Preparation of acid-resistant magnetic adsorbent for effective removal of p-nitrophenol

Bilayer-silane-coated Fe3O4 nanoparticles with inner layer of tetraethoxy silane (TEOS) and outer layer of vinyltriethoxysilane (VTEO) were generated to enhance their acid resistance. These nanoparticles were copolymerized with vinylbenzyl chloride (VBC) using suspension polymerization, and then post-crosslinked. The resulting hypercrosslinked magnetic resin M150 presented specific bimodal property with large specific surface area of 1109 m2/g. It exhibited more excellent adsorption capacity of p-nitrophenol compared to another two magnetic adsorbents Q150 and MIEX®. Moreover, the acid stable property of the magnetite in M150 extended its application at low pH value.