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BUNDUCHI, Elena; GLADCHI, Viorica; DUCA, Gheorghe. Chemical autopurification of active blue dye-polluted natural water. In: Ecological and environmental chemistry 2017The 6th International Conference. 2-3 martie 2017, Chișinău. Chisinau, Republic of Moldova: Academy of Sciences of Moldova, 2017, p. 69.
|Ecological and environmental chemistry 2017 2017|
Conferința "Ecological and environmental chemistry 2017" |
Chișinău, Moldova, 2-3 martie 2017
This work reports the results on the catalytic-redox reactions of active blue dye textile in natural water-model system. Therefore, for this purpose, has been employed the system that reproduce the chemical composition of the dyepolluted natural water, [AA-O2-H2O2-CuII] (AA = active blue dye textile). As at higher values the process does not occur, the measurements were performed at pH~5.5. The oxidation reaction was monitored spectrophotometrically by measuring the decrease in absorbance at 602 nm (AA = 6, 2·103 M-1·cm-1). The experimental data is showing that chemical oxidation rates of active blue dye in [AA-O2-H2O2-CuII] system are directly proportional with oxidant and catalyst concentrations and inversely proportional with substrate concentration (see the equation below). The formation of free OH. radicals have been proven also spectrophotometrically by consuming of radical-acceptor dye, 4- nitroso-N,N-dimethylaniline (PNDMA). 0,4 0,4 0,4 9 2 2 9,37 10 AA H O Cu II W In order to reproduce the natural chemical composition of water autopurification, it was added to the experimental model, [AA-O2-H2O2-CuII], different ammonium salts (NH4X) and oxalic acid as a chelating compound. Their concentration was maintained similar to natural water systems. It was observed that these compounds have different influence on the blue dye oxidation rates. Therefore, ammonium ions are increasing the chemical oxidation rates 1,2 times while oxalate ions are decreasing the chemical oxidation rates 5,7 times. Anions of mineral acids (X-) don’t have any influence on the blue dye oxidation rates.