Background and Objective: Water interfering anions can cause major problems in the quality of drinking water as well as entering water to the industry. The purpose of this study was to determine the efficacy of granulated metallic-magnetic chitosan nanocomposite for adsorption of interfering anions in aqueous solutions (sulfate, chloride, carbonate and bicarbonate.
Materials& Methods: Synthesis of granulated metallic-magnetic chitosan nanocomposite was conducted based on co-precipitation method. The anions chloride (300-50 mg / L), carbonate (150-50 mg / L), bicarbonate (50- 150 mg / L) and sulfate (50-300 mg / L) were considered. The pH range of the study was between 5- 8 and the remaining time was 0-90 minutes. For the study of the adsorption process, the Langmuir and Freundlich isotherms were considered as pseudo-first and pseudo-second kinetics order at temperatures in the range of 20-45 Celsius.
Results: The results showed that the best removal efficiency of anions was obtained at pH = 5. With an increase in chlorine concentration from 50 mg / L to 300 mg / L, the removal efficiency decreased from 80.06% to 38.22%. This trend has also been observed for other anions in the study, which decreased from 57.82% to 37.69% for sulfate at similar concentrations. In carbonate and bicarbonate, at 50-50 mg / L concentrations, the removal efficiency decreased from 61.15% to 41.17% and 79.66%, respectively, to 49.36%. The percentage of removal of chlorine ion with an amount of adsorbent between 1-5 g / L increased from 62% to 91%. However, increasing the amount of absorbent after 4 g / L did not have a significant difference in removal of chlorine. The same effect was observed for other anions in the study, so that the removal efficiency of carbonate, bicarbonate and sulfate anions in exchange for an increase in the absorbent dose increased from 1 g / L to g / L 5, which was 56% to 93%, 52% to 96% and 53% to 80%. The results of the study showed that the adsorption process follows Langmuir isotherm model and the adsorption of anions is superficial. The absorption model also follows the pseudo-second order kinetic model. In addition, as the temperature rises, the removal efficiency decreases.
Conclusion: The results of the study showed that granulated metallic-magnetic chitosan nanocomposite adsorbent was able to remove the interfering anions from water resources.