Study Of The Adsorption And Desorption Behavior Of Amino Group Functionalized Materials

Uranium resource is abundant in the seawater, where the total amount of theuranium reserve is about4.5billion tons which is about one thousand times of that inthe terrestrial mineral reserve. Therefore, the uranium resorce in the seawater is animportant potential reserve for the ongoing nuclear fuel demands. However, there aretwo main obstacles to extraction uranium from seawater economically: the lowconcentration of3.3ppb and the presence of other compatative ions, such as Na+, Ca2+,Mg2+, V5+, Ni2+, Fe3+, Cu2+, Pb2+, etc. The adsorption and desorption behavior of uranylion on the amino group functionalized polymeric materials is investigated in this paper.Amino-type adsorbents (ATAs) were prepared by radiation-induced graftpolymerization (RIGP) of4-hydroxybutyl acrylate glycidyl ether (HB) onto apolyethylene-coated polypropylene (PE/PP) core-shell non-woven fabric, and thenmodified with amines, including ethylenediamine (EDA), diethylenetriamine (DETA),triethylenetetramine (TETA) and diethylamine (DEA).The adsorption behavior of uranyl ions onto the ATAs was studied in batchexperiments, where the effect of the contact time, the initial concentration of the ions,the pH value, the salinity and the temperature were investigated along with theadsorption kinetics and the adsorption isotherms patterns. The UO22+was eluted byhydrochloric acid.The adsorption rate of ATA-DETA was highest. The adsorption rate of ATAs wereinvestigated and the results showed an order of: ATA-DETA＞ATA-DEA＞ATA-TETA＞ATA-EDA. The ATAs have good efficiency in adsorbing uranyl ions, where the bestsaturation adsorption capacity was as high as64.26mg/g for ATA-DETA. Thedependent factor of ATA-DETA was quite abnormal where the quickest behavior wasobtained at25oC as compared with5oC,15oC and35oC. The kinetic experimental dataproperly followed the pseudo second-order kinetic model, and the adsorption isothermscorrelated well with the Langmuir model. The selectivity of amino groups within themixed ion solution was investigated and the results showed an order of: UO22+≈Fe3+> Zn2+> VO3-> Co2+> Ni2+.The detailed adsorption and elution behavior of UO22+on ATAs were examined bycolumn method. UO22+density of the resulting ATA-DETA adsorbents was41mg/g insimulated seawater. The breakthrough curve of adsorption was observed with a flowrate of100h-1space velocity by pumping4ppm UO22+solution into the column. Thetotal consecutive adsorption capacity of UO22+was125.8mg/g. The intermittentadsorption curve was observed with a flow rate of100h-1space velocity by pumping4.5ppm UO22+solution into the column, the total adsorption capacity of UO22+was202.7mg/g.After adsorption, UO22+was eluted by hydrochloric acid. The adsorbent volumes inadsorption and elution were maintained a certain volume. The equilibrium absorptioncapacity lost about28%after an adsorption-stripping cycle.