| Chitosan is composed mainly ofβ- ( 1-4 ) -2-amino-2-deoxy-D- glucopyranose andβ- ( 1-4 ) -2- acetamido-2-deoxy-D-glucopyranose repeating units. And the content ofβ- ( 1-4 ) -2-amino-2-deoxy-D- glucopyranose is more than 60%. Chitosan's properties such as non-toxicity, hydrophilic, biodegradability, biocompatible, reproduction, bacteriostasis and polyelectrolicity and possibility for regeneration leads to a number of applications, mostly in biomedicine, pharmacy, food, paper-making, textile industry, water purification and effluent treatment. In acidic solution, chitosan can be protonated and dissolved in acidic medium due to its free amino groups and then many applications of chitosan are restricted. Therefore, physical or chemical modification is needed to increase the sorption properties and prevent chitosan dissolving in acidic solution. Cross-linking can change the crystalline nature of chitosan and enhance the resistance of chitosan against acid, alkali and chemicals and also increase the sorption abilities of chitosan. Reversed-phase suspension cross-linking polymerization is one of the preparation methods of chitosan resins. The preparation, characterization and application of six kinds of chitosan resins will be done in this paper by using reversed-phase suspension cross-linking polymerization.The structure characteristics and application of chitosan resins will be influenced by viscosity average molecular weight and deacetylation degree of chitosan, stirring speed when reacting and pH value of react solution. The optimum condition, viscosity average molecular weight was 5×105, deacetylation degree was 85%, the stirring speed was 350r min-1 and the react solution pH 7.5, was screened to prepare resin of chitosan microspheres (RCM). RCM were faint yellow, compact and porous spheres, had smooth surface, water absorptivity, weakly basic exchange property and pendant aldehyde group in structure, and its size distribution were narrow. FT-IR indicated that RCM structure had–C=N (Schiff's basic) and glucopyranoside did not open loop. XRD showed that the diffraction peak in crystallization area disappeared and amorphous region dimension increased. DSC exhibited that thermal stability of RCM is less than chitosan powder. All of these results were attributed to cross-linking react happened between glutaraldhyde and nitrogen of chitosan and it changed the crystalline nature of chitosan. The application of adsorption cupric from water solution onto RCM was investigated. The thermodynamic data reviewed that adsorption was spontaneous, endothermic and entropy increased process. And the kinetics data disclosure that the second kinetic equation could fit the adsorption process and liquid film distribution was the limited step.The amino (-NH2) and hydroxyl (-OH) group serve as the coordination and reaction sites with metal ions to be chitosan metal complexes. Recently, people pay more attention to chitosan metal complexes because of its unique properties such as bacteriostasis and antitumorigenesis. The preparation of resin of chitosan cerium complex microshperes (RCCM) by using chitosan and ammonium ceric nitrate was studied. RCCM was deep yellow, compact and porous spheres, had smooth surface, water absorptivity, weakly basic exchange property and pendant aldehyde group in structure, and its size distribution were narrow. ICP-AES, FR, XRD and FT-IR showed that cerium stayed in RCCM and the coordination happened between chitosan and cerium. DSC indicated that thermal stability of RCCM is less than chitosan powder, but more than RCM. Cerium element is one of lanthanide series and has hydrolysis capacities of peptide bond and phosphate bond. Therefore, RCCM should have hydrolysis ability except for properties of normal chitosan resins. The results of application RCCM in hydrolyzing sodium p-nitrophenyl phosphate and organophosphorus pesticide, clarifying apple juice and beer zymotic fluid exhibited that RCCM could hydrolyze peptide bond and phosphate bond. On the other hand, the hydrolysis mechanics of protein and organophosphorus pesticide by RCCM were explained.In a few years, a new type of chitosan particles, magnetic chitosan particles, is more welcomed, because they can be easily separated from react medium, are stable in fluidized bed reactor under magnetic field and decrease running cost. The main application of magnetic chitosan particles are affinity chromatography, effluent treatment, immobilized enzyme, target released system and biomolecular immunologic test. The preparation of water-based magnetic fluid was done by using chemical coprecipitation method. And then magnetic resin of chitosan microspheres (MRCM) and magnetic resin of chitosan cerium complex microspheres (MRCCM) were prepared with water-based magnetic fluid and chitosan. MRCM and MRCCM were black, compact and porous spheres, had smooth surface, water absorptivity, weakly basic exchange property, pendant aldehyde group in structure and better relative magnetism, and their size distribution were narrow. The magnetic particles in MRCM and MRCCM were stable when immersing in above pH 2.0 solution. FT-IR showed that the adsorption peak, Fe-O of magnetic iron ore was in MRCM and MRCCM. The application of adsorption methyl orange from water solution onto MRCM and MRCCM were investigated. The thermodynamic data reviewed that adsorption was spontaneous, endothermic and entropy increased process. And the kinetics data disclosure that the second kinetic equation could fit the adsorption process and liquid film distribution was the limited step. Otherwise, the application of adsorption BSA onto MRCM and MRCCM were also studied. The second kinetic equation could fit the MRCM adsorption process and the first kinetic equation could fit the MRCCM adsorption process. Liquid film distribution was the limited step in both MRCM and MRCCM adsorption BSA process. The major sources of polyphenolic compounds in diet are found in fruits and beverages, especially in tea and coffee. It is well known that polyphenolic compounds are effective antioxidants. But polyphenolic compounds are easily oxidized in nature. Then a new type of chitosan covering polyphenolic compounds resins is prepared in order to protect polyphenolic compounds and extend activity. The green tea extract (GTE), which major components are polysaccharide, polypenolic compounds, proteins, amino acids and some trace elements, etc., are produced by the tea product trade. Two kinds of chitosan covering polyphenolic compounds resins, resin of chitosan green tea extract microspheres (RCM-GTE) and resin of chitosan cerium complex green tea extract microspheres (RCCM-GTE) were prepared. RCM-GTE was brown and RCCM-GTE was deep brown, and they were compact and porous spheres, had smooth surface, water absorptivity, weakly basic exchange property and pendant aldehyde group in structure, and their size distributions were narrow. FT-IR showed that the adsorption peak of phenol hydroxy was in RCM-GTE and RCCM-GTE. The effects of RCM-GTE and RCCM-GTE on [DPPH·], superoxide anion free radical, hydroxyl free radical, hydrogen peroxide, ferric reducing force and molybdenum reducing force were better.
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