【作者】 毛寅；

【导师】 陈家玮；

【作者基本信息】 中国地质大学（北京） ， 地球化学， 2011， 硕士

【摘要】 随着社会和经济的快速发展,我国地下水污染问题已日益突出,地下水污染带来的负面影响也日趋明显。针对其对于环境以及经济发展带来的严重影响,加强地下水的污染治理和对相关技术的开发利用越发迫在眉睫。地下水中六价铬Cr(VI)的污染已成为危害环境和人类健康的危险物质。在矿山、制革、电镀等行业的废渣、废液中铬浓度可超过国家标准限制的数百甚至上千倍。这些废渣、废液中的Cr(VI)可经过渗滤作用进入地下水体,由于Cr(VI)的毒性高、易迁移,对地下水造成严重的安全隐患。本文通过纳米零价铁对六价铬的还原固定的批实验研究,获得第一手实验数据,对纳米零价铁应用于实际场地修复提供实验依据,具有重要的理论依据和应用价值。零价铁还原去除Cr(VI)的影响因素包括Fe0颗粒的粒径、Fe0的投加量、Cr(VI)的初始浓度、反应温度以及Fe0的老化程度等。本文通过设计单因素和正交实验,运用纳米零价铁(nZVI)还原去除水中的Cr(VI),探讨了零价铁粒径、纳米零价铁投加量、六价铬初始浓度、温度、纳米零价铁老化程度对还原反应的影响作用,并对反应进行了还原条件的优化选择。获得的实验结果和结论如下:(1)单因素实验表明,较细的Fe0颗粒,较大的Fe0用量,较高的反应温度以及较新鲜的Fe0对Cr(VI)还原反应的进行具有促进作用。(2)粒状(平均粒径0.5-1mm)零价铁在投加量为纳米零价铁数十倍时,去除效率只达到纳米零价铁去除效率的2-3%;(3)三因素三水平正交实验获得不同因素对零价铁去除六价铬的影响因素从大到小依次为纳米零价铁投加量、六价铬初始浓度、温度。在正交实验中,得到的最佳去除条件是在水体中含有50mg/L Cr(VI)时,投加2g/L纳米零价铁在25℃下去除效果最佳。更多还原

【Abstract】 With the fast development of economy and society, the problem of groundwater pollution has become increasingly prominent issues, and the negative impact of polluted groundwater is also becoming more serious. It is extremely urgent to control contaminated groundwater and explore remediation technology.Hexavalent chromium, Cr(VI), is a pollutant in groundwater and hazardous to human health. In the residual water of mining, tanning, electroplating and other industries, the concentration of Cr(VI) is hundreds times more than limitation value of national standards. Cr(VI) could infiltrate into the groundwater and cause serious security risks because of its high mobility and toxicity.This thesis aimed to remove hexavalent chromium by zero-valent iron nanoparticles. Through the batch experiments, first-hand data were got and these could provide the basis for the in-site groundwater remediation using nano zero-valent iron.The effect factors of Cr(VI) removal contain Fe0 particle size, Fe0 dosage, initial Cr(VI) concentration, reaction temperature and Fe0 aging time. Single factor experiments and orthogonal experiments were both designed for reduction of Cr(VI) from water by nano zero-valent iron (nZVI). The factors of nZVI particle size, nZVI dosage, initial concentration of Cr(VI), temperature, nZVI aging time were discussed and optimized.The results showed in the following.(1) Smaller Fe0 particles, larger Fe0 dosage, higher temperature, and fresh Fe0 can stimulate the reaction.(2) For the granular zero-valent iron (average particle size 0.5-1mm), when its dosage is ten times of nZVI, removal efficiency of Cr(VI) only reaches 2-3% by nZVI.(3) From three factors and three levels in orthogonal experiments, the importance order of factors for Cr(VI) removal is nZVI dosage, initial Cr(VI) concentration and the temperature. The optimal removal conditions is that when the water contains 50mg/L Cr(VI), 2g/L nZVI at 25℃was added.更多还原