THE ABILITY TO TREAT CYANIDE IN WASTE WATER BY H2O2 AND NaOCl

Abstract

This paper studies the ability to treat cyanide in wastewater with H₂O₂ and NaOCl. The research model includes 1 sedimentation tank with dimensions of 50x50x50 cm, a reaction cell with dimensions of 50x50x50 cm and a magnetic stirrer. The object of the research is wastewater collected at the selection line, copper and nickel mines - Cao Bang. Wastewater quality was surveyed 4 days from 5/3/2023 to 8/3/2023 with frequency 4 times/day at 1:00 am, 7:00 am, 1:00 pm and 7:00 pm. The model was operated with wastewater samples NT11 and NT15 collected at 13h on 7/3/2023 and 13h on 8/3/2023 with pH value and concentration of chlorine, CN respectively 8.8 and 8,7; 4459 and 3879 mg/l; 0.41 and 0.34 mg/l. The results of the survey on the influence of chlorine showed that the amount of chlorine treated by H₂O₂ in the studied conditions was very low, so it can be seen that chlorine has little effect on the CN treatment process at this condition. Analytical results showed that for research subjects with CN concentrations is about 0.34 - 0.41 mg/l, the dosage of 37% H₂O₂ and 82% NaOCl suitable for treatment was 1.0 : 0 ,5ml/l wastewater with a reaction time of 20 minutes. Output wastewater is in QCVN 40:2011 (column A) for total CN parameter.