Vesicle-like silica (VS) was prepared by utilizing cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecyl sulfate (SDS) as a dual-template. The mesostructures of VS were characterized by N 2 adsorption-desorption isotherms, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Results showed that mean mesopore size of unilayer and multilayer VS was about 14 nm and shell thickness was nearly 6 nm. The VS was chosen as support for immobilization of Porcine pancreatic lipase (PPL) by physical adsorption. The immobilized PPL possessed excellent thermal stability and reusability in the hydrolysis reaction of triacetin in phosphate buffer solution.
Ordered mesoporous SBA-15 was synthesized through hydrothermal process under acidic condition. The material was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), small-angle X-ray diffraction (SAXRD), and N 2 adsorption-desorption. The results indicated that SBA-15 has 2-dimensional hexagonal p 6 mm mesoscopic structure and well-ordered parallel mesochannel. The as-obtained mesoporous silica was used for controlled release of water-insolube drug emodin. The loading capacity could achieve 6.64 mg/g, and the release profiles that studied in phosphate buffered saline (PBS, pH = 7.4) showed that released amount of emodin was 95.8 % after 48 h.
Mesoporous TiO 2 with high surface area ( S BET ) and different pore size was successfully fabricated via hydrothermal method using cetyltrimethylammonium bromide and PEO-PPO-PEO as the structure-directing agents, and tetrabutyl titanate (TBT) as titanium source. S BET and pore size of the materials were adjusted by using different amount of TBT. S BET was increased as TBT changing from 0.5 g to 1.0 g, and then dropped as 2.0 g TBT added. Among as-prepared samples (PC), PC-1.0 showed the highest S BET of 92.72 m 2 g 1 . With the increase amount of TBT, pore size increased from 10.36 nm to 12.72 nm. The phtocatalysis study showed that PC-1.0 had the highest percent degradation of 99.6 %. We believed that the design and synthesis of mesoporous TiO 2 with changing mesopores and S BET are important for both fundamental and technological viewpoints.
Rod-shaped TiO2 was synthesized via homogeneous precipitation by using PEG and urea as the structure directing agent and precipitation agent, respectively. The prepared samples were characterized by XRD, TEM, and FESEM. The XRD patterns of the samples indicated that the crystalline phase was anatase. TEM and FESEM images revealed the morphology of prepared TiO2 samples were rod-shaped, and densely packed with plenty of spherical-shaped units. RTS3 exhibited the highest photocatalytic activity for degradation of papermaking wastewater under UV light irradiation. CODCr percent degradation was about 75% under UV light irradiation in 12 h for RTS3.
Mesoporous silica with different morphological structure had been prepared using cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecyl sulfate (SDS) as co-surfactant templates and tetraethoxysilane (TEOS) as silica source. Variation on the morphological structure can be achieved by adjusting the solution conditions. The mesoporous silica with varied morphologies and pore structures were characterized by transmission electron microscopy (TEM), small-angle X-ray diffraction (SAXRD) and N2 adsorption-desorption isotherms. Based on experimental results, the mesoporous silica morphologies including vesicle-like and hollow nanospheres with mesoporous shell has been proposed. It was also observed a transformation from vesicle-like silica to hollow nanospheres with mesoporous shell by regulating the solution conditions.
Functionalized SBA-15 with mesoscopic pore channels was synthesized by co-condensation of tetraethoxysilane and (3-aminopropyl) triethoxysilane (APTES) via hydrothermal process. Small-angle X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy were used to monitor the effect of surface functionalization on the structural and textural features of the SBA-15. The results suggested that the structural ordering of functionalized SBA-15, as well as pore diameters, pore volumes and surface areas, were decreased with increasing the APTES molar ratio. Candida rugosa lipase (CRL) was used as a model enzyme for studying the effect of amino-functionalized on loading amount and enzymatic activity. The effects of pH and temperature on catalytic hydrolysis of tributyrin by immobilized CRL were investigated. The results showed that immobilized CRL had a well adaptability in a wide pH and temperature region, and CRL immobilized on functionalized SBA-15 exhibited much higher enzymatic activity than free CRL, especially, 5 mol% APTES functionalized SBA-15 immobilized CRL displayed the highest activity.
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