Optimization and modeling of Cr (VI) biosorption from aqueous solution on biosorbent - Sarkanda grass lignin

Abstract

The negativ impact induced by the presence of heavy metals in the environment and on the health of living organisms is accentuated by their long-term persistence, as a result of their low solubility and mobility and in close connection with the sorption and complexation processes. In this study, the bioadsorption of Cr (VI) from aqueous solution onto unmodified Sarkanda Grass lignin was analyzed. Cr (VI) retention was tested at different experimental parameters (pH of initial solution and biosorbent, biosorbent dosage, aqueous solution concentration and contact time), in order to obtain optimal experimental conditions. The experimental results have been interpreted using the classic Langmuir and Freundlich isotherms models, as well as two kinetic models (the Lagergren pseudo-first order and the Ho-McKay pseudo-second order models). The experimental data recommend the unmodified Sarkanda Grass lignin as an efficience biosorbent in the retention of chromium ions from aqueous solution, both in terms of the amount of biosorbent and pollutant species retained, as well as in terms of adsorption time.