Chemo-thermal Treatment of Tribulus tresstris to Enhance Its Sequestering Potential for Adsorption of Some Heavy Metals from Aqueous Media: Kinetic and Thermodynamic Study

The plant based renewable biosorbents have extensively been investigated for removing water pollutants. The present study describes the sequestering of metal ions by exploiting a low cost biomaterial derived from Tribulus tresstris as sorbent. The batch equilibrium studies have been carried out both with raw and chemically/thermally treated biomaterial as a function of pH, contact time, shaking speed and shaking time to decide the effectiveness of biosorbent. The sorbent was activated chemically by utilizing 0.1M HCl and 0.1M K2CO3. A close muffle furnace was used for thermal treatment of the sorbent. The adsorption capacity was enhanced to 25% by thermal treatment and 54% by chemical treatment because of increase in pore volume and surface area. The greatest sorption was found for particle size of 200 mu m with a 0.5 g dosage at pH 6 for 20 min at shaking speed 100 rpm. The FT-IR and SEM study was performed to discover the adsorption capacity of various functional groups and their binding mechanism. The adsorption data demonstrates that Langmuir, Freundlich and Dubinin-Radushkevich isotherm models were very much fitted to describe the adsorption behavior.