【作者】 董爱琴；

【导师】 尹业平；

【作者基本信息】 华中农业大学 ， 农药学， 2009， 硕士

【摘要】 随着我国现代工业的发展,工业废水的排放量越来越大,对我国水资源的污染也日益严重,所以对重金属废水的处理得到更多的关注。因此,研究制备既能高效处理工业废水污染,又能有效分离、重复使用的吸附材料成为了研究热点。本文以玉米淀粉为原料,通过双醛淀粉与乙二胺反应,制备氨基淀粉并将其负载到膨润土上。研究了双醛淀粉和氨基淀粉的制备条件。同时从吸附容量、吸附动力学、等温吸附、介质酸度影响以及吸附剂再生等方面研究了改性淀粉吸附剂对Cu²⁺、Cr（Ⅵ）两种重金属离子的静态吸附性能。其主要结果如下:1、研究了双醛淀粉的制备条件,反应温度和pH值是影响产物醛基含量的主要因素。采用了测定醛基含量的新方法-电导法,与传统的滴定法比较可以快速准确的得出醛基含量。确定氧化条件为:反应时间为3h、温度为35℃、pH为1.5-2、高碘酸钠浓度为0.6mol/L、高碘酸钠与淀粉摩尔比为1.1:1。在此条件下制得的氧化淀粉的醛基含量达80%。2、采用双醛淀粉作为原料制备氨基淀粉,并研究了氨基淀粉的制备条件。pH值和乙二胺浓度是影响产物的氮含量的主要因素。确定反应条件为:反应时间为2h、反应温度为35℃、pH为5.5、乙二胺浓度为0.6mol/L、乙二胺与双醛淀粉摩尔比为4:1。在此工艺条件下制得的氨基淀粉氮含量可150%,比传统的醚化法氮含量高将近一倍。3、首次制备了氨基淀粉与膨润土的复合物,并证实了负载的可行性。从膨润土、膨润土与氨基淀粉复合物的IR和XRD分析可知,蒙脱石的片层结构未发生变化,氨基淀粉仅仅吸附在蒙脱石的内外表面。4、研究了氨基淀粉和氨基淀粉膨润土复合物对Cu²⁺、Cr（Ⅵ）的吸附性能。结果表明:氨基淀粉相比复合物来说对Cu²⁺、Cr（Ⅵ）较大的吸附容量;氨基淀粉对Cu²⁺的吸附较符合二级动力学规律,而对Cr（Ⅵ）的吸附较符合一级动力学规律;两种吸附剂对Cu²⁺、Cr（Ⅵ）的吸附行为符合Langmuir模型;结合pH对吸附性能的影响结果,可推测吸附过程是化学吸附;吸附剂的再生性研究表明,用稀盐酸做再生剂,氨基淀粉和复合物可重复使用。5、通过对吸附剂吸附重金属前后的IR和XRD图谱分析,氨基淀粉与重金属离子是通过配位作用结合的,复合物与金属离子之间既有离子交换作用又有配位作用。氨基淀粉和复合物对重金属离子的吸附属于化学吸附。对吸附剂吸附重金属的机理研究有待进一步研究。更多还原

【Abstract】 With the development of modern industry, more and more industry waste water is piping out, which results in the pollution of water. Thus the removal of toxic and polluting heavy metal ions from waste water has received much attention in recent years. Therefore, researches were empHasized on preparing the high-powered chelating adsorption material that could not only remove heavy metal ions from waste water effectively, but also separate and recycle heavy metal ions effectively.In this article, modified heavy metal adsorbents was synthesized with corn starch as raw materials, through the dialdehyde starch reaction with ethylenediamine and loading amino-starch on bentonite. The optimization synthesis condition of dialdehyde starch and amino-starch were determined. And the static state absorbent activity to heavy metals such as Cu²⁺ and Cr（VI） by amino starch and amino starch bentonite blends was studied in terms of adsorptive capacity, adsorptive kinetics, adsorptive isotherm, medium acidity, adsorptive regeneration.The results are as follows:1. The study of dialdehyde starch preparation indicated that reaction temperature and pH were main factors on the impact of aldehyde content. We took the new determination method on aldehyde content- conductivity method, which can deteimine aldehyde content fast and accurately comparaing to the traditional titration. The optimized synthesis conditions were as follows: reaction time 3h, reaction temperature 35℃, pH 1.5-2, sodium periodates concentration 0.6mol / L, and starch sodium periodate molar ratio 1.1:1. And under these conditions, the aldehyde content of oxidized starch obtained to 80%.2. We prepared amino-starch using Dialdehyde starch as raw materials, and studied preparation conditions of amino starch. Ethylenediamine concentration and pH were main factors on the impact of nitrogen content. The optimized synthesis conditions were as follows: reacting time 2h, reacting temperature 35℃, ethylenediamine concentration 0.6mol/L, ethylenediamine dialdehyde starch ratio 4:1. And under these conditions, the nitrogen content of amino starch obtained to 150%, which was nearly twice of the traditional ether method.3. We prepared bentonite amino starch blends for the first time, and confirmed the feasibility of loading amino starch on bentonite. From the IR and XRD spectras of bentonite and amino starch bentonite blends we can find that the lamellar structure of montmorillonite did not change, and amino starch only adsorbed on the internal and external surface of montmorillonite. 4. Adsorption ability of amino starch and bentonite loaded amino starch for Cu²⁺, Cr（VI） were studied. The results showed that: the saturating adsorptive capacity of amino starch to Cu²⁺, Cr（VI） is greater than amino starch bentonite blends; The amino starch adsorption for Cu²⁺ is more fit to the second-order kinetics law, and its adsorption for Cr（VI） is more fit to the first-order kinetics law; the adsorption processes of the two absorbents for Cu²⁺, Cr（VI） are a course of heat adsorption and more fit to Langmuir model; combining with PH on the adsorption properties, we can find that the adsorption process may be surmised chemical adsorption; with diluted hydrochloric acid regeneration agent, amino starch and amino starch bentonite blends can be reused.5. The IR and XRD spectrums adsorbents adsorption of heavy metals before and after shows that, amino starch combined with heavy metal ions by coordination and amino starch bentonite blends combined with heavy metal ions by spectrometer exchange and chelating. The adsorption of the two absents for Cu²⁺ and Cr（VI） belongs to chemical adsorption and mechanisms of the adsorption for heavy metals will be studied furtherly.更多还原