Research On Treating Cyanide-containing Wastewater By High Voltage Pulse Discharge

In this paper, we use non-thermal plasma generating by high voltage nanosecond pulse to treat cyanide-containing wastewater. We design and use two kinds of reactors to discharge and treat wastewater, one is string-string electrode , the other is needle-board electrode. The experiment compared the removal efficiencies of CN by single-phase liquid discharge with two-phase mixture discharge. Many factors were discussed including pH value,reaction time,flux of gas,discharging conditions. We obtained some results as follow: 1) The removal efficiencies of CN go up gradually with pH value decreasing and reaction time prolonging when pH value is range from 8 to 13. 2) The removal efficiencies of CN increases with airflow rate adding continuously. Airflow rate l= 1.0L/min,pH=10.03, The removal efficiencies of CN can achieve 97.59%. 3) Higher is discharge voltage, better is removal result of cyanide-containing wastewater. 4) In front of 60 minutes ,the removal efficiencies of CN is higher by using needle-board electrode reactor to discharge and treating than by using string-string electrode reactor while airflow rate is 1.0L/min and pH value is range from 8 to 13.In the same of airflow rate which is 1.0L/min and reaction time which is in 60-120 minutes, pH value is range from 8 to 9, the treating result of CN of string-string electrode reactor is better than that of needle-board electrode reactor. While pH value is range from 10 to 12, treating result of CN by using string-string electrode is worse than by using needle-board electrode. 5) When pH value is range from 8 to 12, removal effect of CN is the best when let air flow into reactor to discharge, second is nitrogen gas. That is to say, the removal effect of CN by discharging with no air is worse than by discharging with nitrogen gas except pH value is 11.The removal efficiencies with no gas discharging is the lowest. 6) Removal effect of CN is good in ten minutes when mixture gas of SO2 and N2. The removal efficiencies of CN changes small with reaction time extending after reacting ten minutes. 7) When pH value is range from 8 to 11, value of volatilizing cyanides by string-string electrode treating is taller than that by needle-board electrode reactor treating .