Study On Synthesis And Adsorption Properties Of Novel Calixarene-chitosan Polymers

In this paper,three new types of Calixarene-Chitosan polymers were prepared from two kinds of materials of Calixarene and Chitosan with good adsorption properties,including three types:Calix[4]arene-Chitosan polymers(C[4]CSP),Calix[6]arene-Chitosan polymers(C[6]CSP),Calix[8]arene-Chitosan polymers(C[8]CSP),and the adsorption abilities of the new polymers toward heavy metal cations and rare earth metal cations were tested.Triflate Ester of Calix[n]arenes(n = 4,6,8)were synthesized based on a new synthetic route,then TEC[n](n= 4,6,8)were further modified by reacting with low molecular weight Chitosan(CS)to get three kinds of new Calix[n]arene-Chitosan polymers(C[n}CSP(n = 4,6,8)through Buchwald-Hartwig cross coupling reaction.The structures of C[n]CSP were characterized by FT-IR,XRD,SEM,Elemental analysis and 13C SSNMR.And the results showed that Chitosan was successfully directly introduced to Calixarene.The substitute degree of C[4]CSP,C[6]CSP and C[8]CSP on Chitosan chain is 17.75%,21.08%and 54.53%respectively.The preparation conditions were optimized by orthogonal test.The results showed that the optimum preparation conditions were listed as following:molar ratio(1:2),catalyst(0.05 equiv),THF:DMSO =1:1.5 and reaction time(5h).Experiment results showed that the solubility of all of the polymers was excellent in chloroform.Through the Two-Liquid-Phase Method of Martell and different spectrophotometry,the adsorption abilities on heavy metal cations(Fe3+,Cd2+,Pb3+ and Hg2+),dichromate anions and rare earth metal cations(La3+,Ce3+ and Eu3+)were performed by C[n]CSP as sorbent material.By overcoming the change of the pH value and the hydrogen bond in the aqueous solution,the adsorption percentage of Hg2+ by C[6]CSP reach 98.96%,the adsorption Capacity of C[4]CSP toward Fe3+ was 0.67 mmol·g-1,and the adsorption capacity of C[n]CSP toward dichromate anions is three to four times higher than that of C[n]and Chitosan.All of the results showed that the adsorption abilities of three new polymers were excellent,and they could be applied as new adsorption materials in future.