Treatment characteristics of textile wastewater and removal of heavy metals using the electroflotation technique

The present work experimentally studied the clarification of wastewater using the electroflotation technique (EF) with aluminum electrodes. In the first part, we have studied the principal parameters (feed tension U, distance between electrodes D, period of treatment t, pH and conductivity κ) affecting the process using a simulated model of wastewater. The application of the optimized parameters (U = 20 V, D = 1 cm, t = 20 min) on an industrial wastewater derived from an Algerian velvet manufacture showed a high removal of biological oxygen demand after 5 days (BOD5 = 93.5%), chemical oxygen demand (COD = 90.3%), turbidity (78.7%), suspended solids (SS = 93.3%) and color (>93%). In the second part, we have studied the separation of some heavy metal ions such as iron, nickel, copper, zinc, lead and cadmium. This allowed us to show that the kinetics of electroflotation is very quick <15 min), and the removal rate reaches 99%.

Fig. 11. Removal efficiency of various metals — polymetallic solutions: C0 = 100 mg/L, feed tension U = 20 V, interelectrode distance D = 1 cm, initial pH = 8, conductivity κ = 2.7 mS/cm. experiments. The concentration of each model solution was 100 mg/L, initial pH was 8 and conductivity was 2.7 mS/cm. The experimental results are presented in Fig. 10. Fig. 10 shows that the kinetics of EF process is fast. We also note that the effectiveness of treatment of Ni(NO3)2 is 97.5% after 5 min, then it decreases to around 94%, to take again its initial value at 25 min.