Study on preparation of defluoridation gel and its performance of fluorine removal from water including fluoride

According to the reaction of Mannich and coordination, a new kind of modified gel with ligand exchange function has been prepared by using polyacrylamide gel (PAMHG), formaldehyde triethylenetetramine (TETA) and Al³⁺. The properties of obtained product for the removal of fluorine from wastewater were reported. Due to the introduction of chelated functional group (TETA) grafted on framework of the polyacrylamide-gel, the properties of capturing Al³⁺ comes out. Moreover, the combination of ligand exchange of Al³⁺ and chelated group have been carried out simultaneously. Thus, the optimal conditions for synthesizing the modified gel and its application to the removal of F^- were investigated further. The results show that the synthetic process of the modified gel is easy to operate, and its performance of removing F^- is excellent. For the water of fluorine concentration about 10mg/L, 90.1% of F^- has been removed from water by adding this gel and the residual concentration of F^- can satisfy China´s national standards for drinking water. In brief, a novel and low-cost method of removing deeply fluorine from groundwater and industrial polluted water is obtained.