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ENGINEERING JOURNAL CHIANG MAI UNIVERSITY


Volume 26, No. 03, Month DECEMBER, Year 2019, Pages 14 - 24


Effect of environmental conditions and kinetics of laccase on dicofol removal

Apinya Onsarn and Karnika Ratanapongleka


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This research shows the usage of enzyme laccase to remove dicofol based insecticide. The Laccase was extracted from Lentinus polychrous Lev. It was found that the purity of laccase increased 3.52 folds when passing through micro- and ultra-filtration system. The result of using this enzyme to remove dicofol at 12 hours showed that the removal efficiency reached 100% at pH 7, temperature of 35ºC, the activity of the enzyme at 4.32 U/ml and dicofol concentration of 1 mg/l. The kinetics study on dicofol removal with laccase showed that the value of Km was 2.52 mg/l and Vmax was 0.93 mg/l/min. To determine the activation energy (Ea), the temperatures in the range of 25-35ºC were applied. The value of Ea was 5.45 KJ/mol. According to real environmental condition, the contaminations of NOM,Fe2+and Mn2+ were investigated. At dicofol concentration of 5 mg/l and the concentrations of NOM, Fe2+and Mn2+ in the range of 0-50 mg/l displayed that the removal efficiency increased when increasing the concentration of Mn2+. The removal efficiency reached 100% at Mn2+ concentration of 50 mg/l. In contradiction, in case of NOM and Fe2+, increasing the concentration of NOM and Fe2+ trended to decrease dicofol removal efficiency. The removal efficiencies at the concentrations of 50 mg/l were 62.43 and 45.32%, respectively. The results of inhibition study on NOM, Fe2+ and Mn2+ showed that NOM and Fe2+ were uncompetitive and competitive inhibitors, respectively, meanwhile, Mn2+ acted as a promotor for dicofol removal.


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ENGINEERING JOURNAL CHIANG MAI UNIVERSITY


Published by : Faculty of Engineering Chiang Mai University
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