ZnⅡ废水试验研究-北京大学教务部.DOC

天然锰钾矿处理含Cd(Ⅱ)、含Zn(Ⅱ)废水实验研究 Experimental Treatment of Cd(Ⅱ)-bearing and Zn(Ⅱ)-bearing wastewater by Natural Cryptomelane 地球与空间科学学院 99本 唐元之 摘 要 重金属污染是当前水体污染的一个重要方面。本文论述了处理水体重金属污染的重要性与主要的重金属污染物，以及利用天然锰钾矿处理重金属污染的可行性。通过开展利用天然锰钾矿去除废水中重金属离子Cd(Ⅱ)、Zn(Ⅱ)的实验研究，认为天然锰钾矿作为一种环境矿物材料，在处理重金属废水方面具有很大的潜力。对采自湖南湘潭锰的锰钾矿进行粉碎分级。通过开展锰钾矿去除重金属离子Cd(Ⅱ)、Zn(Ⅱ)的实验研究，确定锰钾矿对Cd(Ⅱ)的去除反应平衡时间在15个小时以上。对影响天然锰钾矿去除量的因素进行探讨，结果表明：对于Cd(Ⅱ)，溶液pH值是影响去除量的主要因素；外加电解质对去除量的影响主要体现在溶液中是否存在与重金属离子配合强的配体离子，高浓度强配体离子的存在将很大程度上降低锰钾矿对重金属离子的去除量；矿物粒径的大小也在很大程度上影响去除量，粒径越小，去除量越高。对于Zn(Ⅱ)，去除量随试样粒径的变化几乎没有变化。介质的pH值和外加电解质的浓度对去除量影响也不大。说明锰钾矿对Zn(Ⅱ)的吸附属于化学吸附。反应前后溶液的pH值都有不同程度的变化。吸附等温实验研究表明：对两种金属离子的去除都能很好的符合Langmuir吸附等温线，在所给实验条件下，所用锰钾矿矿样的理论最大去除量对Cd(Ⅱ)为5.54mg/g，对Zn(Ⅱ)为72.5mg/g。本次研究证实了天然锰钾矿是一种很好的处理水体中重金属离子污染的环境矿物材料。 关键词：环境矿物材料；天然锰钾矿；重金属废水；吸附 Abstract The contamination of water by heavy metals plays an important role in water pollution. This thesis discusses the importance of treating with heavy metals, the main heavy metals and their toxicity. After the experimental treatment of Cd(Ⅱ)-bearing and Zn(Ⅱ)-bearing wastewater by natural cryptomelane, we conclude that as a kind of environmental mineral materials, cryptomelane has great potential in disposing aqueous heavy metals. The natural cryptomelane from Hunan was crushed and sorted by grain size. The equilibrium time was determined after investigating the adsorption of heavy metal ions Cd(Ⅱ) and Zn(Ⅱ) by natural cryptomelane. For Cd(Ⅱ), it needs at least 15 hours to reach the equilibrium. Through a series of experiments, the main influencing factors of the adsorption were studied. The investigation indicates that: for Cd(Ⅱ),the disposal capacity is mainly influenced by the pH values. The existence of other electrolytes and the grain size of the mineral also affect the disposal capacity greatly. For Zn(Ⅱ), the disposal capacity almost has no relation with the grain size, and changes little with the change of pH value and the concentration of NaNO3. For both Cd(Ⅱ) and Zn(Ⅱ), the pH values a