水分子凝聚体系的介孔结构分形学

透射电镜研究表明，4,40-双硬脂酰胺基二苯醚在水中聚集、自组装成缠绕细纤维状聚集体，进而使整个体系形成三维网络结构．水分子被包囊在这个网络结构中，形成一种新型的凝聚体系(水分子凝胶)．水分子凝胶是一种典型的纳米介孔物质，其复杂的微孔结构可以用分形维数D来表征，通过气体吸附方法(孔度法和比表面积法)计算，求得水分子凝胶体系的微孔结构的分形维数为2.1?2.2．对于纤维状三维网络结构的分形表征，通过粘度法和Cayley分形树模型得出分形维数为1.98．由此推测其分形网络形成的过程是一个初始成核-生长-枝化的循环过程．     

Kinetics and equilibrium of adsorption of organic solutes on mesoporous carbons

Static and kinetic studies on adsorption of nitrobenzene, 4-nitrophenol and 4-chlorophenol on two mesoporous carbons are performed. The carbon properties are analyzed by means of nitrogen adsorption. The adsorption experiments are performed in acidic buffer solutions in a wide range of concentrations. The static experiments are analyzed by means of Langmuir-Freundlich and Freundlich isotherms. The Lagergren, pseudo-second-order, intraparticle-diffusion and multi-exponent equations are used in the analysis of kinetic equilibria.     

Surface status and size influences of nickel nanoparticles on sulfur compound adsorption

Metallic nickel nanoparticles were incorporated on mesoporous silica to remove sulfur compounds in diesel selectively. In the first method, nickel nanoparticles were formed on mesoporous silica SBA-15 by impregnation and subsequent reduction of nickel nitrate. The sulfur adsorption capacity was strongly dependent on the nickel loading and the average nickel particle size. In the second method, nickel nanoparticles were synthesized in solution in the presence of a capping agent and then incorporated in mesoporous silica MCF by sonication. Although these particles maintain their sizes on the MCF surface after heat treatment, capping agent remaining on the Ni particle surface might interfere the adsorption of sulfur compounds.     

Study on the effect of different acids on the structure and photocatalytic activity of mesoporous titania

Nanocrystalline mesoporous titania was synthesized via a combined sol–gel process with surfactant-assisted templating method using cetyltrimethyl ammonium bromide (CTAB) as the structure-directing agent. The process was catalyzed by different acid (hydrochloric acid, nitric acid, sulfuric acid, or phosphoric acid). The prepared samples were characterized by XRD, TEM, BET and FT-IR. The photocatalytic activity of the samples was determined by degradation of phenol in aqueous solution. Results showed that different acid had different effect on the structure and crystal phase of the samples. The sample adjusted by phosphoric acid showed highest surface area and photocatalytic activity. The formation mechanism of the samples catalyzed by different acid was also discussed.     

Simultaneous determination of nitroaromatic compounds in water using capillary electrophoresis with amperometric detection on an electrode modified with a mesoporous nano‐structured carbon material

In this article, a carbon disk electrode modified with mesoporous carbon material (CMK‐3) was used in CE with amperometric detection system for the simultaneous determination of four types of important nitroaromatic compounds, including 2,4,6‐trinitrotoluene (TNT), 1,3,5‐trinitrobenzene (TNB), 2,4‐dinitrotoluene (DNT) and 1,3‐dinitrobenzene (DNB). Compared with the bare carbon electrode, the CMK‐3 modified electrode greatly improved the sensitivity at a relatively positive detection potential due to its excellent electrocatalytic activities, high conductivity and large effective surface area. The four analytes could be well separated and detected within 480 s. A good linear response was obtained for TNB, DNB, TNT and DNT from 8.4 to 5.0×10³ μg/L, with correlation coefficients higher than 0.9992. And the detection limits were established between 3.0 and 4.7 μg/L for the four investigated nitroaromatic compounds (S/N=3). The CMK‐3‐modified electrode was successfully employed to analyze coking wastewater, tap water and river samples with recoveries in the range of 94.8–109.0%, and RSDs less than 5.0%. The presented results demonstrated that the CMK‐3‐modified carbon electrode used in CE with amperometric detection was of convenient preparation, high sensitivity and good repeatability, which could be employed in the rapid determination of practical samples.     

