Diatoms are unicellular algae and occur ubiquitously in almost every marine freshwater habitat on earth. They produce intricately structured cell walls, which mainly consist of amorphous silica. To synthesize their diatoms take up monosilicic acid from the environment store it. These silicon storage pools (SSPs) can exceed solubility silicic by one to two orders magnitude, as observed various d...

ethylene polymerization was carried out using phillips chromium catalyst based on silica supports such as silicaaerogel, sio2 (grace 643), and titanium modified sio2 (g 643), and the results were compared with othercatalysts based on sio2 (aldrich), sba-15(hex), sba-15(sp) and mcm-41. a combination of tga, dsc, xrd,nitrogen adsorption, sem, icp, ftir and other analyses were used to characterize...

“Silica,” is a term which refers broadly to the mineral compound silicon dioxide (SiO2). Silica can be crystalline or amorphous. Crystalline silica is significantly more hazardous to employees than amorphous silica. In addition to causing the disabling and irreversible lung disease known as silicosis, crystalline silica has been classified as a human carcinogen by the International Agency for R...

Here we report on self-assembly of novel multi-hierarchically structured meso(nano)porous colloidal silica particles which have cylindrical pores of 4-6nm, overall size of ∼10μm and "cracks" of 50-200nm. These cracks make particles look like micro-sponges. The particles were prepared through a modified templated sol-gel self-assembly process. The mechanism of assembly of these particles is inve...

This study examined the preparation of high-capacity silica supports containing immobilized protein G. A maximum content of 39 mg protein G/g silica was obtained when using 100 A pore size silica, followed by 33 mg/g for 50 A silica and 9.3-24 mg/g for 300-4000 A silica. The surface coverage of protein G increased with pore size, with a maximum level of 0.037 micromol/m(2) being obtained for 40...

The development of nano-materials is viewed as one of the most important technological advances of the 21st century and new applications of nano-sized particles in the production, processing, packaging or storage of food are expected to emerge soon. This trend of growing commercialization of engineered nano-particles as part of modern diet will substantially increase oral exposure. Contrary to ...

The parameters of the alkaline fractionation process were investigated and optimized using a statistical analysis method to simultaneously remove hemicellulose ash from rice husk (RH) concomitantly. After process, residual solid contained high cellulose, recovery yield was enhanced in fractionated liquid hydrolyzate. hemicellulosic sugar (71.6%), de-ashing (>99%), lignin removal (>80%) ob...

extensive application of silica nanoparticles (snps) in various industrial products has led to the development of silica extraction methodologies out of various waste products. rice husk is an agricultural waste with a high content of amorphous silica. however, the presence of metal ion impurities and unburned carbon in the rice husk content may present an adverse effect on product color and pu...