Selective Removal of Penicillin Antibiotics in Wastewater by Rapid Hydrolysis in Goethite-Zn(II) System

Abstract

The high concentration of penicillin antibiotics in wastewater inhibits the function of biological treatment systems. In this study, we optimized the goethite (FeOOH)−Zn(II) system and used the hydrolysis pretreatment process for the selective removal of penicillin antibiotics from pharmaceutical wastewater. The results showed that penicillin antibiotics could be rapidly and completely hydrolyzed in 20 min with an FeOOH concentration of 500 mg/L and a zinc ions concentration of 30 μM, with a premixing time of 2 h at pH 8.2 and room temperature. The influence of cations on the system was found to be negligible, while phosphate and natural organic matter (NOM) had significant impacts on penicillin degradation, followed by that of bicarbonate. A mechanistic study suggested that these anions reduced the active sites of FeOOH−Zn(OH) 2 and affected the interaction between FeOOH and penicillin. Additionally, steric hindrance and hydrogen bond competition effects cannot be ignored. Furthermore, we proposed applying ferric chloride, which effectively pretreated the aforementioned interfering substances. Eventually, penicillin antibiotics were rapidly hydrolyzed in wastewater by the FeOOH−Zn(II) system effectively in 40 min. The findings in this study demonstrate that the proposed approach enhances the hydrolysis of penicillin antibiotics and may serve as a viable pretreatment technology for antibiotic wastewater.