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蒙脱石有机插层复合物的制备及其对含Cr(Ⅵ)废水吸附行为的研究

Preparation of Organic-intercalation Montmorillonite Composites and Their Adsorption Behavior in Wastewater Containing Cr(Ⅵ) Ions

【作者】 付桂珍

【导师】 龚文琪;

【作者基本信息】 武汉理工大学 , 环境工程, 2003, 硕士

【摘要】 为了拓展非金属矿物在环境保护中的应用,我们开展了本课题的研究,国内外对蒙脱石层间化合物在废水处理领域的应用开展了一些研究,但多集中于蒙脱石有机层间化合物对废水中有机污染物和重金属阳离子的吸附去除方面,对于蒙脱石有机层间化合物吸附Cr(Ⅵ)有害阴离子基团的研究则未见报道。本论文以辽宁某地蒙脱石为原料,系统研究了蒙脱石有机插层复合物的制备及其对废水中Cr(Ⅵ)有害阴离子(CrO42-、Cr2O72-等)的吸附行为与机理。 实验制备了十六烷基三甲基溴化铵/蒙脱石有机插层复合物,实验结果表明,插层剂的加入量影响蒙脱石有机插层复合物的晶层间距,制备蒙脱石有机插层复合物的最佳插层剂加入量为120%CEC,此时制备的钙基蒙脱石有机插层复合物(GY)的晶层间距由钙基蒙脱石(原土)的15.5589(?)提高到18.1821(?),钠基蒙脱石有机插层复合物(NY)的晶层间距由钠基土(钠化土)的12.9605(?)提高到20.4536(?)。 实验研究了蒙脱石有机插层复合物对废水中Cr(Ⅵ)的吸附行为。结果表明:有机改性后的蒙脱石NY和GY对Cr6+的吸附效果明显高于原土和钠化土,其吸附去除率随改性时插层剂加入量的增大而增大,当超过100%CEC后则对低浓度Cr(Ⅵ)废水的吸附去除率不再随插层剂加入量的增大而增大。吸附去除率受pH值、反应时间、吸附剂投加量和废水初始浓度等因素影响。蒙脱石有机插层复合物吸附的最佳pH值为3,吸附平衡时间为60min,吸附去除率随吸附剂投加量的增加而增加、随初始浓度的增加而降低。在最佳实验条件下即pH值为3,吸附反应时间为60min,吸附剂NY和GY投加量为2g/100mL时NY和GY对4mg/L含Cr6+废水吸附去除率分别达98%和69%。经NY吸附处理初始浓度为4mg/L的含Cr6+废水,其残留浓度达到国家规定的排放标准(0.5mg/L)。 论文采用SEM、XRD、FTIR和DTA/TG等先进测试技术对所研制的蒙脱石有机插层复合物进行了表征,并研究其对Cr(Ⅵ)的吸附机理。研究表明,Cr(Ⅵ)在水中主要以CrO42-、Cr2O72-等阴离子基团存在,很难进入层间,因此原土和钠化土的吸附效果不佳。而十六烷基三甲基溴化铵插层剂不仅通过阳离子交换,而且通过疏水键吸引作用进入层间,插入量超过100%CEC,使层间距显著提高,吸附效果明显改善,因此能有效去除废水中的Cr(Ⅵ)阴离子。 论文所取得的成果只有创新性,为有效去除废水中的Cr(Ⅵ)提供了一种高效价廉的水处理剂,同时也为有机膨润土开辟了新的应用领域,具有理论意义与应用前景。

【Abstract】 This subject is launched to enlarge the appliance of nonmetallic minerals in environmental protection. Up to now, the study of appliance of intercalated montmorillonite in waste water treatment is mostly about the adsorption of organic pollutants on organic-intercalation montmorillonite composites. Little study is done about the adsorption of inorganic pollutants and especially hazardous Cr(VI). In this thesis , The preparation of organic-compound-intercalated montmorillonite and it’s adsorption behavior mechanism of Cr(VI) in waste water are investigated.Organic-compound-intercalated montmorillonite is prepared. The results show that the amount of the intercalated agent affects the interplanar spacing of organic-compound-intercalated montmorillonite and the adsorption effects of Cr(VI) on organic-compound-intercalated montmorillonite ,which are obviously higher than that of original montmorillonite or sodium montmorillonite. The optimum amount of the intercalated agent is 120%CEC. The interplanar spacing of organic-compound-intercalated montmorillonite(NY and GY) is respectively 20.4536A and 18.1821A when the amount of the intercalated agent is 120%CEC.Adsorption rate of Cr( VI) on organic-compound-intercalated montmorillonite is investigated. The results show that the adsorption rate is affected by pFU reacting time, inventory of adsorbents and original consistency of waste water. The optimum PH is 3, adsorption equilibrium time of is 60 min , The adsorption rate of Cr(VI) is increased when the inventory of adsorbent is increased and reduced when original consistency of waste water is increased.The adsorption rate of Cr(VI) on organic-compound-intercalated montmorillonite (NY and GY) in 4mg/L Cr(VI) waste water is up to 98% and 69% when the inventory of adsorbents is 2g/100mL.

  • 【分类号】X703.5
  • 【被引频次】1
  • 【下载频次】406
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