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

本文对各种介孔金属硅酸盐的合成及其在催化剂和吸附剂中的应用进行了研究，主要结果如下：1.作为一种方便、低成本的表面活性剂介导法，我们开发了一种快速室温（RRT）方法，该方法在几个小时内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）中得到六方介孔二氧化硅（MPS）。通过简单的改性，用RRT法成功地合成了硅铝酸盐（MPAS）、硅铁酸盐（MPFS）和钛硅酸盐（MPTS）等介孔金属硅酸盐（MPMS）。MPMS的结构性质依赖于合成溶液的pH和带电Si/M比。在pH<11，Si/Al>20的条件下，制备了高质量的MPMS;在pH<12，Si/Fe>30的条件下，制备了高质量的MPFS;在pH<1，Si/Ti>10的条件下，制备了高质量的MPTS.采用多次后接枝法研究了SnO_2、ZrO_2、TiO_2对MPS的改性， 关于我们 其包括重复表面羟基化、通过与表面羟基反应接枝金属氯化物或醇盐以及在空气中煅烧的循环。与基体MPS相比，SnO_2和ZrO_2包覆的MPS对高温（>800 ℃）和氢氧化钠水溶液（<70 ℃）的耐受性较好. MPAS具有离子交换性质，通过离子交换法引入的Cu离子被H_2还原，还原过程分为两步：Cu^<2+> → Cu^+→ Cu^0。由Cu^<2+>-MPAS部分还原得到的Cu^+-MPAS具有良好的抗氧化性和CO/CO_2选择性，是一种优良的CO吸附剂.研究了多磺酸粘多糖（MPS）和多磺酸粘多糖（MPMS）作为吸附剂和光催化剂对亚甲基蓝（MB）水溶液的光催化漂白作用。在MPS的硅酸盐骨架中引入Al和Fe可以有效地增强对MB的吸附（暗反应）。在光照条件下，MPFS和MPTS均表现出光催化降解MB的活性，且MPFS的光催化活性高于MPTS.除上述研究外，还研究了多相和多相介孔分子筛对SO_2的吸附性能，海藻酸辅助制备含介孔材料的吸附剂小球等。

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