【作者】 张雪乔；

【导师】 姚秉华；

【作者基本信息】 西安理工大学 ， 环境工程， 2004， 硕士

【摘要】 水是一种极为宝贵的资源，水质污染除有机物污染外，重金属的污染也愈来愈引起人们的关注。六价铬毒性大、危害性强、能致癌，就电镀工业而言，每年要排放大量的含铬废水。但铬及其化合物又是重要的化工原料，因此寻求一种快速、高效的含铬（Ⅵ）废水治理技术尤为必要。 含铬（Ⅵ）废水处理方法较多，本论文就液膜分离法、溶剂萃取法、药剂还原法及吸附法展开进一步探索，考察各种因素对Cr（Ⅵ）去除效果的影响，从而确定最佳实验条件，并应用于模拟电镀废水中Cr（Ⅵ）的去除，评价不同处理方法的优块点，具体研究工作如下： （1）乳化液膜分离 在乳化液膜体系的研究中，首先，对TBP—Span80—煤油的乳化液膜体系进行了实验，主要考察外水相pH值、内水相浓度、载体用量、表面活性剂浓度、油内比以及乳水比等因素对Cr（Ⅵ）迁移效果的影响；其次，改进液膜体系，考察TBP／TOA—Span80—煤油复合液膜载体对Cr（Ⅵ）的迁移特性的影响，结果表明，该体系可有效迁移富集Cr（Ⅵ），在V_煤油：V_TBP：V_TOA：V_Span-80：V_液体石蜡=85：5：3：3：4，内水相NaOH为0.5mol／L，外水相pH值为1.0，油内比1：1，乳水比20：100的条件下，迁移率达94.1％。根据界面化学和溶质扩散理论，建立了乳化液膜传质数学模型并进行了实验检验，发现该模型与实验结果能够较好的吻合。摘要 （2）溶剂萃取法 以煤油为萃取溶剂，TBP为萃取剂，十六烷基三甲基澳化钱（C TMAB）为协萃剂，考察萃取剂浓度、水相酸度、萃取时间等因素对Cr(VD萃取率的影响。在40%TBP、1 .smol/LHZSO;、0.lmol/LKZSO;、8.0xl0一smol/LCTM^B条件下，应用于模拟电镀废水，cr（VI）去除率可达83.4%。 （3）药剂还原法井’以俪多。，为还原剂，主要考察了还原pH值、投料比等因素对cr（vI）还原的影响。结果表明，对于4omg/LCr（Vl）、25.omg/LCu（11）、15.omg/LZn（11）和lo.omg/LNi（11）废水，在pH2.74、投料比为l:6的条件下，cr（Vl）去除率可达100%。 （4）吸附分离 采用活性炭为吸附剂，进行静态和动态吸附分离实验。结果表明，在静态实验条件卜，对于4o.omg/LCr（Vl）溶液，投加0.459活性炭，吸附sh，Cr（VI）去除率达92.0%。Cr（V一）静态吸附服从Freundlich方程:q=55.8 co，”8;在动态实验条于1几卜，当流速为lmL/min时，对于loo.omg/LCr（VI）溶液，测得穿透时I’ed为6h，应用于含Cr（VI）废水，去除率达98.3%。活性炭可通过20.0%NaoH再生，重复使用3次，吸附效果未发生明显变化。同时还对活性炭的表面修饰进行了探讨。更多还原

【Abstract】 Water is such a valuable natural resource that people pays more and more attention to heavy metal pollution besides the organic compounds in wastewater. Cr(VI) is a kind of carcinogen, famous for its toxicity and harmfulness. In respect to electroplating industry, a large amount of wastewater containing Cr(Vl) and its compounds which are important industrial raw materials is discharged every year, so it is very urgent to find one fast, high-efficient method to dispose it.In this paper, the several methods such as Liquid membrane separation, solvent extraction-, reduction and adsorption were studied for the wastewater treatment containing Cr(VI), respectively. The effects of various conditions on the transport rate of Cr(VI) were investigated and the optical conditions were obtained. Then the several methods were applied to the simulated electrodynamics wastewater containing Cr(VI) and other metal ions. Finally, the advantage and disadvantage of each method was appraised. The experimental results in detail is as follows:(1) Emulsion liquid membrane separationFirstly, the transport rate of Cr(VI) through ELM used TBP as the mobile carrier and Span80 as the surfactant, was studied by the Emulsion liquid membrane system. The effects of various parameters, such as the pH values in external water phase, the concentration of NaOH in inner water phase, carrier concentration, surfactant concentration, the Roi values and Rew, values were investigated; Secondly, the transport process of Cr(VI) through ELM used TBP and TOA as multiple carriers, Span80 as thesurfactant was studied. The results showed this ELM system was effective on Cr(VI) enrichment, and the transport rate could be attained to 94.1%, when Vkerosene : VTB?: VTOA: Vspan80: Vweited paraffin wax is 85:5:3:3:4; NaOH is 0.5mol/L; The pH value is 1.0; the Roi is 1:1 and Rew is 20:100. According to interfacial chemistry theory and solute diffusion theory, the mathematical model of ELM was established and validated.(2) Solvent extraction separateionThe solvent extraction system employed kerosene as solvent, TBP as extractant, CTMAB as scandium, is researched. Factors including the extractant concentration, acidity and extraction time, etc, which influenced the extraction rate of Cr(VI) were studied. Under the conditions of 40% TBP, 1.8mol/L H2SO4,0.1mol/L K2SO4,8.0 10-5mol/L CTMAB and 40min extracting, the extraction rate of Cr(VI) was 83.4%.(3) Reduction methodEffecting factors in the system used Na2SO3 as reducer, including the pH values, dosage was investigated. Experimental results showed that, when the pH value is 2.74, Cr(VI):Na2SO3 is 1:6, the remove rate of Cr(VI) in the wastewater containing 40.0mg/LCr(VI), 25.0mg/LCu(II), 15.0mg/LZn(II) and 10.0mg/LNi(II) reached 100.0%.(4) Adsorption separationIn this section, the experiments were conducted in the static and dynamic forms. The results indicated, the absorption rate of Cr(VI) in the water containing 40.0mg/L Cr(VI) was up to 92.0% after 5h, while the quality of activated carbon is 0.45g in the static experiment. And this adsorption behavior model obeyed Freundlich equation: q =55.8c0,3158; in the dynamic experiment, when the velocity of flow is ImL/min, the concentration of Cr(Vj) is 100.0mg/L, the result that penetrated time is 6h has been achieved. Applied the dynamic absorption to simulated wastewater, the absorption rate of Cr(VI) was 98.3%. The activated carbon could be regenerated by 20.0% NaOH washing, and the absorption results have no changes after repeating 3 times. At the same time, this thesis studied the absorption performance of activated carbon which its surface was modified.更多还原