| Persistent organic pollutants in the industrial waste gases generally have larger sterichindrance. Therefore, the adsorption materials or catalyst carrier with larger aperture andhigher specific surface area (BET) are needed to get rid of the persistent organic pollutantswhen using adsorption and catalytic combustion method. In addition, mesoporous materials,used as adsorption material and catalyst carrier, have limited application in the air pollutionpurification fields due to their poor hydrophobic property and poor thermostability. The studyaims at the two issues.This paper presents a hydrothermal method to synthesize two mesoporous materials ofDFS and MFS by using perfluorinated short chains of SORFLON S-386as second and theonly template. The paper also illustrates how the process conditions impact on the synthesizedresults when DFS and MFS are synthesized under the low temperature (<423K) condition.Many methods such as FTIR, XPS, nitrogen adsorption, TEM, SEM, small Angle XRD, PY-GC/MS and29Si-NMR have been used to characterize DFS and MFS. The experimentalresults are as follows:The optimal reaction conditions for DFS synthesis are: pH=1, reaction materials ratioMSURFLON S-386: MTEOS=8%(m/m), MP123: MTEOS=10%(m/m), and the crystallizationtemperature is368K, the crystallization time is50h, the calcination teperature is823K, andthe content of NaCl are0.5g. The biggest Specific surface area (BET) of DFS is724m2g-1,while the average pore diameter (BJH) and the adsorption entrance (BJH) are4.7nm and0.65cm3g-1, respectively. The small angle XRD and TEM show that the prepared DFS sample haswell-ordered structure.The optimal reaction conditions for MFS synthesis are: pH=1, reaction materials ratio,MSURFLON S-386: MTEOS=10%(m/m), and the crystallization temperature is373K, thecrystallization time is50h, the calcination teperature is843K, and the content of NaCl are0.5g. The biggest Specific surface area (BET) of MFS is865m2g-1, the Langmuir specificsurface area is1205.1m2g-1； while the average pore diameter (BJH) and the adsorptionentrance (BJH) are4.9nm and0.74cm3g-1, respectively. The small angle XRD and TEMshow that the prepared MFS sample has some-ordered structure.Different characterization techniques show many fluoride groups are on the surface ofDFS and MFS, and these fluoride groups come from the residuals of the calcinated templateSURFLON S-386. The residual fluoride groups ratio on the surface of DFS and MFS aredetermined by the synthetic process conditions, and the content of residual fluoride groups is stable.This paper studies the adsorption performance of water vapor on MFS, DFS, MCM-41and SBA-15under different temperatres (283,293,303and313K). The results show thatwater adsorption isotherm for different materials are basically consistent with the typeⅤsorption isotherm and the adsorption processes are all physical adsorption. This paper alsoestimates the isosteric adsorption heat, adsorption activation energy and desorption activationenergy of different materials.This paper researches on the catalytic combustion processes of naphthalene with MFS,DFS, SBA–15, MCM-41and ZSM-5as the carriers of the copper base catalysts. The resultsshow that the naphthalene conversion rate curve has kept rising slowly in the temperaturerange of373~873K when using different concentrations of CuO-MFS and CuO-DFS ascatalysts. It indicats that CuO-MFS and CuO-DFS catalysts have good stability at hightemperature. However, the naphthalene conversion curves show uprising first and thendescending when MCM-41, SBA-15and ZSM–5are used as catalyst carriers in catalyticcombustion of naphthalene, which means that these materials have poor stability under thecondition of high temperature and water vapor.This paper investigates the hydrophobic performance (HP) of different materials and theresults from different synthesis methods show that the HPs of catalysts decrease in thefollowing order: HPMFS＞HPDFS＞HPSBA-15＞HPMCM-41；... |
PDF Full Text Request