Preparation of magnetic double network nanocomposite hydrogel for adsorption of phenol and p-nitrophenol from aqueous solution

Collagen-(AMPS-MAA/AAm)-Fe3O4@SiO2 magnetic double-network nanocomposite hydrogel (DNNH) was synthesized through in-situ free-radical copolymerization under ultrasound-assisted condition. The pure double network hydrogels (PDNH) and their magnetic composite structure were systematically characterized through XRD, FTIR, SEM-EDS, VSM, DTG, and tensile tests. The DNNH exhibits more powerful mechanical attributes (sigma f of 0.33 MPa, epsilon f of 26.5 mm/mm) than PDNH (sigma f of 0.314 MPa, epsilon f of 31 mm/mm). The adsorption process, which is influenced by multiple factors, was examined and the results of the surveys illustrated that the adsorption capacity improved with the Fe3O4 @SiO2 nanoparticles. Adsorption behavior was checked for the adsorption of phenol and 4-nitrophenol and it was found to remove about 77% and 83% of phenol and 4-nitrophenol solutions at pH 7, respectively. The applicability of kinetic and isotherm studies for the adsorption of mentioned pollutions, especially the pseudo-second-order model and Langmuir model were proved (q(m) = 16.52 mg/g for phenol and q(m) = 19.20 mg/g for 4-nitrophenol). Thermodynamic studies proposed that the adsorption of phenol and 4nitrophenol was spontaneous and endothermic. Reusability of the prepared hydrogel in the adsorption-desorption process was simply done for successive 4 times. As a result, the prepared hydrogel is known as a suitable adsorbent for phenol and 4-nitrophenol adsorption from aqueous solutions.