Preperation And Application Of Anionic Tamarind Kernel Polysaccharide

Tamarind kernel polysaccharide(TKP)is a kind neutral polysaccharide which is extracted from the tamarind seed endosperm.TKP aqueous solution has advantages of good acid and alkali tolerance,resistance to high and low temperature and freezing-thaw stability.Anionic tamarind kernel polysaccharide derivitives were prepared and the properties and application were investigated in this paper.Firstly,carboxymethyl tamarind kernel polysaccharide(CMTKP)was prepared by the reaction of TKP and monochloroacetic acid(MCA)and the influence factors affecting reaction were detemined.The maximum degree of substitution(DS)of 0.92 and the corresponding RE of 77%were obtained.The solubility of CMTKP was improved and the transmittance of aqueous solution(2%,w/w)could be up to 97%.Secondly,the carboxymethyl hydroxypropyl tamarind was prepared using MCA and epoxypropane as modifier,the influence factors affecting reaction were studied and the optimum synthesis process was determined.The changes of thermal stability,crystalline region and apparent surface morphology were investigated by TGA(Thermal Gravity Analysis),XRD(X Ray Diffraction)and SEM(Scanning Electron Microscope).The structure was characterized by FT-IR(Fourier Transform Infrared Spectroscopy)and solid-state 13C NMR(13C Nuclear Magnetic Resonance).The application research indicates that the compatibility with surfactants of carboxymethyl hydroxypropyl tamarind was better than that of CMTKP and TKP.Thirdly,crosslinked carboxymethyl tamarind(CCMTKP)with DS 0.42,0.64 and 0.88 were prepared with epichlorohydrin(ECH)as crosslinker and used to adsorb Cu2+,Cd2+and Pb2+from the aqueous solutions.Competitive adsorption showed that in the same ion molar concentration,the adsorption effects for the three metal ions are:Pb2+>Cu2+>Cd2+.The regeneration study indicates that CCMTKP could be used repeatedly without significantly changing their adsorption capacities.Octenyl succinic anhydrate tamarind(OSA-TKP),dodecenyl succinic anhydrate tamarind(DDSA-TKP)and octenyl succinic anhydrate carboxymethyl tamarind(OSA-CMTKP)were prepared and the formula and process conditions were optimized respectively.