Research On The Adsorption Of Bromine From Desalinated Seawater By Resins D201

Bromine is one of the important chemical materials and has wide application in the national economy.However it is very shortage in our country.The concentration of bromine,an output's by-product in desalinated seawater,is almost twice than that in the natural seawater.Therefore,to reasonably and availably distill bromine resource from thick sea will reduce seawater desalination cost and the pollution of oceanic environment,and also contribute significantly and realistically to rapid development of seawater desalination industry,oceanic chemical engineering industry and so on.In this thesis,the adsorption kinetics and thermodynamic behavior of bromine from desalinated seawater were studied using D201 macroporous strongly basic styrene type anion exchange resins.Based on the anterior research,the characteristics of adsorption and desorption in distilling bromine by D201 resins from desalinated seawater were investigated and mathematical model of the operation process in column was also established,which could provide theoretical dependence to some extent for the comprehensive utility in the extraction of bromine from desalinated seawater using resins and its further industrialization.The thermodynamic behavior of bromine adsorption from desalinated seawater with resins D201 was researched.The adsorption isotherm data were measured at different temperature and the thermodynamic function change values(⊿G,⊿H and⊿S) were also calculated.The results indicated that the maximal adsorptive capacity of bromine of wet D201 resins was 0.104g/ml and the experimental data were well fitted with Henry adsorption equation. Gibbis free energy change⊿G was less than zero,which mean the adsorption process was spontaneous.The enthalpy change⊿H in the bromine adsorption process was positive,indicating the process was endothermic.The entropy change⊿S＞0,indicating that the adsorption was an entropic increasing process.Resins D201 was applied to study the adsorption kinetics of bromine from desalinated seawater.The influences on the adsorption process including stirring speed,granularities of resin and temperature were investigated. Moving Boundary Model was used to describe the kinetics of adsorption process.The results show that the dominant procedure is ion diffusion through particles;stirring speed and granularities of resin have little influence on the velocity of adsorption;and the adsorption rate increases with the increase of temperature.The apparent rate constant and activation energy were finally calculated.The effect of flow rate and the temperature on bromine adsorption by D201 resins were respectively inspected in laboratory-scale fixed bed.The adsorption capacity of the resins was measured and the performance of desorption of resins was also investigated.The results show that resins D201 have excellent ability of bromine adsorption,the loaded resins can desorb easily with hydrochloric acid,and the desorption property is quite excellent.