Study of the removal of Zn(II) from aqueous solution using polypyrrole nanocomposite

Zinc is one of the most important pollutants for surface and ground water. Because of its acute Toxicity and non-biodegradability, zinc-containing liquid and solid wastes are considered as hazardous wastes. The aim of this research work is to investigate sorption characteristic of polypyrrole coated on the sawdust (PPy/SD) for the removal of Zn (II) ions from aqueous solutions. The sorption of Zn (II) ions by batch method is carried out. The optimum conditions of sorption were found to be: a PPy/SD dose of 0.5 g in 100 mL of Zn (II), contact time of 14 min, pH and temperature 3 and 40 degrees C respectively. It was found that temperature has a positive effect on the removal efficiency. Three equations, i.e. Morris-Weber, Lagergren and pseudo-second order have been tested to track the kinetics of removal process. The kinetic data indicated that the adsorption process was controlled by pseudo-second-order equation. The Langmuir, Freundlich and D-R are subjected to sorption data to estimate sorption capacity, intensity and energy. The data is fitted with Freundlich. The thermodynamic parameters Delta H, Delta S and Delta G are evaluated. Thermodynamic parameters showed that the adsorption of Zn (II) onto PPy/SD was feasible, spontaneous and endothermic under studied conditions. It can be concluded that PPy/SD has potential to remove Zn (II) ions from aqueous solutions at different concentrations. It was found that increasing the initial concentration causes decreasing in the ion removal. For the desorption experiments, several solvents (alkaline, bases and water) have been used. It was achieved 75% desorption efficiency using NaOH also PPy/SD has been used for the removal of Zn (II) from real waste water (plating wastewater and shows high efficiency in the zinc removal. (C) 2010 Elsevier B.V. All rights reserved.