A study in the adsorption of Fe2+ and NO3- on pine needles based hydrogels

Novel supports for use as cation and anion adsorbents were prepared from lignocellulosics using pine needles and their carboxymethylated forms by network/hydrogel formation with acrylamide and N,N-methylene bisacrylamide. The hydrogels thus prepared were further functionalized by partial alkaline hydrolysis with 0.5 N NaOH and were characterized by FTIR, SEM and nitrogen analysis. Adsorption of Fe2+ on these hydrogels was carried as a function of time, temperature, pH and ionic strength. The hydrogel having the maximum adsorption capacity was loaded with Fe2+ at the conditions those afforded maximum uptake and was used as novel anionic adsorbent for NO3. The water uptake capacities and biodegradability of the hydrogels before and after the ion loading was studied to evaluate the possible end-uses of these hydrogels as alternate materials in the removal of ionic species from water. (c) 2007 Elsevier Ltd. All rights reserved.