Highly Selective Recovery of Perfluorooctanoic Acid from Semiconductor Wastewater Via Adsorption on PH-Stimulated Poly(Dimethyl Amino)Ethyl Methacrylate Microgels

Abstract

Perfluorooctanoic acid (PFOA) is a high-value chemical which has been widely used in semiconductor industries. Currently, there are a lot of work focusing on the low concentration of PFOA removal due to its potential toxicity, while the recovery of high concentration of PFOA from semiconductor wastewater via adsorption could be more valuable. This work reported a novel pH-stimulated poly(dimethyl amino)ethyl methacrylate (PDMAEMA) microgel for selective PFOA recovery. The results showed that the calculated maximum adsorption capacity for PFOA on PDMAEMA microgel is as high as 3300 mg g^-1 in the presence of 5% (v/v) isopropyl alcohol (IPA). The electrostatic interaction was considered as the main adsorption mechanism combined with hydrophobic interactions. The strong interactions made the adsorption highly selective; therefore, the components in water matrix would not affect the adsorption performance. Meanwhile, due to the pH responsiveness of PDMAEMA microgels, PFOA could be released easily when the solution pH was adjusted to higher values. Finally, the application mode was investigated by incorporating PDMAEMA microgels into a dense membrane, in which the separation of the microgels in water system could be effectively achieved.

Keywords: PFOA recovery, stimulative microgels, membrane adsorption, electrostatic interactions