Synergistic effect of electrostatic adsorption and ion exchange for efficient removal of nitrate

A novel nitrate adsorption material of quaternized chitosan-zeolite/Fe3+/Mg2+-glutaraldehyde (QZG) beads were prepared for efficient removal of nitrate from aqueous solutions. Modification of chitosan by grafting glycidyl trimethyl ammonium chloride (GTMAC) onto the amino group. The coprecipitation method is used to combine the hydroxide and quaternary ammonium salt modified chitosan to provide more specific active sites and improve the adsorption characteristics of the material. SEM, FTIR, XPS, TGA have been evaluated the physicochemical properties of the material that Indicated that functionalized QZG is favorably synthesized. QZG exhibited exceptional nitrate adsorption capacity (62.23 mg g(-1)) and has fast adsorption and desorption ability that can reach equilibrium with 15 min. Here, 100% regeneration was achieved with desorption of 0.02 mol L-1 NaCl. After six cycles of regeneration, the adsorption capacity was maintained at approximately 96%. The average diameter of QZG was 1-2 mm, which is convenient for recycling. Furthermore, the pseudo-second-order and Langmuir isotherm models fit the experimental data more reasonably, suggesting the occurrence of the physical and chemical adsorption process. These results suggest that QZG adsorbent can be applied to nitrate-containing wastewater in nature.