Silica gels model construction

The interaction of silica gel with VOCI3 was considered to be an opportunity for mathematical model construction of the process of volatile halogenides chemisorption on the disperse silica surface. 

Structure correlation data from scattering experiments could be used in conjunction with the adsorption isotherm to construct model disordered structures for specific silica gel adsorbents, using the methodologies described in Section ll.B for activated microporous carbons. 

Therefore, a silica-gel-based bonded phase was constructed. The new phase was constructed based on the dimetho)ypentylsilane-bonded poly-silicondioxide phase shown in Figure 3.13, and consisted of 991 atoms, 1051 bonds and 15 193 connectors, containing 171 silicons, 328 ojygens, 143 carbons and 349 hydrogens (Phase 4). Twenty dimetho ypentylsilanes and one trimethylsilane were bonded within an 900 area on the poly-silicondioxide phase. The trimethylsilane was considered an end-capped molecule. A pocket caused by a small molecule, trimethylsilane, was designed to follow the V-shape model of a porous silica gel. The optimized structure of a complex formed between this model phase and quinine is... 

Over the last several years, the number of studies on application of artificial neural network for solving modeling problems in analytical chemistry and especially in optical fibre chemical sensor technology, has increase substantially69. The constructed sensors (e.g. the optical fibre pH sensor based on bromophenol blue immobilized in silica sol-gel film) are evaluated with respect to prediction of error of the artificial neural network, reproducibility, repeatability, photostability, response time and effect of ionic strength of the buffer solution on the sensor response. 

It has been found that models for the structure of sol-gel silica spheres, constructed foom spin density and spin-spin relaxation time images, give rise to good predictions for tiie point of separation of mercury intrusion and retraction curves, and the level of mercuiy entrapment, found for experimental porosimetry data for the same material. This finding suggests that the MR images contain sufficient information to determine the level of mercury entrapment. Hence, this result supports the view that mercury intrusion and retraction within this material is determined by macroscopic (0.01-1 mm) heterogeneities in the spatial distribution of porosity and pore size. 

---