Study On Recovery Of Organic Template From Porous Materials

Porous materials with regular pore structure, large surface area, highhydrothermal stability and modified surface have wide range potentialapplications in petroleum catalysts, adsorbents and variety of new materials. Itneeds numerous organic template in the process of synthesis porous materialsfor forming the functional and structural unity pore. These organic templateshould be removed to prepare with regular open porous structure materialsbefore applying as petroleum catalysis, exhaust gas adsorption and ionexchange. Template can completely be removed by calcination, but thismethod has some drawbacks following as: it does not allow the recovery ofexpensive template and noxious gases emitted during the calcination processto lead to environmental pollution. In addition, it is a time-consuming process,which requires at least10h for completion. What is more, it causes structureshrinkage or collapse when the inorganic framework is temperature sensitive.Thus, it is necessary to explore alternative methods for the template removal.The optimum conditions to recover organic template P123（EO₂0PO₇0EO₂0） from SBA-15were studied by using three different methods:supercritical CO₂extraction, solvent extraction and ultrasonic extraction. Theextracted SBA-15were characterized by X-ray diffraction, TGA analysis,Fourier infrared spectroscopy and N2adsorption-desorption isotherms. Theobtained SBA-15maintained highly ordered framework and higher surfacearea than those of calcined samples. The recovery process of three methodscan avoid the structure shrinkage and silanol group removal caused by highthermal calcination. The recovered P123was characterized by Fouriertransform infrared spectroscopy （FT-IR） and gel permeation chromatography（GPC）, and was identified the same as the reference P123, which may bereused in future material synthesis.On the basis of above experiment, supercritical CO₂extraction SBA-15molecular sieve models are studied in this paper. Through the Naik model andthe hot ball model, the calculated and experimental values agreed very well,AARD of which was5.66%and2.37%, respectively. The two models canprovide a theoretical basis for the industrialization of supercritical CO₂extraction porous materials.