Study On Purification Of Citrate Desorbing Solution By Ion Exchange Resin

Citrate desulfurization method is one of the most promising among the numerous flue gas desulfurization(FGD) technologies. In this method, first, citrate buffer solution is applied on SO2 absorption, then rich liquid is desorbed, and at last a high concentration of SO2 is formed through collection. In the process of industrial application, as the sulfite oxidation reduction reaction occurs in the process of high temperature desorption, SO42- ion is easy to generate in the solution, and thus lead to the decrease of the absorption efficiency and crystallization of sodium sulfate in the solution after a large number of enrichment. Therefore, deep removal of sulfate radical in solution is required.With the separation of high concentration sulfate ion in the citric acid system by weak basic anion exchange resin as the research object, this thesis studied the exchange resin adsorption, desorption separation and recycling performance under the static condition. By applying the infrared spectrum analysis method, the exchange law of anion in the feed liquid is determined through studying the matrix and functional changes of absorption resin under the condition of static absorption. Besides, the feed flow rate and the impact of column in series on the performance of exchange column are also studied by using dynamic exchange method of breakthrough curve of exchange column.Competitive adsorption will be produced between citrate and sulfate during sulfate purification adsorption. By citric acid protonation of the resin, the adsorption capacity of sulfate exchange can be improved effectively. The desorption time, citric acid concentration, the amount of resin, the impact of p H value can all have impact on the resin adsorption capacity. The capacity of adsorption can reach to the maximum when the citric acid is 1.0 mol?L-1, p H value is 4.5, adsorption of 3 min under the static condition.The concentration of desorption lye and the desorption time will influence the desorption result. When the OH- concentration is 1.5 mol?L-1, sulfate can be completely removed after being desorbed 2 min.Repeated recycling which will cause the gradually decrease of active functional group on the resin will lead to the decrease of the exchange adsorption capacity. Under the static condition, after recycling for ten times, D315 resin adsorption is reduced by 15%. D315 in four resins is acrylic resin, which performance the maximum adsorption capacity under the same weight. Judging from the infrared spectra, its adsorption OHabsorption peak is most obvious before and after the change, which indicates the biggest quantity of exchange ions adsorption.Under dynamic condition, the penetrating time will increase and the exchange resin load rate will improved by reducing the feed flow rate. Series number columns can improve the gross and average penetration capacity, which can further improve the efficiency of exchange column adsorption. The exchange column adsorption can reach the highest efficiency when the flow rate of 10 m L?min-1 in the form of series three columns, its average amount of penetration is 0.5g, which is 100% higher than that of the single column.