Evaluation of Green microalgae potential for the removal of Lead and Chromium metal Ions through Biosorption Process: Effective Removal of Heavy Metals using Green Microalgae

Abstract

Environmental heavy metal waste is one of the most serious problems today. Decontamination of the heavy metals has long been a problem in the aquatic environment.Several approaches were created for handling polluted wastewater like chemical precipitation, evaporation, electroplating, mixing of ions, membrane systems, and so on. But these methods are associated with some demerits such as high reagent requirement, generation of toxic sludge, difficulties in both to procure and handling. Overcoming to these limitations is possible through biosorption process which utilizes metal binding capacities of biomaterials and micro-organisms, such as bacteria, yeast, algae and fungi from aqueous system. The elimination of heavy metals (Pb+2 and Cr+6) from the single and multi-metallic metal ion solution was performed under batch mode condition. The Biosorption potential of green micro alga S. obliquus biomass evaluates to purpose of pH, biosorbent dosage, contact time, and initial metal ion concentrations. Metal uptake was observed at the 5-7 pH range for Pb+266.9and Cr+6 23.0μg metal mg –1 dry weight from test solutions single ion within 60 min. However, binary and multi metallic system the uptake capacity was observed reduced due to participation among metal ion species for the binding site. Adsorption isotherms studies follows the Freundlish isotherm model which is regulated by weak van der Waalsforces so it is obvious that desorption recovery could be possible. Desorption of was done by using EDTA solution and more than 80 of the adsorbed metal ions was desorbed in the first three consecutive cycles and decrease in both adsorption and desorption values were observed after that. The FTIR study for the algal biomass surface feature community exposed the survival of amino, carboxyl, hydroxyl, and carbonyl groups that are responsible for Pb+2 and Cr+6 biosorption. Therefore this study concluded the biomass of S. Obliquus is a possible layer used to eliminate heavy metals from contaminated marine areas or streams.