Batch experimental studies of Hg(II) ion removal from aqueous solution using seven synthetic polymers

In this work application of seven synthetic polymers as adsorbents for the removal of Hg(II) from aqueous solution was studied. The equilibrium studies are systematically carried out in a batch process, covering various process parameters that include agitation time, adsorbent dosage, and pH of the aqueous solution. Variations of Hg(II) concentration in solution have been studied through measuring the amount of DTZ-Hg(II) complex by a double-beam spectrophotometer. Because of absorbance interference of DTZ-Hg(II) complex with DTZ ligands at 480 nm, which is λmax of the complex, the absorbance peak was checked at 595 nm, which belongs to DTZ ligands. Decreasing of Hg(II) concentration after contacting with the adsorbents expressed the efficiency of these absorbents in extraction of mercury(II) even in solution with high mercury(II) concentrations. It was observed in adsorption and desorption tests that synthetic polymers showed significant pH dependence, which affected the removal efficiency, robustly. Adsorption behavior is found to follow Freundlich and Longmuir isotherms. A regeneration study was also carried out.