The Modification And Application Of Chitosan

Molecules on the natural polymer chitosan has a large number of-NH2 and-OH. They canform stable metal chelates with the metal ions, and they also has some antibacterial properties.Through its modification to enhance metal ion adsorption properties of its antimicrobialproperties, they are more widely used.The first part of this paper is to introduce synthesis of thiacalix [4] arene, then introducesynthesis of epoxytion thiacalix synthesis [4] arene; Finally, the epoxy thiacalix [4] arenecross-linked chitosan, as a final product, is obtained through crosslinking of epoxy thiacalix[4] arene and chitosan . Through access to relevant literature and repeated experiment, theexperimental methods and experimental conditions. Determination of melting point and, FTIR,1H NMR and other analytical tools on the final product of epoxy thia-calix [4] arenecross-linked chitosan and its intermediate products were characterized, the products wereconsistent with the design of routes to achieve the expected purposes.Also, the paper, from the adsorption capacity, effects of medium acidity, adsorptionkinetics, selective adsorption and adsorbent regeneration, study the adsorption of K⁺, Ag⁺,Cd²⁺, Cu²⁺, Ni²⁺, Pb²⁺ adsorption performance. The results show that: the initial concentrationof 0.02mol / L metal ion solution concentrations, S-CTS for K⁺, Ag⁺, Cd²⁺, Cu²⁺, Ni²⁺, Pb²⁺adsorption capacity was 0.432mmol/g, 0.554mmol/g, 1.425mmol/g, 1.612mmol/g, 1.314mmol/g, 1.693mmol/g, compared with chitosan compared to a different degree. Mediumacidity on the adsorption properties has a greater impact, when the pH increases, theadsorption capacity is increased, the optimum pH was 5-6. Adsorbent for several ions have afaster kinetic rate, the fastest one on the Ni²⁺, which is about 3h to achieve balance. In themixed system solution, the adsorbent had a higher Cu²⁺ adsorption capacity and adsorptionselectivity of K⁺, Ag⁺,Ni²⁺ and Pb²⁺ adsorption capacity and adsorption properties of a bitweak,, and the adsorbent has a strong ability to regenerate.The second part, prepared by hydrothermal TiO₂/chitosan nano-composite materials andTiO₂/thiourea chitosan nanocomposites. By FTIR, XRD, SEM, TEM and other analysisproducts were characterized by means of the composite material is a one-dimensional porousmaterial, a thickness of about 10nm, the width is about 80nm. Via development of in vitroantibacterial composite materials on the gram-negative bacteria (E.coli) and Gram-positivebacteria (St.aureus) inhibition, when the concentration of drugs is 2.0mg/ml, TiO₂/chitosannanocomposites and TiO₂/thiourea chitosan nanocomposites St.aureus of E.coli and the sizeof inhibition zone were 14.0cm, 15.0cm, 15.5cm, 16.0cm. TiO₂/chitosan nano-composite materials on the E.coli and St.aureus minimum inhibitory concentration of 0.25mg/ml, TiO₂ /thiourea chitosan nano-composite materials on the E.coli and the minimum inhibitoryconcentration St.aureus To 0.125mg/ml.