摘要
采用共沉淀法合成氢氧化镁铝溶胶MAHs,研究MAHs对模拟Cr(Ⅵ)废水的吸附行为和效果。分析溶液pH值、温度、吸附时间、MAHs投加量和Cr(Ⅵ)初始浓度等对MAHs吸附性能的影响,并采用XRD和IR表征MAHs结构,探索其吸附机理。结果表明,MAHs对Cr(Ⅵ)的适宜吸附条件为pH=6、30℃、吸附20 min,其吸附等温线符合Langmuir吸附等温方程。适宜条件下,氢氧化镁铝溶胶MAHs对Cr(Ⅵ)的饱和吸附量达90 mg/g,去除率达95%以上,对Cr(Ⅵ)具有很强的吸附能力。处理后废水达到国家规定工业废水排放标准(0.5mg/L)。氢氧化镁铝溶胶MAHs对Cr(Ⅵ)的吸附是由于铬酸根阴离子插入了MAHs样品层间,吸附剂可通过pH=2的FeCl_2溶液再生。
This paper is aimed at presenting a research on the adsorption of chromium（VI） by the magnesium aluminum hydroxides sol （MAHs） based on a series of experiments in hoping to find the best adsorption condition and the adsorption mechanism. As is well known, sol has nano-shotcrete mean particle size and high specific surface area which makes it a well material of adsorption. In our experiments, MAHs was chosen to have a few layers with cationic charges synthesized by eoprecipitation method. What we have done is to test its adsorption properties from the synthetic sewage. For the purpose to obtain desirable adsorptive characteristics, we have devised various experimental patterns and investigated the effects of the solution＇ s pH value, temperature, adsorption time, MAHs dosage and the initial chromium concentration. Furthermore, the paper has also discussed the adsorption mechanism from the change of the characteristics of MAHs by XRD and IR before and after the Cr（VI） adsorption. As the result of our experiments, the best adsorption condition has been defined as follows ： pH = 6, 30 ℃ , adsorption time 20 min. When the equation of Langmuir isotherm is used to test the process, it can be found that the linear determination coefficient is expected to reach 0.998 5 with the adsorption capacity of the MAHs rising to 90 mg/g. The data gained in our experiments suggest that more than 95 percent of Cr（VI） has been removed, thus showing the strong absorption capacity of Cr（VI） by the MAHs. After the treatment, the chromium mass concentration remains below the national standard of industrial sewage treatment （0.5 mg/L）. What is more, the X-ray diffraction patterns and the IR spectra of the MAHs before and after the adsorption of Cr（VI）, also suggest that Cr（VI） remained within the interlayer in the form of Cr2O7^2- and CrO4^2- through the adsorption process. Thus, it can be concluded that MAHs can be used for Cr（VI）-containing sewage efficiently.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2009年第2期25-28,共4页
Journal of Safety and Environment
基金
山东省自然科学基金项目(Y2007B10)
国家大学生创新性实验计划
关键词
环境工程
氢氧化镁铝溶胶
含铬废水
吸附
environmental engineering
magnesium aluminum hydroxides sol
Cr（VI）-containing wastewater
adsorption
