改性前后活性炭处理含铬废水实验研究

发布时间：2018-04-01 19:04

  本文选题：柠檬酸　切入点：微波　出处：《西华大学》2015年硕士论文

【摘要】：工业生产中会排出大量的含铬废水,铬作为重金属类的无机有毒物质对人体的危害极大。吸附法由于其良好的处理效果而被广泛应用于处理含铬废水,随着人们对于水质的要求越来越高,废水处理领域出现了大量改性吸附材料的方法来提高吸附效率以达到更好地效果。柠檬酸改性活性炭的研究较为少见,与微波结合改性成为了含铬废水处理的新方法。本论文采用柠檬酸-微波对活性炭改性来提高其去除率,制备吸附量更大的改性活性炭,研究其制备工艺和对含铬废水的处理效果,具有重要的现实意义。本文以六价铬溶液为研究对象,采用孔隙结构发达、比表面积大、化学稳定性和热稳定性好的活性炭作为吸附材料,通过柠檬酸、微波、柠檬酸微波组合改性活性炭,分别研究了最佳的改性条件、吸附组合对吸附的影响。运用BET和SEM等研究了活性炭的微观特性。实验结果表明:(1)天然活性炭吸附六价铬最佳条件:六价铬溶液起始浓度为/20Lmg,投加量为/0.3lg,反应温度为25℃,反应pH为4,吸附时间为12h。(2)柠檬酸改性活性炭的最佳条件为柠檬酸质量浓度为50%,改性时间为4h,改性温度为30℃。改性活性炭的最佳吸附条件为室温下六价铬离子起始浓度为20mg/L,投加量为/30Lg,反应pH值为0.3,吸附时间为5h。(3)微波改性活性炭的最佳条件为C-1组合,改性时间为2min,装填量为5g。改性活性炭的最佳吸附条件是室温下六价铬离子起始浓度为/20Lmg,投加量为/10Lg,反应pH值为0.3,吸附时间为2h。(4)微波-柠檬酸改性活性炭的最佳条件为微波组合C-1,辐照1min,柠檬酸浓度50%。改性活性炭的最佳吸附条件:室温下六价铬离子溶液初始浓度为/20Lmg,吸附时间为0.1h,投加量为/10Lg。(5)四种活性炭的吸附行为过程均符合Langmuir吸附等温线模型,可用二级吸附动力学模型描述各种影响因素条件下的吸附过程。(6)GAC-N,GAC-W,GAC-NW对Cr(VI)的去除率分别为98.52%,86.25%,93.70%,较GAC-0原炭分别提高了11.86%,1.94%,6.72%。柠檬酸改性的活性炭表面的酸性官能团增加,比表面积下降。微波改性的活性炭比表面有所增大,但是表面酸性官能团大大下降,相反的碱性官能团有所提升。柠檬酸-微波改性活性炭的孔隙结构并没有破坏很大,但是其比表面积却增大很多。
[Abstract]:A large amount of chromium-containing wastewater will be discharged from industrial production, and chromium, as an inorganic toxic substance of heavy metals, will do great harm to human body. Adsorption method has been widely used in the treatment of chromium-containing wastewater because of its good treatment effect. With the increasing demand for water quality, a large number of modified adsorption materials have appeared in wastewater treatment field to improve the adsorption efficiency to achieve better results. The study of citric acid modified activated carbon is rare. In this paper, citric acid-microwave modification was used to improve the removal rate of activated carbon, and the modified activated carbon with higher adsorption capacity was prepared. It is of great practical significance to study the preparation process and the treatment effect of chromium-containing wastewater. In this paper, hexavalent chromium solution is used as the research object, the pore structure is developed, and the specific surface area is large. Activated carbon with good chemical stability and thermal stability was used as adsorption material. The optimum modification conditions were studied by combining citric acid, microwave and citric acid microwave to modify activated carbon. The effect of adsorption combination on adsorption. The microcosmic properties of activated carbon were studied by BET and SEM. The experimental results show that the optimum conditions for adsorption of hexavalent chromium from natural activated carbon are as follows: the initial concentration of hexavalent chromium solution is / / 20Lmg, the dosage is / / 0.3lg, and the reaction temperature is 25 鈩，

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