端氨基超支蔗渣纤维素吸附水中重金属离子机理研究

Nowadays,heavy metals are among the most important pollutants in source and treated water and are becoming a severe public health problem.These metals ions can be harmful to aquatic life,and water contaminated by toxic metal ions remains a serious public health problem for human health.Consequently ,it is urgent to find new technologies for removing heavy metal ions from wasterwater.The commonly used treatment of heavy metals ions pollution technology is adsorption method. As a highly branched, water-soluble monodisperse polymer, the amino-terminated hyperbranched polymer which is rich in amino and imino groups is grafted on the cellulose moleculas to make it insoluble in water. In this project, utilizing the bagasse cellulose, an abundant nature resouce in Guangxi, the amino-terminated hyperbranched cellulose was prepared by adopting the cellulose modification technology. The kinetic mechanisms were studied for its treating the mixture toxic heavy metal ions in wastewater. Provide the basis for the determination of wastewater treatment process. Characteristic analysis of modified celluose and the sediment after adsorpting process were carried out for offering evidence of its resource utilization. After the alkali pretreatment process, the bagasse was reacted with other chemical reagents like methyl glyoxylate, and ethanediamine in order to synthesis the amino-terminated hyperbranched cellulose.Then the modern analytical techniques such as FTIR,BET-N2 adsorption method,XRD and SEM,were used and were characterized by functional group,specific surface area,surface structure and morphology,etc.This project studied the impacts of the adsorbent dosage pH,contact time and other factors,and emphatically studied the adsorption thermodynamics and kinetics by static adsorption experiments,and the adsorption properties of Hg Pb,Cu,Zn ions in aqueous solution by amino-terminated hyperbranched celluose.

本项目利用广西丰富的蔗渣资源，采用纤维素改性技术，制备出端氨基超支蔗渣纤维素，并研究将其处理复合重金属废水的吸附热力学和动力学机理。以蔗渣为原料，经碱化、氧化处理制备双醛蔗渣；用甲基丙烯酸甲酯、乙二胺制备端氨基超支化合物，将其接枝到双醛蔗渣上，合成出端氨基超支蔗渣纤维素重金属吸附剂。采用扫描电镜、红外光谱、X 射线衍射、元素分析等对产物的结构和性质进行表征。将端氨基超支蔗渣纤维素应用于处理模拟含Hg、Pb、Cu、Zn 等复合重金属离子废水，考察单一和复合重金属离子的初始浓度、pH、投加量、温度等因素对去除率的影响。探究端氨基超支蔗渣纤维素对重金属离子的吸附特征，包括吸附参数、吸附热、吸附类型、吸附模型等机理。广西的冶矿采矿业重金属污染严重，本项目利用广西的特色资源蔗渣，研究重金属微污染的深度处理技术，为广西的重金属污染的深度治理，提供基础理论依据。

重金属污染的治理已经越来越受到广泛的关注。纤维素分子通过化学改性后可成为性能良好的吸附剂。针对含氮纤维素以及超支化合物的自身特点，选用蔗渣的氧化产物双醛蔗渣纤维素作为原料，设计并合成了一种含有端氨基超支化合物结构的蔗渣改性重金属吸附剂，对产物吸附重金属离子的吸附性能进行了研究。具体内容如下：. 制备出预处理产物碱蔗渣纤维素，制备出氧化产物双醛蔗渣纤维素。控制KIO4溶液的浓度为2.5g/L，溶液与碱蔗渣的浴比为30，体系pH介于2.0-2.5的范围内，且反应温度为45℃时，反应1小时。以乙二胺和丙烯酸甲酯为原料，合成出水溶性端氨基超支化合物，并通过醛基的胺化还原反应将其接枝在双醛蔗渣纤维素上，制备出端氨基超支化合物改性蔗渣纤维素。采用FTIR、SEM、XRD等对进行表征与分析。选取pH、金属离子初始浓度、吸附剂用量以及吸附时间作为研究对象，考察了四个变量对于HBPN-g-BC吸附铜镉离子性能的影响。吸附为近中性（pH=6-7）；对浓度为10mg/L的铜或镉离子溶液，吸附剂投加量分别为0.1g/L和0.2g/L；产品对低浓度Cd2+或Cu2+的去除效率都比较高，对Cd2+的吸附30.0min内可达平衡，去除率达75%以上，而对于Cu2+的吸附在60.0min内达到平衡。. 用双醛纤维素与三乙烯四胺制备三乙烯四胺基纤维素并表征，对 Cu2+和Cr(Ⅵ)进行单一和混合离子的吸附研究。端氨基超支化纤维素对Cu2+、Cr(VI)的等温吸附过程可以用Langmuir、Freundlich和Temkin等温模型进行描述。 . 广西的冶矿采矿业重金属污染严重，本项目利用广西的特色资源蔗渣，研究重金属微污染的深度处理技术，为广西的重金属污染的深度治理，提供基础理论依据。

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