Preparation of isoelectric point-switchable polymer brush-grafted mesoporous silica using RAFT polymerization with high performance for Ni(II) adsorption

Abstract

A series of polymer brushes were formed on the surface of mesoporous silica microspheres by copolymerizing 1-vinyl imidazole and acrylic acid through reversible-addition fragmentation chain transfer (RAFT) polymerization, with pI-switchable property and high grafting groups content. The resulting materials (SiO 2 @poly(VI- co -AA)) were then applied for removing Ni(II) from aqueous solution with a fast adsorption rate, and the maximum adsorption capacity was 62.81 mg/g. Significantly, the removal rate of 30 mg/L of Ni(II) could reach up to 99.40%, and the adsorbent also exhibited a good reusability, with the desorption efficiency of over 99%. Furthermore, the adsorption mechanism was supposed to be electrostatic interaction and complexation characterized by Zeta potentials and XPS. It implied that the SiO 2 @poly(VI- co -AA) microspheres could be considered as a potential adsorbent for removing Ni(II) from wastewater, and was expected to expand its application to remove other heavy metals and dyes. • The polymer brush-grafted mesoporous silica was first used for Ni(II) removal. • The SiO 2 @poly(VI-co-AA) microspheres were prepared and characterized. • The adsorbent has good pI-switchable property and high grafting groups content. • The adsorbent shows comparable adsorption capacity and rapid rate. • The adsorbent exhibits a good reusability.