Ag (I) modified magnetic poly (1-vinylimidazole/divinylbenzene) as an efficient anion exchange material for methyl orange adsorption

The recent decade has shown an explosion in the development of new nano-materials. Some of the advances have been made in the preparation of magnetic nano-adsorbents. The new materials have made many applications in adsorption, removal and solid phase extraction of target chemicals. One of the most developed nano-adsorbents is magnetic polymer nanoparticles. However, the potential use of the adsorption properties of the new materials remains largely unexplored. Future needs for a clean environment will lead to increasingly higher standards for water pollutants. These challenges require better sorbents that are not commercially available [1]. In this work, a core-shell magnetic poly (1-vinylimidazole/divinylbenzene), PVI/DVB, was prepared. At first, 3-(trimethoxysilyl)propyl methacrylate was grafted to magnetite nanoparticles. Then, the final product was prepared when 1-vinylimidazole and divinylbenzene were polymerized on the surfaces of the silylated magnetite nanoparticles. The prepared magnetic polymer was characterized by Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Imidazole groups on the magnetic material contain electron pair donating sites for adsorption of Ag(I). Therefore, an anion exchange magnetic polymer can be formed. The affecting parameters were investigated and the silver modified PVI/DVB (AgPVI/DVB) was applied for adsorption of methyl orange (MO) as an anionic dye. The experiments showed MO was removed by 95% in pH=8.6 in 5 min adsorption at 30 ºC. Adsorption behavior of MO on AgPVI/DVB adsorbent was correlated with Langmuir, Fraundlich and Temkin isotherm models. The studies revealed that Langmuir model is obeyed more than the other models when MO is adsorbed on AgPVI/DVB.