| This dissertation is supported by the Specialized Research Fund for the Doctoral Program of Higher Education(No.20060225008).In this research we converted cellulose by chemical modification into some materials with high selective adsorbability and good stability.Kidney illness can cause substantial savings of endogenous chemical toxins such as urea nitrogen,uric acid, creatinine and bilirubin,thereby increasing the patient's condition to trigger a variety of complications.The oxycellulose can eliminate these toxins from bodies by chemical adsorption that their aldehyde groups can react with amino groups of urea nitrogen to form imines.Amino groups with lone electron pairs on their nitrogen atoms can complex with most heavy metal ions with empty electronic orbits in their valences shell,so we attached amines to oxycellulose to develop a new polyamine-modified oxycellulose in which small molecule toxins like urea nitrogen could be adsorbed onto aldehyde group and heavy metal ions could be adsorbed onto poly amino group at the same time.We prepared dual functional adsorbents YXA2.3 and YXA3.4 by reactions of diethylene triamine(A2.3) and triethylene tetraamine(A3.4) with YX-Cl as a product from the chlorination of the hydroxy at C6 of YX which was synthesized by oxidating C2,C3 of oral microcrystalline cellulose to aldehyde groups.Meanwhile,the influence factors on the reaction process were investigated.The supermolecular structures and chemical structures of polyamine-modified oxycellulose were characterized by FTIR,elemental analysis and XPS.Their adsorption properties were studied.The results indicated that the yields activating and oxidating microcrystalline cellulose were in the range of 77.5%～82.5%,81%～85%respectively,the aldehyde content in oxycellulose was 97.61%.When oxycellulose was chlorinated in 20mL DMF for 2hs,the yield was about 95%.The appropriate conditions of polyaminating reaction was that oxycellulose chloride in 200mL DMSO was heated to 100℃with stirring,then was dropwised 10mL A2.3 and A3.4 separately,remaining the temperature for 12h,after pH was justed to 4-5,the products were obtained in 46%yield.Compared with theoretical values 49.0%C,7.8%H,17.1%N the elemental analysis results of YXA2.3 that was 45.1%C,4.7%H and 11.1%N showed that oxycellulose chloride were aminated only partially in about 45%yield because of their huge molecular volume.Photoelectron spectroscopy analysis demonstrated that there were four different bond species such as C-C,C-O and C-N,and C = O in products,which shows that the expected modified structure have been received.The infrared spectra also confirmed the results.The adsorption experiments of diethylene triamine-modified oxycellulose showed that:(1) The static adsorbing capacities of 0.5g adsorbent for urea(6g/L),uric acid(1g/L) and creatinine(0.1g/L), were 122.0mg/g,19.8mg/g,3.04mg/g respectively at 37℃and pH7 in 5h.when three adsorption equilibriums were reached after 8h the corresponding adsorption capacities were 123.9 mg/g, 19.8mg/g,3.32 mg/g.(2) When 0.5g adsorbent was treated with solutions of Arsenic(Ш) in redistilled water at the concentrations of 0.2ppm,2.0ppm and 20.0ppm the adsorption equilibriums were reached separately after 7h,6h and 11h,the corresponding adsorption capacities were 3.4μg/g, 78.8μg/g and 403.5μg/g.When the dialysis solution of Arsenic(Ш) at the same concentration was tested,the adsorption equilibriums were reached after 11h,6h and 8 h respectively so that adsorption capacities were 8.9μg/g,8.4μg/g and 415.0μg/g correspondingly.(3) When 0.5g adsorbent YXA2, 3 was treated separately with dialysis solutions of Arsenic(Ш) at the concentrations of 0.2ppm, 2.0ppm and 20.0ppm during 1-11h,1-8h and 1-8h,the dynamic adsorption equilibriums were reached separately after 8h,6h and 7h,the corresponding dynamic adsorption capacities were 5.81μg/g,67.3μg/g and 411.0μg/g.While redistilled water was substituted for dialysis solutions the dynamic adsorption experiments respectively carded for 1-8h,1-8h and 1-11h and the adsorption equilibriums were reached separately after 6h,6h and 7h,the corresponding dynamic adsorption capacities were 5.85μg/g,78.3μg/g and 403.2μg/g.The experimental results of absorption kinetics of indicated that at the same adsorption volume the adsorption capacity curve was linear with increasing the arsenic(Ⅲ) concentration.The adsorption results of triethylene tetraamine-modified oxycellulose showed that:(1) when adsorption tests were carried at 37℃and pH7 in 5 h,static adsorption capacity of 0.5g adsorbent for urea(6g/L in dialysis solution),uric acid(1 g/L in redistilled water) and creatinine(0.1 g/L in dialysis solution) were 131.5mg/g,24.6mg/g,3.31mg/g respectively.(2) when 0.5g adsorbent was treated with urea,uric acid and creatinine for 9h three adsorption equilibriums were all reached after 6h and the corresponding adsorption capacities were 133.2 mg/g,24.9 mg/g,3.42mg/g.(3) The static absorptions of adsorbent YX3,4 for arsenic(Ш) was that the adsorption equilibriums were all reached after 6h when 0.5g adsorbent YX3,4 was treated with solutions of Arsenic(Ш) in redistilled water at the concentrations of 0.2ppm,2.0ppm and 20.0ppm,the corresponding adsorption capacities were 5.56μg/g,60.46μg/g and 436.71μg/g.(4) The dynamic absorptions of adsorbent YX3,4 for arsenic(Ш) gave a conclusion that when arsenic(Ш) concentrations were 0.2ppm,2.0ppm,20.0ppm in redistilled water the all adsorption equilibriums were reached after 5h in the presence of 0.5g adsorbent and equilibrium adsorption capacities were 5.33μg/g,59.03μg/g, 430.19μg/g respectively.The adsorption capacity increased linearly with increase of arsenic(Ш) concentration.(5) When 0.25g,0.5g and 0.75 g of adsorbent YX3,4 were treated with Cr(Ⅵ) in redistilled water at the concentration of 2.0ppm at 37℃for 1-7h,all dynamic absorption equilibriums were reached nearly after 6h and corresponding equilibrium adsorption capacities are 121.1μg/g,70.2μg/g and 41.0μg/g,which gave a decreasing tendency. In summary,the products can adsorb urea effectively in both static and dynamic absorption. And poly amino group also can absorb arsenic(Ⅲ) and Cr(Ⅵ) at different concentrations effectively under various environments.Since the performances in static adsorption,dynamic adsorption and adsorption kinetics are similar to related derivatives,these products have the potential to become new functional macromolecular materials.
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