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Cyanide and heavy metals pose significant risks as contaminants in certain industrial effluents. This study aims to concurrently eliminate cyanide and specific heavy metals from synthetic wastewater resembling gold processing effluent, employing an improved electrocoagulation method incorporating ozone and UV-LED. The investigation delves into the effects of pH, electrode type, current density, reaction time, and ozonation. The findings revealed notable removal efficiencies: 98% for cyanide, 76% for nickel, 85% for copper, and 84% for zinc when utilizing a stainless steel electrode as the cathode. Optimal removal rates were achieved at 94% for cyanide, 93% for copper, 92% for zinc, and 83% for nickel, employing the UV-LED-ozone technique with an ozonation flow rate of 4 mg/s at pH = 10. Notably, when Al-Gr-SS-Fe electrodes and a current of 15 mA/cm2 were applied, these removal efficiencies were observed. Therefore, the most favorable conditions for the concurrent removal of pollutants from synthetic wastewater involved maintaining a pH of 10, utilizing SS-Fe as anode and Al-Gr as cathode electrodes, and employing a current density of 15 mA/cm2. The addition of ozonation with a flow rate of 4 mg/s, along with UV-LED, further enhanced the removal process. In summary, it can be inferred that the enhanced electrocoagulation method outperformed conventional electrocoagulation, leading to increased elimination of cyanide and selected heavy metals. [ABSTRACT FROM AUTHOR]

One of the new methods used to remove the contaminants from effluent is the electrocoagulation method, which is sometimes combined with other methods to increase the removal efficiency of contaminants. To simultaneously remove nickel, cyanide, zinc, and copper, the combined method of photo-electrocoagulation was used along with an oxidizing agent, namely hydrogen peroxide (Hp). In addition, the effects of factors affecting the removal efficiency were studied, including pH, electrode arrangement, and current intensity. An electric current of 300 mA at a pH of 10 for 60 min, Fe-SS electrodes with a distance between them of 5 cm, and hydrogen peroxide at a rate of 4 mg/L were the ideal conditions needed to accomplish the photo-electrocoagulation-oxidation process. According to these study findings, when the combined method of photocatalyst-electrocoagulation-oxidation (Hp) was used, the highest removal efficiencies of nickel, cyanide, zinc, and copper were 85, 96, 94, and 98%, respectively. The results showed that using the combined photo-electrocoagulation-oxidation method increased the efficiency of simultaneous removal of pollutants by 10% compared to conventional electrocoagulation method. The reason for the increase in removal efficiency is the production of hydroxyl radicals simultaneously with the formation of coagulants produced by electrocoagulation process. [ABSTRACT FROM AUTHOR]