Synthesis of ferrate by electrolysis of iron at extreme pH for remediation of aquatic environments from dye and antibiotic wastes

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Abstract The presence of dyestuffs and antibiotics in aquatic environments creates toxic contaminants and microbial resistance, which are harmful to human health and require special handling methods. The Advanced Oxidation Process method with ferrate (Fe(VI)) oxidising material has the potential for effective degradation of water pollutants, is environmentally friendly, and is easy to prepare. Therefore, in this study, ferrate synthesis from the electrolysis of iron at extreme pH for the remediation of the aquatic environment from waste dyes and antibiotics has been successfully carried out. Electrolysis was performed in a 14 M NaOH electrolyte using iron and zinc plates as anode and cathode electrodes, respectively. The effects of synthesis parameters such as time, NaOH concentration, and ferrate stability were observed. In addition, ferrate was applied to degrade the dyes methylene blue and the antibiotic ciprofloxacin. The degradation mechanism and application parameters such as pH, dosage, and time were also observed. The success of the synthesis was confirmed by the presence of FeO(OH) groups and the Na2FeO4 peaks characterised using FTIR, XRF, and XRD. Ferrate application for dyes obtained the best results on methylene blue degradation of 98% at pH 8 and a contact time of 70 minutes. The optimum ciprofloxacin degradation of 86.7% was obtained at pH 7 and 120 minutes. Dye degradation occurs through the breakdown of the C-S=C and azo (N=N) bonds. In contrast, in antibiotics, it occurs through the reaction of HFeO4 −/H2FeO4 with the active site of the piperazine ring. This shows that ferrate can potentially produce water remediation from dye and antibiotic waste for a better environment.