Synthesis, characterization and application of triethylenetetramine modified polystyrene resin in removal of mercury, cadmium and lead from aqueous solutions

Polystyrene-triethylenetetramine resin (PS-TETA) was synthesized from chloromethylated polystyrene (PS-Cl) and triethylenetetramine (TETA) and employed as a new adsorbent for heavy metal removal from aqueous solutions. The effects of reaction parameters (reaction solvent, molar ratio of reagents, reaction temperature and reaction time) on the functional group capacity of PS-TETA resin were monitored to specify the best synthesis conditions. The functional group capacity and conversion percentage of functional group of PS-TETA prepared under the optimum condition were 2.13 mmol FG/g and 49.79%, respectively. The structure of PS-TETA was confirmed by elemental analysis and infrared spectra. The optimization of experimental conditions and parameters including pH, contact time, initial metal ion concentration for the removal of heavy metals were investigated. The maximum adsorption capacities of the resin for Hg(II), Cd(II) and Pb(II) evaluated from the Langmuir model were 344.8, 212.8 and 147.1 mg/g, respectively. Desorption studies revealed that Hg(II), Cd(II) and Pb(II) can be easily removed from PS-TETA by altering the pH values of the solution using HCl, which indicate that PS-TETA is a promising adsorbent for heavy metals removal from aqueous medium.