Study of Aqueous Chemical Forms of Silicon in Organic-rich Waters

Abstract

The study of silicon species in organic-rich waters is a very significant problem. This type of waters is widely spread all over the world. It is characterized by a high content of humic substances, high color of water and low pH. In this regard, a certain determination of silicon concentration in this type of waters is impossible without a preliminary investigation of silicon species. The aim of this research is therefore an investigation of the ratio of silicon dissolved forms in organic-rich waters depending on the silicon concentration and the acidity of the water. The study of pH influence on silicic acids and a silicon-humic matter interaction was carried out using model solutions and natural bog waters (Tomsk region). It has been found that the degree of polymerization of silicic acids essentially depends on the acidity of a solution. Scanning of spectrophotometric measurements has shown that silicon does not form stable complexes with fulvic and humic acids in weak-acid media (рН 3-4). Studying the bog waters of Tomsk Region has shown that they (рН=3.66-3.80) contain only monomeric-dimeric and polymeric forms of silicic acids

The Origin of the Natural Water Chemical Composition in the Permafrost Region of the Eastern Slope of the Polar Urals

“…The fulvic acid concentrations decrease with an increase in pH. The behavior of soluble humic acid is practically independent of geochemical parameters of the aquatic environment [33,34]. The redox conditions are characterized by values Eh −68 to 347 mV.…”

Evidence of humic acid-aluminium‑silicon complexes under controlled conditions

“…Pokrovski and Schott (1998) reported that Si formed weak complexes in solution with simple organic ligands having carboxylic or phenolic functional groups. Kambalina et al (2014), however, concluded after spectrophotometric measurements that Si does not form stable complexes with fulvic and humic acids in weak-acid media (рН 3-4).…”

PDMPO: a specific silicon or silica, pH sensitive fluorescent probe?

“…6 These compounds, however, are generally not very soluble and have a low bioavailability. 7 In the liquid phase, dissolved Si is mainly in the form of monosilicic acid (H 4 SiO 4 ), which is the dominant hydroxylated Si species in aqueous solutions between pH 2 and pH 9.8. 8 When the concentration of dissolved Si in aqueous solution exceeds z10 À3 mol L À1 , polymerization of Si can occur in very varied forms depending on the species and nanoparticles particles present in solution.…”