Nitrate Removal by Sorbent Derived from Waste Lignocellulosic Biomass of Lagenaria vulgaris: Kinetics, Equilibrium and Thermodynamics

The equilibrium, sorption kinetics and thermodynamic parameters of nitrate ions sorption using a cationic modified Lagenaria vulgaris shell as a sorbent were studied. The sorption of nitrate ions was carried out from synthetic aqueous solutions in a batch mode. For this purpose, a sorbent based on waste lignocellulosic biomass was utilized. The cationic quaternary ammonium sorbent was obtained by chemical modification of raw Lagenaria vulgaris shell using (3-chloro-2-hydroxypropyl) trimethylammonium chloride reagent. The obtained results of nitrate sorption from synthetic solutions of different concentrations (2-100 mg/L) were examined by non-linear regression analysis of different reaction kinetic and multi-linear diffusion models. To describe the sorption equilibrium in the liquid-solid system, the experimentally obtained data were fitted with typical non-linear models of sorption isotherms (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Sips isotherms). To determine the thermodynamic parameters (Delta G, Delta H and Delta S), nitrate sorption experiments on CMLVS sorbent were performed at different temperatures (20, 40, 60 degrees C), under previously determined optimal conditions. Nitrates desorption and CMLVS sorbent regeneration was also studied. [GRAPHICS] .