核桃壳和改性柚子皮对水中Cr(VI)的吸附特性研究-毕业论文（设计）.doc

w 毕业论文 题　　目 核桃壳和改性柚子皮对水中Cr(VI)的吸附特性研究 姓 名 指导教师 核桃壳和改性柚子皮对水中Cr(VI)的吸附特性研究 摘要 ：六价铬离子是一种危害极大的重金属离子污染物常规混凝一沉淀、生化法处理含铬废水难以达到排放标准。本实验选取吸附法为研究方向，并选择核桃壳和柚子皮作为吸附剂，以展开活性炭吸附重金属离子的研究。本研究采用自行配制的重铬酸钾溶液进行实验，分别进行了核桃壳和柚子皮吸附Cr(VI)的最佳震荡时间、最适吸附剂的投加量、最适金属溶液的初始浓度及最佳 pH 值的探究实验。 结果表明：当pH=5，Cr6+初始浓度为35μg/ml，吸附时间为45min，吸附剂的投加量为6g/L时，柚子皮的吸附效果最佳，去除率达到99．88％。对于Cr(VI)浓度为20mg/L的50mL水样，当温度为25℃，介质 pH值为1．0、吸附时间为180min处理废水时，核桃壳的吸附效果最佳，Cr(VI)的去除率可以达到99．3％。 关键词：吸附；Cr(VI)离子；核桃壳；改性柚子皮 Study on Adsorption Of Cr(VI) in Water by Modified Shaddock Peel and Walnut Shells Abstract:The influences of factors such as pH value，contact time，adding dosage of adsorbent and Cr6+ initial concentration on the adsorption results were discussed through the adsorption experiment on shaddock peel modified by isopropano1．The results indicated that modified shaddock peel had good adsorption to Cr6+．The optimal conditions of absorption were as follows：the value of pH was 5。The initial concentration of Cr6+ was 35μg／ml，the reaction time was 45min，and the dosage of absorbent was 6g／L，the adsorption rate of Cr6+could be up to99．88％． The effect on treatment of 50mL simulated wastewater whose concentration of Cr(VI) is 20mg·L-1 by walnut shells are studied by means of static absorption under different conditions．The experimental results show that when the producing area of the is Xin jiang，the temperature is 25℃，the diameter of xinjiang walnut shell is1．0-1．6mm ，the adsorbent dosage is1．0 g，the optimum condition is pH =1．0，adsorption time is about 180minutes，the adsorption rate of Cr(VI) can be up to99．3％．The concentration of Cr(VI) is 0．14 mg·L after adsorption，which meets the Integrated Wastewater Discharge Standard GB8978-- 1996 standards for the first-class of pollutants．The adsorption of Cr(Ⅵ ) rises as the temperature rises．In the meantime，the Adsorption isotherm ，Langrnuir adsorption isotherm and Freundlich ad