Performance Study Of Exertracting Bromine From Seawater With Bromide Ion Imprinted Resin

Bromide is one of the important chemical raw materials. Bromide and its derivatives have an important significance in national economy and technological development. Seawater as the largest natural element base of bromide, the concentration of bromine in seawater is too low to directly be used by the existed technology. To explore new technologay of exetracting bromine from seawater has a great significance.The resin was prepared of chitosan modified by lanthanum ion and ferric ion, with modified resin is synthesized as precursor polymer. The imprinted resin of bromide ion modified chitosan was prepared in this papper by taking the bromide ion as the imprinting ion. Optimal preparation conditions were as follows:2.0g chitosan/8.0g lanthanum nitrate/1.0mL glutaraldehyde/crosslinking2h of Br-LMCIR;2.0g chitosan/0.3g ferric nitrate/1.0ml glutaraldehyde/crosslinking10h of Br-FMCIR. The equilibrium adsorption method was used to study the adsorption performance and identification ability of the imprinting resin in seawater, and the dynamic adsorption performance of the imprinting resin in the concentrated seawater was investigated. The best adsorption conditions of Br-LMCIR and Br-FMCIR were pH=5, T=30℃and pH=7, T=35℃, respectively. High concentration of Cl-in seawater had some impacts on bromide ion adsorption, but other anions had less effect. Adsorption rate of imprinted resin after repeated use of six times were89.56%and85.86%of the first time, the adsorption capacity were2.2times and1.6times of the blank resin. The imprinted resin displayed higher selective adsorption capacity for Br’and stable repeat performance. The fitting with the equilibrium data showed that the adsorption law conformed to the Langmuir isotherm models. The adsorption kinetics followed the mechanism of the second-order equation for all systems studied. Dynamic adsorption experiment data from concentrated seawater showed that the pH, liquid flow rate and bed height all had significant impacts on adsorption performance of imprinting resin. The BDST model could well describe the relationship between the height of adsorption bed and the penetration time.