Synthesis of a new water treatment agent and its selective removal of anionic pollutants

A novel water treatment agent, chloromethyl polystyrene resin supported task-specific ionic liquid(PS-CH₂-(CH₂)₁₆Im) was synthesized by a bonding method. Cr(Ⅵ) and methyl orange (MO) were selected as model anionic pollutants. The performance of selective removal of anionic pollutants in water was systematically investigated by both static and dynamic column tests. The results showed that PS-CH₂-(CH₂)₁₆Im had good selective adsorption for anionic pollutants. The adsorption equilibrium could be reached in 30 minutes, with static maximum adsorption capacity of 90.9 and 62.8 mg/g for Cr(Ⅵ) and MO, respectively, and also could effectively remove Cr(Ⅵ) at a concentration as low as 0.004 mg/L. PS-CH₂-(CH₂)₁₆Im was easy to regenerate and recycle at least 5 times without obvious loss in adsorption performance. By measuring the association constant, it was known that the adsorption mechanism of PS-CH₂-(CH₂)₁₆Im on anionic pollutants was ion association.