Preparation Of Triethylene-tetramine Modified Magnetic Chitosan And Studies On Its Adsorption Properties

Chitosan is a product after chitin deacetylation. It can chelate with many kinds ofmetal ions due to have a lot of amino and carboxyl on its surface. It has a number ofsources, low cost, extensive use and is renewable resources. In addition, chitosan alsohas characteristics of nontoxic, biodegradable, biological compatibility and versatility.Although chitosan has many advantages in terms of adsorption heavy metal ions, itstill has many deficiencies: low adsorption capacity for metal ions, soluble in acidenvironment and not easy to separate after completion of adsorption. In this study, atpresent according to the deficiency of preparing heavy metal ions adsorbent, weprepared modified chitosan, which has high content of coordination atoms, highstability and good magnetic separation performance. Lastly, its adsorption performanceis studied. The ideal adsorption and separation performance were obtained. Thespecific studies are as follows:In the second chapter, first of all, chitosan was modified withtriethylene-tetramine, and then the product was carboxymethylated. Finally, connectthe magnetic ferroferric oxide was introduced to the chitosan molecules. Thetriethylene-tetramine modified magnetic chitosan was successful preparation. Itsstructure and content of each element were characterized by Elemental analysis,Infrared spectrum, solid13CNMR, X-ray diffraction and thermogravimetric analysis.Surface topography was observed by scanning electron microscope.In the third and fourth chapters, firstly, chitosan was cross-linked withepichlorohydrin, and now crosslinking degree of chitosan is due to excessiveepichlorohydrin, and then ferroferric oxide was ultrasonic dispersed into the crosslinked chitosan molecules. Finally, melamine and L-arginine were connected tothe crosslinked chitosan molecules. Melamine and L-arginine modified magneticchitosan were continuous prepared. Intermediate don’t have to be separated. Thepreparation process has been simplified. Its structures were characterized by Infraredspectrum, X-ray diffraction and thermogravimetric analysis. Surface topographieswere observed by scanning electron microscope.In the fifith chapters, magnetic chitosan microspheres were prepared by using themethod of reverse crosslinking, and then it was modified by chloroacetic acid. Finally,magnetic carboxymethyl chitosan was successful prepared. Its structures werecharacterized by Infrared spectrum, X-ray diffraction and thermogravimetric analysis.Surface topographies were observed by scanning electron microscope.Surveyed the adsorption property of above products for Cu2+and Pb2+viaadsorption tests and the adsorption conditions were optimized. Adsorption kinetics andthermodynamics were researched. The dynamics mechanism of adsorption process andadsorption isotherm were discussed, and the rate determining step was analyzed.