Adsorption of Cu (II) and Zn (II) from Water by <i>Jatropha curcas</i> L. as Biosorbent

Abstract The objective of this work was to evaluate the removal of Cu 2+ and Zn 2+ in water by means of the adsorption process using three biosorbents derived from jatropha biomass (bark, endosperm and endosperm + seed coat). The experiments were performed in batch and evaluated the effect of solution pH, adsorbent mass, contact time, different initial concentrations of the metals Cu 2+ and Zn 2+ , and the temperature of the solution during the adsorptive process. By kinetics, the adsorption isotherms and thermodynamics the mechanisms that control the adsorptive process were evaluated. The optimal conditions for the realization of the adsorptive process for both metals were: solution pH of 5.0 and 8 g L -1 of adsorbent mass per volume of solution, with a contact time between adsorbent and adsorbate of 60 min. According to the Langmuir model, the maximum adsorption capacities for the bark, endosperm and endosperm + seed coat of Jatropha were, respectively, for Cu 2+ 11.541, 20.475 and 22.910 mg g -1 , and for Zn 2+ 14.852; 15.888 and 14.674 mg g -1 , with the predominance of chemisorption in monolayer. The three biosorbents derived from the biomass of Jatropha have potential for the remediation of water contaminated with Cu 2+ and Zn 2+ .