Silica gel

About: Silica gel is a research topic. Over the lifetime, 22313 publications have been published within this topic receiving 325516 citations. The topic is also known as: Amorphous silica & Precipitated amorphous silica.

Estimation of the distribution of surface hydroxyl groups on silica gel, using chemical modification with trichlorosilane

Abstract: An estimate of the relative distribution of the free and bridged surface hydroxyl groups is made, using a surface modification with trichlorosilane according to the following main reaction Si—OH + HSiCl3→Si—O—SiHCl2+ HCl. The amount of chemisorbed chloride groups on the substrates is compared with data on the total amount of surface hydroxyl groups and with hydroxyl group information derived from infrared spectra. The interpretation of these data gives an indication of the reactivity, distribution and concentration of the different types of hydroxyl groups on the surface of silica gel.Trichlorosilane reacts mainly with bridged hydroxyl groups on silica gel, pretreated at low temperatures and exclusively with free hydroxyls at high pretreatment temperatures.Extrapolation of the reactivity of trichlorosilane towards the surface hydroxyl groups demonstrates that bridged hydroxyl groups are present up to pretretment temperatures of 973 K.

Improved calorimetric method to investigate adsorption processes from solutions onto solid surfaces

Abstract: Donnees sur un dispositif calorimetrique permettant les mesures des chaleurs differentielles d'adsorption et de dilution. Donnees sur la methode utilisee et applications a l'adsorption d'ether d'octylphenyle de polyethylene glycol (Triton X100) sur du gel de silice et du charbon actif

Carbon Paste Electrode Modified with Functionalized Nanoporous Silica Gel as a New Sensor for Determination of Silver Ion

Abstract: A new dipyridyl-functionalized silica gel (DPSG) was synthesized. The potentiometric response of silver ion was investigated at a carbon paste electrode chemically modified with functionalized nanoporous silica gel. The electrodes with a DPSG proportions of 10.1% (w/w), showed very stable potential. Calibration plots with Nernstian slopes for Ag+ were observed, 58.7 (±0.9) mV decade−1, over a wide linear range of concentration (5.0×10−7 to 1.0×10−1 M). The electrode has a detection limit of 1.0×10−7 M. The selectivity coefficients measured by the match potential method in acetate buffer, pH 5.5, were investigated. The electrode has fast response time, high performance, high sensitivity in wide cation activity ranges, and good long term stability (more than 6 months). The method was satisfactory and used to determine the concentration of silver ion in waste waters contaminated by this metal.