Abstract:

In order to investigate the effect of electrocoagulation on the treatment of cadmium plating wastewater from iron and steel plant,the aluminum iron electrode was activated and pretreated,and then the principle of electrocoagulation was used to remove and purify cadmium ions in the wastewater.The polarization effect of aluminum electrode was systematically analyzed,and the factors affecting the average particle size,content and removal rate of cadmium ion were discussed.The results showed that the optimal electrolysis time was 70 min,and the average particle size of flocs was 54 μm and the content was 3.80 g/L.The anodic polarization effect of Al Fe electrode was stronger than the cathodic polarization effect.When the initial pH value was 4.0,the plate spacing was 20 mm,the plate voltage was 5 V,and the current density was 30 mA/cm²,the primary removal rate of Cd²⁺ reached 96.8%,and the tertiary removal rate exceeded 99.9%.The content of Cd²⁺ in wastewater reached the current national discharge standard of electroplating pollutants.The experimental results showed that the electrocoagulation method was effective in the treatment of cadmium plating wastewater by aluminum iron electrode.

Key words: Al-Fe electrode, cadmiμm plating wastewater, electrocoagulation, separation and purification