Remediation of tributyltin contaminated seawater by adsorption using nFe3 O4 , activated carbon and nFe3 O4 /activated carbon composite material

Abstract

The remediation of tributyltin (TBT) by adsorption onto nFe3O4, activated carbon and nFe3O4/ activated carbon composite material as a function of adsorbent dose, contact time, pH, stirring speed, initial TBT concentration and temperature was studied. The effect of temperature on kinetics and equilibrium of TBT sorption on the precursors and the composite was thoroughly examined. The adsorption kinetics is well fitted using a pseudo-second-order kinetic model, and the adsorption isotherm data of nFe3O4, activated carbon could be described by the Freundlich isotherm model whereas nFe3O4/activated carbon composite could be described by the Freundlich and Dubinin–Radushkevich isotherm models. Thermodynamic parameters (i.e. change in the free energy (ΔG°), the enthalpy (ΔH°) and the entropy (ΔS°)) were also evaluated. The overall adsorption process was endothermic and spontaneous in nature. The results obtained also showed that 99.9, 99.7 and 80.1 % TBT were removed from contaminated natural seawater by nFe3O4/activated carbon composite, activated carbon and nFe3O4, respectively.