不同溶剂萃取回收SBA-15中有机模板剂的研究

Recovery of the organic template from SBA-15 using solvent extraction

利用3种不同的溶剂对SBA-15分子筛中有机模板剂P123(EO20PO70EO20)的最佳萃取工艺条件进行了研究,考察了溶剂种类、萃取温度、萃取时间、溶剂量对回收率的影响。实验确定的最佳萃取工艺条件为甲醇作为溶剂,萃取温度75℃,萃取时间3.5h,溶剂量300mL,在此条件下P123回收率可达80.7%。制备得到的SBA-15分子筛通过X射线衍射、热重分析、Fourier红外光谱及N2吸附脱附等手段进行表征,结果表明通过溶剂萃取得到的SBA-15骨架有序性保持良好,比表面积更大。溶剂萃取过程不会造成骨架硅羟基脱除,克服了高温焙烧所引起的孔道收缩问题。回收得到的模板剂P123通过液体红外光谱和凝胶渗透色谱等手段进行表征,表明其在宏观和微观方面具有与标准样品相同的性质。

The organic template P123 （EO20PO70EO20） has been recovered from. SBA-15 molecular sieves using solvent extraction with three different solvents. The effects of extraction solvent type, extraction temperature, ex- traction time and extraction solvent dose on the recovery ratio were studied. The results showed that under the opti- mal operating conditions with methanol as solvent, extraction temperature of 75 ℃, extraction time of 3.5 h, and extraction solvent dose of 300 mL, the template P123 recovery ratio was 80.7%. The extracted SBA-15 was charac- terized by X-ray diffraction （XRD）, thermogravimetric analysis （TGA）, Fourier transform infrared spectroscopy （FT-IR） and N2 adsorption-desorption isotherms. The recovered SBA-15 had a more ordered framework and a higher surface area than samples from which the template had been removed by calcination, showing that template recovery by solvent extraction can avoid the structure shrinkage and silanol group removal caused by high tempera- ture calcination. The recovered P123 was characterized by Fourier transform infrared spectroscopy （FT-IR） and gel permeation chromatography （GPC） , and was identical to the reference P123 sample.