Equilibrium and kinetics of Pb2+ adsorption from aqueous solution by dendrimer/titania composites

The presence of lead in wastewater is dangerous to aquatic life even in relatively low concentration. In recent years, adsorption becomes an effective and economical alternative technique for removing heavy metals from aqueous solutions. In the current study, the removal of Pb2+ ions from aqueous solution onto generation 4 polyamidoamine (PAMAM) dendrimers adsorbent was investigated. Batch mode experiments were conducted to study the effects of different variables including pH, contact time, initial lead ions concentration, and adsorbent dose on the removal process. It has been found that a maximum lead adsorption was found at pH 7. The maximum adsorption almost reached after shaking for slightly more than 30 min. The adsorption potential and Pb2+ removal started to decrease after initial Pb2+ concentration of 400 ppm. The experimental data fitted well into the Langmuir isotherm. The kinetic showed that the process of adsorption of Pb2+ on PAMAM dendrimers conforming to second-order kinetics. The current study showed that PAMAM dendrimers is a promising adsorbent for removing lead ions from contaminated aqueous solutions.