SORPTION PROPERTIES OF SILICА-CONTAINING CELLULOSE FROM RICE HUSK

Cellulose-based sorbents from renewable sources, more specifically, plant cell membranes, are getting increasingly used as solid-phase matrix carriers in hybrid reagent indicator test systems, since the sorbents can provide high sensitivity to the toxicants to be detected/determined due to combining two operations - concentration and registration of the analytical signal, directly in the sorbent phase. The study was aimed to reveal relationships between the properties of preserved natural silicon dioxide during oxidative-organosolv delignification of rice husk and on the sorption properties. In this work, it was produced paper samples of silicon-based materials from silica-containing rice husk ash residue from 0.3 to 32.5% by weight of the absolutely dry raw materials, as well as it was found that the higher the content of mineral component, the higher specific surface area and pore volume. It was revealed that while forming a paper sheet, «concentrating» of mineral components occurs on the mesh side, which results in decreasing the crystallinity index and doubling the SiO2 content. It has been shown that it is the mineral part that appears to be quite stably colored after the silicon-containing cellulose matrices have been impregnated with the reagent 1-(4-aminosulfonylphenyl)-3-phenyl-5-(benzylbenzimidazolyl-2) formazan. Retention of organic reagents in the silica phase does not interfere with the chromogenic complexation reaction when the reagents interact with aqueous solutions of Cu (II) and Zn(II) salts. The contrasting color transition observed can be used for design of solid-phase reagent indicator test systems to detect copper (II) and zinc (II) ions in aqueous media.