| Hydrotalcite laminate contains a lot of active hydroxyl groups, such that the adjacent particles are bonded together by hydrogen bonds during the drying process, leading to the uneven particle size, poor dispersion and so on. According to the shortcomings of hydrotalcite, the hydrotalcite was modified by anionic, nonionic surfactants and anionic-nonionic surfactant in this project. Inverse gas chromatography(IGC) was used to investigate the surface properties of modified hydrotalcites, studying the stability effect of hydrotalcite modified by anionic-nonionic surfactant, and the modification effect of different nonionic surfactant was studied. In addition, hydrotalcite-derived mixed metal oxides(LDO) have good adsorption effect due to the high specific surface area and the special structure of pore. In this paper, using the IGC to explore the effect of different trivalent metal ions on the absorption capacity, developing the application field of LDO finally.The main studies and results of this dissertation are as follows:(1) The surface modification of magnesium-aluminum hydrotalcite by sodium dodecyl benzene sulfonate(SDBS), Tween-80 and anionic-nonionic surfactant were carried out. The crystal type and structure of samples were characterized by means of XRD, FTIR. Inverse gas chromatography(IGC) was used to estimate the surface free energy(ΔG0) and the dispersive component of the surface energy(γsd), exploring the surface properties of hydrotalcite and modified hydrotalcites. Meanwhile the modification mechanism of hydrotalcite by anionic-nonionic surfactant was proposed. The results show that the chemical stability of modified hydrotalcite become better than hydrotalcite, and the chemical stability of SDBS/Tween-LDHs become better than other modified LDHs.(2) The magnesium-iron hydrotalcite was modified by three nonionic surfactants(Span-20, Tween-80, Triton X-100) combined with sodium dodecyl benzene sulfonate(SDBS), respectively, and free energy of adsorption(-ΔG0), dispersive component of the surface energy(γsd) and acid-basic action free energy(-ΔGsp) were investigated using inverse gas chromatography(IGC), studying the effect of different nonionic surfactant on modification. The results show that the the alkalinity of modifed hydrotalcites is weakened, the alkalinity of SDBS/Triton-LDHs is the weakest, and SDBS/Triton-LDHs has the best stability.(3) Zn-based layered double hydroxides were synthesized by coprecipitation. Inverse gas chromatography(IGC) was applied to characterize the surface properties of mixed metal oxides [Zn3M-LDO(M=Cr, Al, Fe)] which were calcined hydrotalcites at 500 ℃. The free energy of adsorption(-ΔG0), dispersive component of the surface energy(γsd) and acid-basic properties of mixed metal oxides were estimated by using the different non-polar and polar probes. The results show that the adsorption capacity of Zn3Fe-LDO is the strongest among these mixed metal oxides. In addition, the surface of mixed metal oxides has the acid site and the basic site, the LDO is amphoteric and predominantly acid material. The LDO is beneficial to adsorb alkaline materials, developing the application field of LDO finally. |
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