Development of Room-Temperature Synthesis Method of Mesoporous Silicates and Their Application to Catalysts and Adsorbents

本文对各种介孔硅酸盐金属的合成及其在催化剂和吸附剂中的应用进行了研究，总结了一些重要的研究结果。作为一种方便和低成本的表面活性剂介导的方法，我们开发了一种快速室温（RRT）工艺，从阳离子表面活性剂和无机硅源（如硅酸钠）的水溶液（0<pH<11）中在几小时内得到六方介孔二氧化硅（MPS）。通过简单改性，用RRT法成功合成了铝硅酸盐（MPAS）、硅铁硅酸盐（MPFS）和硅酸钛（MPTS）等介孔金属硅酸盐（mpms）。合成溶液的pH值和荷电Si/M比决定了MPMSs的结构性能。MPAS在6<pH<11和Si/Al >0条件下，MPFS在8<pH<12和Si/Fe bbb30条件下，MPTS.2在pH<1和Si/Ti >0条件下成功合成了高质量的MPMSs。研究了SnO_2、ZrO_2或TiO_2对MPS的改性，采用重复后接枝法，即表面羟基化、表面羟基接枝金属氯化物或烷氧化物以及在空气中煅烧的循环。所得的SnO_2-和zro_2 -包覆的MPS与宿主MPS相比，对高温（bb0 ~ 800℃）和NaOH水溶液（<70℃）具有较好的耐蚀性。MPASs具有离子交换性能，通过离子交换法引入的Cu离子被H_2还原为Cu^<2+>→Cu^+→Cu^0。Cu^+-MPAS由Cu^<2+>-MPAS部分还原得到，具有较高的抗氧化性和CO/CO_2选择性，是一种优良的CO吸附剂。研究了MPS和MPMSs作为吸附剂和光催化剂在光照和不光照条件下对亚甲基蓝（MB）的漂白作用。在MPS的硅酸盐骨架中引入Al和Fe，可以有效地增强对MB（暗反应）的吸附。光照条件下，MPFS和MPTS均表现出MB的光催化分解活性，MPFS的光催化活性高于MPTS。除上述研究外，还研究了MPS和MPMSs对SO_2的吸附性能，海藻酸辅助制备含介孔材料的吸附剂珠等。少

Synthesis and Application to catalysts and adsorbents of various mesoporous metallosilicates have been investigated, and some important results are summarized below.1. As a convenient and low-cost surfactant-mediated method, we developed a rapid room temperature (RRT) process, which gave hexagonal mesoporous silica (MPS) in a few hours from aqueous solutions (0<pH<11) of cationic surfactants and inorganic Si sources like sodium silicate. By the simple modification, mesoporous metallosilicates (MPMSs) such as aluminosilicate (MPAS), ferrosilicats (MPFS) and titanosilicate (MPTS) were successfully synthesized by the RRT method. The structural properties of MPMSs were dependent on the pH and the charged Si/M ratio of synthetic solutions. High quality MPMSs were successfully synthesized at 6<pH<11 and Si/Al>20 for MPAS, at 8<pH<12 and Si/Fe>30 for MPFS, and at pH<1 and Si/Ti>10 for MPTS.2. Modification of MPS with SnO_2, ZrO_2 or TiO_2 was investigated by the repeated post-grafting method, … More which consisted of the repetition of the cycle of hydroxylation of the surface, grafting of metal chloride or alkoxides through the reaction with surface hydroxyl groups and calcination in air. The resulting SnO_2- and ZrO_2-coated MPSs were quite resistant, as compared with the host MPS, against treatments at high temperature (>800 ℃) and aqueous NaOH (<70 ℃).3. MPASs showed the ion-exchange property and Cu ions introduced in MPASs by the ion-exchange method were reduced by H_2 in two steps, Cu^<2+> → Cu^+→ Cu^0. Cu^+-MPAS, which was obtained by the partial reduction of Cu^<2+>-MPAS, was found to be an excellent adsorbent for CO with high oxidation-resistance and CO/CO_2 selectivity.4. MPS and MPMSs were investigated as adsorbents and photo-catalysts for bleaching of aqueous methylene blue (MB) with or without photo-illumination. The introduction of Al and Fe in the silicate framework of MPS was effective in enhancing the adsorption of MB (dark reaction). Under illumination, MPFS and MPTS showed photocatalytic decomposition activity of MB and MPFS was more photocatalytically active than MPTS.5. In addition to the above-mentioned researches, also investigated were SO_2 adsorption property of MPS and MPMSs, alginic acid-aided preparation of adsorbent beads containing mesoporous materials, and so on. Less