【作者】 刘小帅；

【导师】 马伟；

【作者基本信息】 大连理工大学 ， 无机化学， 2008， 硕士

【摘要】 铜被认为是对环境有毒害的重金属离子,随着工业的发展和铜的大量工业应用,每年将产生数以万吨的含铜工业废水。目前处理重金属离子的方法很多,比如化学沉淀法,离子交换法以及电解法等,但由于产生大量污泥和导致二次污染,应用受到限制,而膜吸附法由于操作简便、成本低等优点成为近年来研究的热点和重要课题。利用膜作为吸附剂净化工业废水和回收重金属离子是一个很有潜力和价值的选择。首次研究了壳聚糖共混膜来做重金属的吸附剂并测试了相关性功能,发现了膜吸附重金属后,膜的颜色与该重金属的水合离子颜色一致,该膜有用于快速检测重金属的潜力。并研究了共混膜吸附Cu(Ⅱ)的吸附机理。用溶液共混法制备壳聚糖(CS)与改性剂(YC)共混膜,采用红外光谱(FT-IR)、X—射线衍射(XRD)、扫描电镜(SEM)等多种表征手段对膜的结构形态和物理化学性质进行了研究,并测定了吸水率。结果表明:这种共混膜性能稳定,并且共混膜提高了它对Cu(Ⅱ)的吸附。利用合成的壳聚糖共混膜研究了溶液pH值,时间,温度,初始浓度,离子强度,吸附剂加入量等因素对Cu(Ⅱ)吸附的影响,实验结果表明在强酸性和碱性条件下不利于吸附,在pH=5-6时最好,去除率最高达到92.92%,吸附速度较慢,吸附能力随吸附剂加入量增大而变小,随离子强度的增大先增大后变小,随初始浓度增大而增大,随溶液温度升高略有下降;阳离子Co(Ⅱ),Ni(Ⅱ)对吸附没有影响,CS/YC膜吸附选择性良好。通过利用Langmuir和Freundlich吸附模型对比,Freundlich模型符合较好。另外,对吸附剂的解吸、再生和重复利用过程进行了研究,结果表明在0.2%硫脲—0.02 M HCl溶液中的解吸是一个快速过程,效率高,膜吸附剂能够再利用,同时也便于回收铜。在此基础上,利用XRD,SEM方法表征CS/YC膜,研究了吸附前后吸附剂表面的变化规律以及吸附特征曲线,进而推断吸附机理为主要是物理吸附和表面配位机制。更多还原

【Abstract】 The copper is recognized toxic heavy metal ions for environment and it will produce thousands tons of industrial wastewater contained copper every year with the development of industry and copper application broadly. The methods which have been used to remove heavy metal ions, such as chemical precipitation, ion-exchange, and electrolysis have been found to be limited, since they often involve amount of discharge sludge or secondary wastes which present treatment problems. The use of adsorption is becoming research hot spot and important subject in recent years due to its low cost and convenient operation. There in the use of membrane as adsorbent for heavy metal offers a potential alternative to existing methods for purification and recovery of these components from industrial wastewaters. CS/YC membrane usually used as food containers and table, medical material, water and alcohols separate membrane, this paper use the membrane as sorbent for heavy metal, find the membrane’s color was changed after adsorption, the color was the same as the hydrated cation, this membrane has the potential of detect heavy metal ions rapidly, and study on the mechanism of Cu(II) onto the CS/YC membrane.The blend membrane of chitsan(CS)/modifier(YC) has been prepared. The structure morphology, the physical and chemical characteristics of the membranes were obtained by FT-IR, XRD and SEM. And the water absorption has beed tested. As a result, there were some interaction between YC and chitosan, which showed that blend of YC and chitsan was helpful to improve the adsorption capacity of the Cu( II).The effects on Cu( II )adsorption of pH, time, temperature, Cu( II) initial concentration, ionic strength, dosage were investigated by CS/YC membrane. The results show that pH=5-6 is the optimal condition for Cu(II) adsorption, the Cu( II )removal efficiency is 92.92%, strong acidic and alkaline solution are both unfavourably for adsorption. The adsorption process happened slow, adsorption capacity decreased with sorbent dosage increased, with ionic strength incresing first hoist and then falling, adsorption capacity increased with high initial concentration ,and decreased with solution temperature; coexisting canon of Co( II), Ni (II)have no effect on Cu( II )adsorption, which illustrated selectivity is good. Experiments data were analyzed by Langmuir model and Freundlich model, it noted Freundlich isotherm was better described the adsorption process. In addition, the process of desorption sorbent regeneration and recycle tests were also studied using 0.2% thiourea—0.02 M HC1 solution as regeneration agent, the results illustrated the desorption process complete quickly and efficiency, CS/YC membrane can be reused many times in recovery of Cu( II).Finally, the adsorption mechanism of Cu( II) onto the CS/YC membrane was investigated by XRD, SEM and analyzed according the performance of adsorption isotherm,it suggested that the main action role is physical adsorption and outer-sphere complex.更多还原