Research of the silicon aqueous forms in organic-rich natural water

Abstract

The chemical aqueous forms of silicon in organic-rich waters have not been well studied. Such waters are widespread in Tomsk region and they contain a lot of decomposed organic matters represented by fulvic- and humic acids which give them coloration (yellow coloring) and makes it difficult to identify the total concentration and forms of silicon content. Therefore, the reliable determination of silicon content in these waters is impossible without a preliminary assessment of its forms of occurrence. The main aim of the study is the research of chemical aqueous forms of silicon in organic-rich waters in Tomsk region using different type of fractionation: depolymerization and ultrafiltration, as well as to choose the optimal method for determining the mass concentration of silicon and forms of its location. The methods used in the study: molecular spectrophotometry, atomic absorption spectrometry - membrane filters IFAS-operating with a pore diameter of 0,45 and 0,05 microns. The results: Using the model solutions and natural waters (Tomsk region) the authors have studied the influence of pH on silicon-humic matter interaction. Spectrophotometric measurements shown that silicon does not form stable complexes with fulvic and humic acids in weak-acid media (рН 3-7). Studying the natural waters of Tomsk Region it was shown that the acid waters (рН=3,66-3,80) contain only monomeric-dimeric and polymeric forms of silicic acids. The reliability of the results verified by the reference analysis technique which is called spectrophotometric determination of silicon in the form of a yellow silicon-molybdic complex.

Keywords

• silicon
• silicic acids
• aqueous silicon forms
• organic-rich waters
• Tomsk region
• molecular spectrophotometry method