Kinetics and equilibrium models for the sorption of tributyltin to nZnO, activated carbon and nZnO/activated carbon composite in artificial seawater

Abstract

The removal of tributyltin (TBT) from artificial seawater using nZnO, activated carbon and nZnO /activated carbon composite was systematically studied. The equilibrium and kinetics of adsorption were investi- gated in a batch adsorption system. Equilibrium adsorption data were analyzed using Langmuir, Freund- lich, Temkin and Dubinin–Radushkevich (D–R) isotherm models. Pseudo first- and second-order, Elovich, fractional power and intraparticle diffusion models were applied to test the kinetic data. Thermodynamic parameters such as DG°, DS° and DH° were also calculated to understand the mechanisms of adsorption. Optimal conditions for the adsorption of TBT from artificial seawater were then applied to TBT removal from natural seawater. A higher removal efficiency of TBT (>99%) was obtained for the nZnO/activated carbon composite material and for activated carbon but not for nZnO.