Adsorption of some quaternary onium salts on silica gel

Adsorption of organic molecules on silica surface

“…cetyltrimethyl ammonium bromide (37), benzyltrimethyl ammonium bromide (38) etc. was studied by Ghosh et al [131]. They found the adsorption isotherm to be pH-dependant.…”

Direct Analysis of Intraparticle Mass Transfer in Silica Gel Using Single-Microparticle Injection and Microabsorption Methods

“…Furthermore, the sorption and desorption processes in silica gel are significant as models of the transport and degradation of chemical compounds in natural particles in the environment. The adsorption rates of small molecules at a solid/liquid interface are very fast in silica gel systems; , so the sorption rates of solutes into silica gel particles can be successfully analyzed by an intraparticle diffusion model . On the other hand, desorption processes are not clarified and generally very complicated compared with the sorption processes in microparticle systems.…”

Single-Microparticle Injection and Microabsorptiometry: Direct Analysis of Sorption Processes

“…Therefore, the sorption rate of MB into the silica gel is governed by the diffusion in the particle in the present system. Although average sorption rates for varioussized silica gel particles were analyzed (not single-particle measurements) by a batch uptake method, the diffusion coefficients of the quaternary salts in the silica gel have been reported to be 1 × 10 −8 cm 2 /s, which is a slightly larger value than the diffusion coefficient of MB (8). The pore size and the pore volume of silica gel for the quaternary salt systems have been reported to be 7.5 nm and 0.4-0.5 ml/g (6.5 nm and 1.15 ml/g for the present system), respectively.…”