Synthesis Of The Functional Resins And Their Adsorption Properties For Deep-removal Of Aqueous Fluoride

In our country, ground water with high concentration of fluoride is widely distributed in 27 provinces, municipalities or autonomous regions. In arid or semiarid areas of north and northwest China, a large number of people drink water containing high concentrated fluoride which poses a significant health hazard. At the same time, high-concentrated fluoride effluent from rubber, fertilizer, semiconductor factories, glass, ceramics, electroplating industries, mine or pharmaceutical industries has caused serious impact on ecological environment. Therefore, research on available techniques for the removal of fluoride has been a very hot topic in the realm of environmental protection at home and abroad. In this paper, several kinds of resins synthesized by using new methods were used to remove fluoride in the aqueous media. IR-FT, SEM, Pore Structure and XPS were used to characterize the structure and properties of the resins. The mechanism for the removal of fluoride has also been discussed. The object of current study aims at exploring a new way to the deep removal of fluoride.Series of differently functional resins were synthesized by nitration-amination, sulfonation-metal supporting, and nitration-sulfonation-amination-metal supporting, using styrene-divinylbenzene polymer (NDA-1800, XAD-4, NDA-150) as matrix. Amino modified resins and amino modified-metal ion supported resins, which had large adsorption capacities, were chosen by adsorption isotherms to study the structure. The result shows that mesopores were dominant for NDA-1800 and XAD-4 modified resins, while micropores for NDA-150.The adsorption performance of the modified resins was also studied. Adsorption isotherms of the amino modified resins indicated that R-P model fitted better with the experimental data than Langmuir and Freundlich isotherm. The values of thermodynamic parameters confirmed that the fluoride sorption was spontaneous and exothermic. The kinetic curves and obtained adsorption rate followed the pseudo-second-order better and Qe followed NDA-1800-NH2>XAD-4-NH2> NDA-150-NH2. Thomas and Y-N model could be used to predict the breakthrough point in the column adsorption. The breakthrough time of NDA-1800-NH2, XAD-4-NH2 and NDA-150-NH2 were 11h,9h and 5h, respectively, when using 1mg/L as the effluent concentration.Series of compound functional materials (NDA-1800-N-S-Fe,XAD-4-N-S-Fe,NDA-150-N-S-Fe) to remove fluoride were synthesized by supporting metal to the amino modified resins. Static adsorption isotherms fitted Langmuir model better. Thermodynamic parameters showed that the reaction was also spontaneous and exothermic. The date of dynamic experiment also followed the pseudo-second-order The adsorption capacity of the above three resins followed the order: NDA-1800-N-S-Fe