| 硅气凝胶常压制备、表征及对狄氏剂吸附性能研究 |
| 摘要点击 3488 全文点击 2238 投稿时间：2008-01-29 修订日期：2008-03-10 |
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| 中文关键词 硅气凝胶 常压干燥 吸附 狄氏剂 吸附动力学模型 |
| 英文关键词 silica aerogel ambient drying adsorption dieldrin adsorption kinetics |
| DOI 10.13227/j.hjkx.20081221 |
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| 中文摘要 |
| 以工业水玻璃为硅源，采用三甲基氯硅烷［(CH3)3SiCl，TMCS］/乙醇［CH3CH2OH，EtOH］/正己烷［C6H14］混合液对硅水凝胶进行溶剂交换和表面改性，在常压干燥条件下获得疏水硅气凝胶材料，并对其吸附狄氏剂性能进行了系统评价.BET、FTIR、热重等表征结果显示，制得的硅气凝胶材料接触角在135°～142°之间，比表面积在444～560 m2·g-1之间，孔径范围为17.5～23.4 nm，孔隙率为94.8%～95.6%，材料在空气中的耐热温度约为380℃.改性剂用量与组成比例对材料性能有较大影响，在TMCS∶EtOH∶C6H14摩尔比为1∶1∶1时，材料疏水性、比表面积和孔容孔径等物理化学性质达到最大值.本方法制备的疏水硅气凝胶对狄氏剂表现出良好的吸附性能，4 h内狄氏剂去除率达到84%；吸附动力学符合准二级动力学模型，吸附速率常数随疏水性增强而增大；Freundlich系数Kf为30.22 μg·g-1，是活性炭的11倍. |
| 英文摘要 |
| Hydrophobic silica aerogels were prepared from cheap waterglass precursors via surface modification of wet gels and ambient pressure drying route. Its adsorption capacity of Dieldrin, a typical of persistent organic pollutants (POPs), was examined. It is characterized via BET, FTIR, and DSC-TGA. The silica aerogels were highly hydrophobic with contact angles of 135°-142°, and the hydrophobicity of the aerogels could be maintained up to the temperature of 380℃. The silica aerogels were porous with, pore size distribution of 17.5-23.4 nm, porosity of 94.8%-95.6%, and surface area of 444-560 m2·g-1. The results of adsorption experiments indicated that the hydrophobic aerogels could remove 84% of dieldrin from aqueous solution within 4 h; the adsorption process followed the pseudo-second-order kinetics process. Based on the adsorption equilibrium results, the adsorption capacity of silica aerogel was 11 times bigger than by active carbon. |
