich isotherm model was better than the Langmuir with R2 = 0.997. The adsorption equilibrium was reached in about 1 h. The kinetics of biosorption followed the second-order rate. The biomass could be regenerated using 0.1 M HNO3. FTIR Spectrums of biomasses revealed the presence of hydroxyl, amino, carboxylic and carbonyl groups. The scanning electron micrograph clearly revealed the surface texture and morphology of the biosorbent.