The Preparation, Characterization And Evaluation Of Ionic Liquids Loaded On Silica/SBA-15

In this article, eight ionic liquids-loaded on silica/SBA-15adsorbents were synthesized andcharacterized. The adsorption capacities of these adsorbents were investigated using phenolic compoundsas adsorbates. The article consisted of four parts.Chapter1, the preparation methods and application of imidazoles-loaded on silica/SBA-15adsorbentsin some areas were summarized, and it also illustrated research contents of the topic.Chapter2,1-allyl-3-butylimidazolium ionic liquid-loaded on silica adsorbent SiVBIm1Br wassynthesized via chemical bonding, SiVBIm1BF4and SiVBIm1PF6were obtained by anion exchange.Similarly, Adsorbents SBA-15609VBIm1Br and SBA-15XprIm2Cl (X=650,992) were synthesized by1,4-Bis(Imidazol-1-yl)butane loading on SBA-15with different BET surface areas. Further,SBA-15992prIm2C4Cl and SBA-15992prIm2C8Cl were obtained by extending the length of alkyl chain. Alladsorbents were characterized by scanning electron microscope, transmission electron microscope, infraredspectra, thermogravimetric analysis, elemental analysis, BET analysis, HNMR, and X-ray diffraction,which indicated the validity of preparation methods and operation.Chapter3, SiVBIm1Br, SiVBIm1BF4and SiVBIm1PF6as adsorbents were used to remove2,4-dinitrophenol (2,4-DNP),2,4-dichlorophenol (2,4-DCP) and3-nitrophenol (3-NP) in aqueous solutionand the effects of physico-chemical parameters such as initial concentrations, adsorbent dosage,temperature, contact time and solution pH were investigated, the adsorption isotherm and kinetic equationwere also investigated by initial concentrations and contact time at different temperature respectively.Further, the adsorption-desorption process of SiVBIm1Br, SiVBIm1BF4and SiVBIm1PF6for2,4-DNP were inspected. In the static adsorption experiments it was found that the adsorption capacities followed theorder of SiVBIm1Br> SiVBIm1BF4> SiVBIm1PF6and they were optimal using original solution pH andthe rate of sorption was very fast during the first5min except2,4-DCP. The adsorption processes (exceptSiVBIm1PF6adsorbed2,4-DNP) were in accord with Freundlich adsorption isotherm, while the process ofSiVBIm1PF6adsorbing2,4-DNP could be described by Freundlich and Langmuir adsorption isotherm. Indynamics experiments of SiVBIm1BF4, secondary kinetic equation could describe the adsorption processbetter, whose correlation coefficient≥0.9990. In the adsorption-desorption experiments, the HCl of aspecific concentration could elute2,4-DNP drastically. And the SPE column had a high repeatability of atleast11times.Chapter4, SBA-15609VBIm1Br, SBA-15650prIm2Cl, SBA-15992prIm2Cl, SBA-15992prIm2C4Cl andSBA-15992prIm2C8Cl as adsorbents were used to remove2,4-DNP in aqueous solution and the effects ofphysico-chemical parameters such as initial concentrations, adsorbent dosage, temperature, contact time,solution pH and inorganic anions were investigated, the kinetic equation were investigated by effects ofcontact time at different temperature further. The results in the static adsorption experiments showed thatthe adsorption capacities followed the order of SBA-15992prIm2Cl <SBA-15609VBIm1Br <SBA-15650prIm2Cl <SBA-15992prIm2C4Cl <SBA-15992prIm2C8Cl and the rate of sorption was very fastduring the first5min (adsorption capacity was35-60mg/g at5min). SBA-15650prIm2Cl,SBA-15992prIm2C4Cl and SBA-15992prIm2C8Cl presented higher adsorption capacities than otheradsorbents between15-50oC, which indicated they had a good adaptation and high temperature couldspeed up the adsorption process of SBA-15992prIm2C4Cl. Further, the adsorption processes (exceptSBA-15609VBIm1Br and SBA-15650prIm2Cl adsorbed2,4-DNP) were in accord with Freundlich adsorptionisotherm, while the processes of the two adsorbents adsorbing2,4-DNP could be described by Freundlich and Langmuir adsorption isotherm. In dynamics experiments, secondary kinetic equation could describe theadsorption process better.