Adsorption characteristics of ciprofloxacin and naproxen from aqueous solution using bamboo biochar

Adsorption of the drugs ciprofloxacin (CFX) and naproxen (NPX) using bamboo biochar was systematically investigated. Bamboo biochar was characterized by SEM, TEM, FT-IR, BET, and ζ measurement. Bamboo biochar has a porous structure with high specific surface area and contains carboxyl groups with negative charge. Batch adsorption of CFX on bamboo biochar was optimal at pH 4, 7.5 g/L adsorbent dosage, and adsorbed in 90 min while the best conditions for NPX adsorption were pH 3, with 10 g/L and contact time 90 min. Adsorption isotherms of CFX and NPX on bamboo biochar surface at different ionic strengths were achieved with Freundlich better than Langmuir. Adsorption of CFX and NPX on bamboo biochar is controlled by electrostatic and non-electrostatics, while NPX adsorption is mainly controlled by electrostatic interactions. The CFX and NPX removal efficiencies were still greater than 60% after four regenerations, indicating that bamboo biochar is an excellent adsorbent for pharmaceutical contaminants removal in water. Graphical abstract