Removal of metronidazole from wastewater by Fe/charcoal micro electrolysis fluidized bed reactor

The aim of the research was to investigate the removal of metronidazole from aqueous solutions by Fe/charcoal micro-electrolysis fluidized bed reactor. The effective variables influencing the metronidazole removal including the initial pH of the solution, the initial concentration of metronidazole, contact time, aeration rate and Fe/charcoal ratio were studied. The amount of secondary iron ions pollution in the reactor effluent was investigated by a flame atomic absorption device. Degradation reaction kinetics were studied. The removal efficiency of metronidazole in the actual hospital wastewater sample was investigated under optimal conditions of the reactor. The stability and performance of the reactor was investigated through 4 consecutive cycles. Data analysis was performed by SPSS-16. The maximum removal efficiencies were obtained in optimal conditions including pH: 7, the contact time of 70 min, aeration rate of 6 L/min, charcoal/Fe ratio 1:1 and initial concentration of metronidazole of 10 mg/L as 90 and 78 percent for synthetic solutions and actual wastewater respectively. No secondary pollution of iron ions was detected. In the study of linear kinetic models, the degradation process followed pseudo-first kinetic order. The Fe/charcoal micro-electrolysis system is well-suited for efficient removal of antibiotics from aqueous solutions and applies to industrial scale.