Studies on kinetics and adsorption equilibrium of lead and zinc ions from aqueous solutions on Sarkanda grass lignin

Abstract

In this study, the adsorption of Pb2+ and Zn2+ ions from aqueous solutions onto lignin obtained from unmodified Sarkanda grass was analyzed. To ensure optimal process conditions, the retention of lead and zinc ions was tested at different experimental parameters (pH of the initial solution and adsorbent, the dose of adsorbent, the concentration of aqueous solutions and contact time). The experimental results have been interpreted using the classic Langmuir and Freundlich isotherm models, as well as two kinetic models (the Lagergren pseudo-first order and the Ho and McKay pseudo-second order models). Based on the analysis of the experimental data, it has been concluded that unmodified Sarkanda grass lignin can be recommended as an efficient alternative, considering its practical applicability, in the retention of Pb2+and Zn2+ ions from aqueous solutions, both in terms of the amount of adsorbate and pollutant species retained, as well as in terms of adsorption time.