Simultaneous removal of Se(IV) and ciprofloxacin from water by shrimp shell biochar/nano zero-valent iron.

Aiming at the potential hazard of the wastewater with the coexistence of selenium and antibiotics in selenium-enriched aquaculture, nano zero-valent iron (nZVI) was in situ synthesized on the N-doped porous biochar (NBC) prepared by shrimp shells, resulting in the composites (NBC-nZVI) with active functional components of NBC and nZVI. The samples were characterized by scanning electron microscopy (SEM), nitrogen adsorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Taking Se (IV) and ciprofloxacin (CIP) as the targeted pollutants, the simultaneous adsorption behavior of NBC-nZVI was investigated. The results showed that the removal performance of NBC-nZVI toward CIP and Se( IV) was superior to that of NBC and nZVI. Se (IV) was preferentially adsorbed on the surface of NBC-nZVI compared to CIP, which mediated the adsorption of CIP and improved the removal performance of NBC-nZVI to CIP. The adsorption of NBC-nZVI for Se(IV) was nearly immune to CIP. The adsorption behavior of NBC-nZVI toward CIP and Se( IV) in the bicomponent system followed the pseudo-second-order kinetics and Sips isotherm model, and the theo-retical maximum adsorption capacities for CIP and Se(IV) were 130.6,335.7 mg/g, respectively. [ABSTRACT FROM AUTHOR]