A study on the sorption of NO 3 − and F − on the carboxymethylated starch‐based hydrogels loaded with Fe 2+ ions

Using the principle of geochemistry of fluoride, green and cost effective anion adsorbents were developed for the removal of F − from water systems. The scheme was further applied for the removal of NO 3 − also. Carboxymethylated starch functionalized through network formation with acrylamide was used as adsorbent, and the resultant hydrogels were loaded with Fe 2+ ions to generate anchorage for the anions. Sorption of Fe 2+ was studied as a function of different factors such as time, temperature, pH, and ion strength. The network having the highest Fe 2+ uptake was loaded with the Fe 2+ ions under optimum conditions and used for the sorption of F − and NO 3 − . High efficiency has been observed for F − , as even up to 100% uptake has been observed within just 10 minutes. The support shows high selectivity for NO 3 − , which was used as anion reference. Thermodynamics of sorption confirms low order and low energy processes.