【作者】 王慧；

【导师】 刘建；

【作者基本信息】 长安大学 ， 环境工程， 2008， 硕士

【摘要】 地壳中的砷通过风化、侵蚀、溶解等自然作用以及打井取水、灌溉、采矿、化工等人为活动,已大量释放到天然水中,主要进入地下水,其次进入地表水,含砷浓度的高端范围已达到0.1~2mg/L以上。砷化合物容易在人体内积累,造成急性或慢性中毒,是造成人类患肺癌、皮肤癌和其它内脏癌症的主要威胁之一。中国、美国、日本以及WTO等均已经把饮用水含砷量标准从0.05mg/L降到0.01mg/L。因此,为了严格控制饮用水中的砷含量,保障人民身体健康,研究和开发新的除砷技术已势在必行。目前脱除水中砷的研究也比较多,但都不同程度存在缺陷,因而限制了其在实际中的应用。因此,探索经济、有效的深度除砷材料和工艺,对含砷饮用源水处理是一项很有价值的课题。本文在对已有除砷方法和工艺进行分析、研究的基础上,旨在利用多孔性、容易改性的分子筛或类似于分子筛的骨架上的笼状结构,将Fe3+通过离子交换吸附,固载在其骨架上,实现改性,再利用改性后的吸附剂具有大的活性表面积,以及砷阴离子与Fe3+的强配位能力,提出一种基于配体交换的固液分离除砷思路。通过实验研究,获得了新的从微量含砷水中去除砷的材料。实验研究中,分别对改性分子筛、改性活性炭以及改性高岭土三种除砷剂载体的合成、改性条件以及除砷剂去除水中As(V)的性能进行了研究,对除砷剂除砷条件、干扰条件和工艺条件和吸附机理等进行了详细的探讨:三种除砷材料均有操作简便、干扰少以及不对环境产生二次污染等特点。其中,改性分子筛和改性活性炭具有除砷后易从水中分离的特点,而改性高岭土除砷剂对水中As(V)的吸附容量在三种除砷材料中最大,处理后的水可达到国家饮用水标准甚至更低,另外从资源综合利用,成本较低,提高环境效益方面考虑,改性高岭土除砷具有重要的意义,有很高的实用价值。除砷剂除砷过程可描述为:扩散-反应-扩散过程,其机理实质是配体交换反应过程。文章最后通过参数设计计算,提出了集中式含砷水除砷装置,为新的深度固液分离除砷方法提出了理论依据和实践基础。更多还原

【Abstract】 Though nature functions as well as the well drilling weathering, erosion, dissolution, and artificial activity such as water wells, irrigation, mining, chemical industry, arsenic in lithosphere has released into the natural water ,mainly into the groundwater, followed by access to surface water. The arsenic concentration has gone beyond 0.1 ~ 2 mg / L. Arsenide is easily accumulated in the human body, causing acute or chronic poisoning. It is one of the major threats caused human suffering from lung cancer, skin cancer and other cancers visceral. The arsenic quantity standard in drinking water has been dropped from 0.05mg/L to 0.01mg/L in China, the US, Japan and the WTO. Therefore, in order to strictly control the content of arsenic in drinking water, protect people’s health, it is imperative to find a new method of removing arsenic from water. At present, a lot of study has been done in this area. Nevertheless, the method has limited used in practice for its shortcomings in varying degrees. Therefore, it is a subject of great value to investigate the cost-effective materials and methods for arsenic removal.In this paper, a detail analyzing and discussion of the existing arsenic removal methods is made in foundation of much reading and lots of experiments. Taking advantage of porous, easily modified molecular sieve or similar to the skeleton on the cage-like structure, it can be obtained by loading Fe3+ on the skeleton of the material. By the complexation of Fe3+ and H2AsO4—or HAsO42- , arsenate can be removed from high arsenic containing water.The optimum condition of synthesis, modification, and the carrier behavior have been discussed in this study , separately from modified zeolite, modified activated carbon and modified kaolin. In-depth research has been carried on in arsenic removal conditions, disturbed conditions, technological conditions and adsorption mechanism. All of the three arsenic removal materials have the advantages of simple operation, less interference and non-secondary pollution the environment. The modified zeolite and the modified activated carbon could be separated from the water easily. The modified kaolin has the maximum arsenical absorption capacity in water among three materials. The water can meet the state drinking water standards or even lower after treatment by it. In addition, It has the vital significance and high practical value to arsenic removal. The mechanism of arsenic removal is a process of ligand exchange. The process can been described as three steps: scatter- react- scatter. Finally, through the design parameters, centralized water equipment of arsenic removal has been designed. It takes a new depth-solid-liquid separation method to arsenic removal both in theory and practice.更多还原