Removal of Nitroaniline From Water/Ethanol by Electrocoagulation Using Response Surface Methodology

The efficiency of electrocoagulation using iron electrodes (Fe-0) for the removal of aqueous nitroaniline derivatives (ortho-, meta-, para-) was optimized. Investigated operational parameters include: (i) the current density (318-1542 A/m(2)); (ii) the pH value (1-11); and (iii) the ethanol level (1-25%). Experimentally, both classical method and response surface methodology were used. Additionally, the D-optimal design was used to characterize the interactions between current intensity, initial pH value and ethanol level. Using the D-optimal design aimed at characterizing the impact of ethanol level on the extent of nitroaniline removal. The results showed that the optimal conditions for efficient nitroaniline removal were the following: (i) 5 min electrolysis time; (ii) 200 mg/L initial nitroaniline concentration; (iii) 1274 A/m(2) current density; (iv) 6 g/L NaCl; (v) initial pH value of 11; and (vi) 1% ethanol level. It appears that the current intensity (current density) is the most influential parameter, followed by the pH value and the ethanol level. The experimental setup was validated by successfully treating river water contaminated with tested nitroanilines under optimal conditions.