Preparation Of Saponite And Layer-by-layer Assembly Composites

Saponite and hydrotalcite are two kinds of ionic materials having practical application value among the numerous layered materials. As a member of layered silicate, saponite has great potential in nanocomposite, medicine, sensor and catalyst synthesis. The latter having the large anion exchange capacity has been applied in catalysis and pharmacy fields. HTc, the calcined form of hydrotalcite、has larger adsorption capacity for anion than hydrotalcitc.Smectite family is an aluminosilicate mineral, which belongs to a part of cationic layered clay. Smectite is easy to be dispersed and swelling in water, its interlayer cation is also exchangeable. Based on the high stability and large surface area, smectite is widely used in various industrial sectors. However, the composition of natural smectite clay is very complex, mainly because the replacement of central metal ions occurring in the tetrahedral or octahedral laminates, which makes the structure more complex. Natural clay contains impurities, separation and purification is very difficult. In practical industrial applications, small quartz particles seriously impede the application of the clay minerals. In short, the structure and composition of the natural clay result in he differences of the surface nature and the difficulties of practical application. However, synthetic clay can avoid the application of natural clay to a great extent. Therefore, research on synthetic smectite family of clay has great practical significance.Compared to the smectite family of cationic clay minerals, Hydrotalcite is a kind of anionic layered clay and has very broad application. Hydrotalcite laminates on hydroxyl octahedral cations and interlayer anions with adjustable degeneration, the pH of the Hydrotalcite can largely be changed thereby affecting its catalytic properties. However, the specific surface area of naturally occurring or synthetic Hydrotalcite is smaller, which results in the utilization of active center in the catalytic reaction. Therefore, the use of Hydrotalcite-like laminates and the smectite laminates with charge opposite and ions in the interlayer exchangeable, Hydrotalcite laminates and smectite laminates, intercalation synthetic assembly of interactive laminated composite The material has great significance. Main contents and conclusions are as follows:This article selects copper nitrate, nickel nitrate and sodium silicate as raw materials, the hydrothermal synthesis method for synthesis of a copper saponite and nickel saponite, with the means of XRD, TG-DTA, FT-IR, SEM and N2-adsorption desorption The synthesis products were characterized by physical and chemical properties, and influences of the concentration of reactants ratio, crystallization temperature, crystallization time on the synthesis of smectite structure. The results showed that:Synthesis of saponite, copper and nickel saponite reactants stoichiometric ratio of natural smectite; crystallization temperature and crystallization time on the compounds phase crystallization of impact, but the synthesized product The skeleton structure has little effect; synthetic saponite N2-adsorption and desorption analysis showed that the crystallization temperature and crystallization time on the product of the pore structure and pore size have a significant impact.Preparation of Ni-Al Hydrotalcite/saponite layered composites of nickel nitrate, aluminum nitrate, sodium hydroxide, sodium silicate as raw materials. Ni-Al Hydrotalcite-like prepared by coprecipitation were dispersed in N, N-dimethyl formamide solution sonication48h, and then the synthetic saponite precursor slurry mixed at room temperature under stirring24h. With XRD, DTA, the FT-IR, particle size analysis and N2-adsorption and desorption means of composite materials were characterized results show that:the Ni-Al Hydrotalcite-like laminates have been successfully intercalated into the soap stone; composite particle size between the Ni-Al hydrotalcite and soapstone; DTA also showed that the layered composite material with high thermal stability, and structural damage to temperatures up to673℃.