Towards Realization of a Micro- and Mesoporous Composite Silicate Catalyst

A composite silicate material, which possesses the characteristics of both microporous zeolite and mesoporous silica materials, is developed by top–down and bottom–up synthesis techniques. In order to realize a micro- and mesoporous composite material, several essential points must be clarified, since each porous material is synthesized under very different metastable conditions: zeolite is a silicate crystal, while the wall of mesoporous material is composed of amorphous silicate. Here, some aspects of the realization of a micro- and mesocomposite porous material are described, as are our experimental results regarding the successful production of composite catalyst.     

Periodic Mesoporous Silicas and Organosilicas: An Overview Towards Catalysis

Micelle-templated mesoporous and organic–inorganic hybrid mesoporous materials are important in many fields of material research, especially for hosting catalysts in confined space. Among this class, the recent discovery of periodic mesoporous organosilicas (PMOs) represent an exciting new group of organic–inorganic nanocomposites targeted for a broad range of applications ranging from catalysis to microelectronics. Compared to the earlier generation of organic–inorganic hybrid mesoporous samples, obtained by the cocondensation reaction or by the grafting reaction, PMOs represent the right combination of organic and inorganic groups in the frame wall positions. This article reviews the current state of art in organic–inorganic hybrid mesoporous material research with special emphasis over periodic mesoporous organosilica materials having various redox centers (Ti, V, Cr) suitable for oxidation reactions as well as acidic sites (Al, –SO₃H) for the organic transformation of bulky molecules.     

Mesoporous aluminosilicate nanocage-catalyzed three-component coupling reaction: an expedient synthesis of α-aminophosphonates

Here we demonstrate for the first time the synthesis of α-aminophosphonates through the three-component coupling reaction of aldehydes, amines, and diethyl phosphite by using highly acidic 3D mesoporous aluminosilicate nanocage catalyst, which gave excellent yield with a high selectivity in a short reaction time due to its high acidity, 3D pores, and a huge space in the nanocages.     

高效固体酸SBA-15-Zr(OTf)3催化胺或醇开环环氧化合物

通过简单的一锅两步法制备了三氟金属(铝,钛,锆)接枝介孔SBA-15 (AlTf/S,TiTf/S,ZrTf/S)固体酸材料,并通过XRD,N2吸附,TGA,FTIR,原位吡啶FTIR和元素分析对这些材料进行了详细的表征.其中,ZrTf/S能够高效催化环氧化物温和条件下被胺或醇开环生成对应β-氨基醇或β-烷氧基醇,并且催化剂能循环利用.ZrTf/S相较于AlTf/S和TiTf/S酸性最强,因而催化活性也最高.     

中孔分子筛P1 23-SH分离富集-火焰原子吸收光谱法测定礼花弹中银

制备了中孔分子筛P123-SH,并对其用于吸附银离子的条件进行了探索。试验发现在温度为(20±1)℃,介质pH值为3.6时,振荡吸附10 min,吸附容量为15.97 mg·g~(-1),吸附率可达98.5%。吸附在中孔分子筛P123-SH上的银离子可用0.2 mol·L~(-1)盐酸-0.1 mol·L~(-1)硫脲溶液5 mL完全洗脱回收,用火焰原子吸收光谱法测定洗脱液中痕量银的含量。银的质量浓度在0.008～0.24 mg·L~(-1)范围内与其吸光度呈线性关系,方法的检出限(3σ)为0.64μg·L~(-1)。方法用于礼花弹样品中银含量的测定,加标回收率在97.5%～115.0%之间,相对标准偏差(n=7)为2.4%。