Simultaneous adsorption of ciprofloxacin and Cu2+using Fe and N co-doped biochar: Competition and selective separation

The treatment of combined antibiotics and heavy metals pollution is a critical challenge. Herein, iron and ni-trogen co-doped biochar (Fe/N-BC) was synthesized using rape straw as precursor, and applied for the adsorption of ciprofloxacin (CIP) and Cu2+ in single and binary systems. The qmax for CIP and Cu2+ were 46.45 mg g � 1 and 30.77 mg g � 1, respectively. Adsorption decreased in a binary matrix, indicating that there was a competitive effect between CIP and Cu2+, which might be due to CIP and Cu2+ sharing similar active adsorption sites on Fe/ N-BC. Interestingly, CIP and Cu2+ co-adsorption was a pH-dependent process. Fe/N-BC has potential to highly selectively separate CIP/Cu2+ from mixed solutions through adjusting pH values. Furthermore, adsorption mechanisms were systematically investigated in this research. This research could help to provide a deeper understanding of the synchronously removing specific antibiotics and heavy metals by biochar adsorbents.

Automated summary

In this study, iron and nitrogen co-doped biochar (Fe/N-BC) was synthesized and applied for the adsorption of ciprofloxacin (CIP) and Cu2+ in single and binary systems. The adsorption of CIP and Cu2+ was found to be competitive due to the similar active adsorption sites on Fe/N-BC. Furthermore, the co-adsorption of CIP and Cu2+ was pH-dependent, and pH adjustment could selectively separate CIP/Cu2+ from mixed solutions.