Pharmaceutical residues can cause serious water pollution problems, harm human health and destroy the ecological balance. FeSO4·7H2O optimisation of the earthed atomising corona discharge (Fe-EACD) process was used to dispose of pharmaceutical wastewater in this research. Experiments were analyzed by VI characteristic curves to optimise the electrode distance (20-50 mm) and wire electrode diameter (0.3-0.5 mm). The effects of discharging voltage (7-12 kV), time (0-54 min) and FeSO4 dosage (0.2-1.2 g/L) were investigated using the response surface methodology (RSM). According to the RSM results, the best removal efficiency of COD (89.6%) was detected at the optimal discharging voltage of 12 kV, time of 42 min and Fe2+ concentration of 0.4 g/L. The Fe-EACD process could work efficiently with BOD5/COD ratio moving to 0.49 in an acid environment. The kinetic analysis and mechanism study suggested that the Fe-EACD process was demonstrated well by the pseudo-first-order based on the correlation coefficient (R2). Active •OH producing in the EACD process is responsible for the COD removal and the FeSO4·7H2O as a catalyst can promote the formation of active hydroxyl. In other words, EACD with Fe2+ optimisation was an economic and feasible process for pharmaceutical wastewater treatment.
Keywords: Electrochemical technique; active hydroxyl; corona discharge; pharmaceutical wastewater.