Fe 3 O 4 modified chitosan based co-polymeric magnetic composite hydrogel: Synthesis, characterization and evaluation for the removal of methylene blue from aqueous solutions

• Published in: International journal of biological macromolecules 2023-07, Vol.244, p.125251
• Main Authors: Hingrajiya, Roshni D, Patel, Manish P
• Format: Article
• Language: English
• ISSN: 1879-0003
• DOI: 10.1016/j.ijbiomac.2023.125251

The present research comprises the fabrication of magnetic Fe O incorporated chitosan grafted acrylamide and N-vinylimidazole composite hydrogels (CANFe-1 to CANFe-7) via water mediated free radical polymerization technique using ammonium persulfate/tetramethyl ethylenediamine as initiator. The prepared magnetic composite hydrogel was characterized by FT-IR, TGA, SEM, XRD, and VSM analysis. A swelling study was performed to understand the swelling behavior and found CANFe-4 to be more efficient with maximum swelling hence entire removal studies were performed with CANFe-4. pH analysis was performed to determine pH sensitive adsorptive removal of cationic dye (methylene blue). pH dependent adsorption of methylene blue was dominant at pH = 8 with a maximum adsorption capacity of 860 mg/g. After the adsorptive removal of methylene blue from aqueous media, a composite hydrogel can conveniently be separated from the solution with the use of an external magnet. Adsorption of methylene blue is well explained with the Langmuir adsorption isotherm and Pseudo-Second-Order kinetic model that validates chemisorption. Moreover, it was found that CANFe-4 could be frequently applied for the adsorptive removal of methylene blue for 5 consecutive adsorption-desorption cycles with 92.4 % removal efficiency. Hence, CANFe-4 offers a promising recyclable, sustainable, robust, and efficient adsorbent for wastewater treatment.