【作者】 张兴松；

【导师】 辛梅华；

【作者基本信息】 华侨大学 ， 环境工程， 2008， 硕士

【摘要】 天然高分子聚合物壳聚糖(CTS)以其原料丰富、无毒和可生物降解等优点,在环境污染治理中倍受关注。为改善CTS的耐酸性能和吸附性能,本文采用反相悬浮法制备环氧氯丙烷交联CTS微球,再用氯乙酸和α-酮戊二酸进一步羧化改性,用FTIR、XRD、SEM等进行表征,并用于吸附2,4-二硝基酚化合物研究。采用反相悬浮法制备交联CTS微球,再用氯乙酸改性,制得环氧氯丙烷交联氯乙酸改性CTS微球,并用于吸附2,4-二硝基酚研究。实验结果表明:氯乙酸改性交联CTS微球具有较好的耐酸碱性能,对2,4-二硝基酚的吸附在pH 3.6的条件下,吸附在瞬间就能达到平衡,吸附量为230 mg·g-1,优于未改性的CTS原料。吸附量随酚浓度的变化符合Freundlich等温方程。采用α-酮戊二酸代替氯乙酸作羧化试剂,与CTS反应生成Schiff碱,再用NaBH4还原制备改性CTS微球,考察在CTS上引入两个-COOH对2,4-二硝基酚的吸附性能。结果表明:α-酮戊二酸改性交联CTS微球耐酸碱性能良好,对2,4-二硝基酚具有良好的吸附性能,在温度30℃,pH3.6,吸附在瞬间就能平衡,吸附量达372mg·g-1,优于氯乙酸改性CTS微球。吸附量随酚浓度的变化符合Freundlich等温方程。洗脱再生实验结果表明:两种改性CTS微球都具有良好的重复使用性能。采用反相HPLC-紫外检测法研究在多种有机污染物共存的情况下,氯乙酸和α-酮戊二酸改性CTS微球对有机物的同时吸附。建立了测定七种有机污染物的最佳色谱条件。实验结果表明,在共存有机物浓度相近情况下,改性CTS微球均优先吸附2,4-二硝基酚。采用正交实验设计对α-酮戊二酸改性CTS微球的制备条件进行了分析和优化。结果表明,改性的最佳条件是:α-酮戊二酸/CTS的摩尔比为2:1,反应温度40℃,反应时间4h,制得的改性CTS微球吸附量达433mg·g-1。更多还原

【Abstract】 In order to enhance the acid resistance and adsorption abilities of chitosan, in this paper, modified chitosan microspheres were prepared by reversed-phase suspension, than were crosslinked with epichlorohydin and modified by monochloroacetic acid orα-ketoglutaric acid. The structure of modified chitosan microspheres was characterized by FTIR、XRD and SEM, and microspheres were applied to adsorb 2,4-dinitrophenol from aqueous solution.The crosslinked chitosan microspheres were prepared by reversed-phase supension, than modified with monochloroacetic acid, and the adsorption for 2,4-dinitrophenol was investigated. The experimental results indicated that the microspheres modified with monochloroacetic acid were insoluble in acidic and basic solutions. In the solution of pH 3.6,the adsorption reached to 230mg·g-1 instantaneously, and were able to adsorb 2,4-dinitrophenol better than chitosan. The adsorption data of 2,4-dinitrophenol on the modified chitosan microspheres was fitted to the Freundlich isotherms.The chitosan microspheres was prepared by reducing Schiff`s bases formed from the reaction ofα-ketoglutaric acid and crosslinked chitosan. The adsorption of chitosan microspheres with two -COOH groups for 2,4-dinitrophenol was investigated. The experimental result indicated that in an aqueous solution at pH 3.6,the adsorption reached to 372mg·g-1 in 30 mins. The micropheres modified withα-ketoglutaric acid were able to adsorb 2,4-dinitrophenol better than that modified with monochloroacetic acid. The adsorption data of 2,4-dinitrophenol on the modified chitosan microspheres was fitted to the Freundlich isotherm.The experimental results of elution and regeneration showed that both of the two kinds of modified chitosan microspheres had good reusing capability.The competitive absorption of the modified chitosan microspheres to the organic contaminators was studied by RP-HPLC with UV detection. The optimal chromatographic conditions for the separation and detection of seven organic compounds have been obtained. The experimental results indicate that the modified chitosan microspheres can adsorb 2,4-dinitrophenol in water firstly when the concentration of seven organic compounds is similar.The synthesis conditions of chitosan microspheres modified withα-ketoglutaric acid were optimized by orthogonal experiments. The results indicated that the adsorption capability of the modified microspheres could reach to 433mg·g-1when theα-ketoglutaric /chitosan was 2/1(mol/mol), reaction temperature was 40℃and reaction time was 4 hours.更多还原