Investigation of the Acid-Base Properties of Sodium Humate from Brown Coal of the Kaychak Deposit (Kemerovo Region) by Means of Photometric Titration
M. G. KORZH1, M. P. PIDGIRNY1, A. A. ZVEKOV2, O. N. BULGAKOVA1, A. S. NIKITINA3, and M. M. KOLOSOVA3
1Kemerovo State University, Ul Krasnaya 6, Kemerovo 650043 (Russia)
2Institute of Coal Chemistry and Material Science, Siberian Branch of the Russian Academy of Sciences, Sovetskiy Pr.18, Kemerovo 650000 (Russia)
3Kemerovo State Agricultural Institute, Ul. Markovtseva 5, Kemerovo 650056 (Russia)
Keywords: гуминовые кислоты, бурый уголь, фотометрическое титрование, рН-метрическое титрование, humic aicds, brown coal, photometric titration, рН metric titration
Abstract
The application of photometric titration to the studies of acid-base properties of humic acids is considered for sodium humate obtained from brown coal of the Kaichak deposit (Kemerovo Region, Tisul District) titrated with hydrochloric acid. The appearance of the curve of photometric titration corresponds to the case of coloured initial substance and reaction product, and uncoloured titrant. The concentration of acid centres and dissociation constant were determined as a result of titration curve treatment. To verify the results, pH metric titration was used. It was concluded that photometric titration allows more precise determination of the parameters of humic substances than the direct use of Bouguer−Lambert−Baer law and Henderson−Hasselbach equation.
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