Removal effects of acidulant on Cr and Cu in electroplating sludge
复合酸化剂对电镀污泥中铬、铜的去除效果

The removal effects of Cr and Cu from electroplating sludge were studied by using citric acid,nitric acid,hydrogen peroxide as compound acidulant and using ferric ion as synergist.The influences of compound acidulant concentration,reaction time,rotational speed,pH value and ferric ion concentration on the removal efficiency of heavy metals were investigated.The results showed that ferric nitrate was dissolved by 0.15 mol/L citric acid and 0.25 mol/L nitric acid containing 1.5% hydrogen peroxide,and the optimal mass concentration of ferric ion was 2.0 g/L.At the room temperature,keeping to sludge-liquid ratio at 1:10,the specimens were swung for 4 hours in the rotational speed at 150 r/min.And the max removal rates of Cr and Cu were about 80.02% and 92.89%,respectively.And the residual quantity of heavy metals in the sewage sludge was measured up to national standards of agricultural sludge.