Synthesis of Biological Nanocomposite Hydrogels Based on Kappa-Carrageenan/Fe3O4 Nanoparticles for Ammonia Adsorption in Aquatic Ecosystems

With the industrialization of aquatic ecosystems, the concentration of ammonia in surface water and groundwater have been much higher than standards, and large amounts of industrial, municipal and agricultural effluents containing ammonia are released into water sources, producing unhealthy and harmful products. The aim of this study was to synthesis the biological nanocomposite hydrogels based on kappa-carrageenan/Fe3O4 nanoparticles to absorb three samples of agricultural effluent containing ammonia.

Hydrogels are the most suitable bio-sorbents that exist naturally and synthetically. In this study, carrageenan and acrylic acid hydrogels in the form of radical polymerization were prepared in the room by methylene bis-acrylamide as the crosslinking agent and ammonia persulfate as the initiator. Then, a magnetic hydrogel was prepared using divalent and trivalent iron by co-precipitation method.

By adsorbing the ammonia in the two prepared effluent samples, the optimal values ​​for contact time, pH, temperature and adsorbent were 40 minutes, 5, 15 ° C and 40 mg, respectively. The ammonia equilibrium adsorption process by nanomagnetic hydrogels was studied by the Langmuir, Freundlich and Temkin adsorption isotherms, which show that the maximum adsorption belongs to the Langmuir isotherm. Comparison of experimental data with adsorption models showed that these data follow a quasi-quadratic adsorption model. The optimum temperature for the removal of ammonia from both effluents is 15 ° C and the removal capacity in both effluents increases with rising pH from 2 to 10.

According to the results of this study, it can be estimated that the adsorbent studied in this study, which is a nanomagnetic hydrogel of iron oxide, had a significant reduction in the amount of ammonia in the effluents. It can be said that the nanomagnetic hydrogel of iron oxide is an effective adsorbent for the rapid removal of ammonium ions from an aqueous solution.