An Environmentally Friendly Super-Adsorbent Nanocomposite Based on Poly (N- Vinylpyrrolidone -Co- Maleic Anhydride) and Its Application for Congo Red Dye Removal from Aqueous Solutions

Poly (N- vinylpyrrolidone -co- maleic anhydride) @ eggshell @ Fe3O4 (PNVPMA@ES@Fe3O4) eco-friendly nanocomposite was synthesized by a two-step method. In the first step, the PNVPMA copolymer was synthesized via radical polymerization method. In the second step, the PNVPMA@ES@Fe3O4 nanocomposite was synthesized through an in-situ co-precipitation technique. The PNVPMA@ES@Fe3O4 nanocomposite was used as high performance eco-friendly adsorbent to remove Congo red (CR) dye from aqueous solutions at various conditions, such as pH effect, contact time, adsorbent dosage and dye concentration. Results showed that the percentage removal of CR by synthesized magnetic nanocomposite was more than 95% at pH=6 and contact time 30 min. The results showed that the interactions between CR and the PNVPMA@ES@Fe3O4 nanocomposite were in agreement with the Langmuir isotherm and pseudo second order kinetic model. Also, thermodynamic model showed that the CR adsorption on the synthesized nanocomposite was spontaneous.