Fe-Sillenite Nanosheets with Strong Internal Electric Fields for Efficient Degradation of Ciprofloxacin in High-Salinity Wastewater

Currently, Fenton-like processes are effective for pollutant degradation but face challenges in high-salinity environments due to radical quenching and limited removal efficiency. To address this, our study introduces Bi 12 FeO 20 sillenite nanosheets with a pronounced internal electric field (IEF) as catalysts, which efficiently activate H 2 O 2 to generate a high concentration of superoxide radicals (•O 2 – ) on the catalyst’s surface, enabling highly efficient ciprofloxacin (CIP) degradation under high-salinity conditions. Experimental results show that the system achieves CIP degradation rates exceeding 98% within 8 min in 0.5 M solutions of NaCl, Na 2 SO 4, KCl, and MgCl 2, with no significant inhibition observed as salt concentration increases. In continuous-flow tests, the system operates stably for 100 h, maintaining an average CIP degradation rate of 93.1%. Both experimental and theoretical analyses reveal that the IEF of Bi 12 FeO 20 nanosheets is 2.95 times stronger than that of nanoparticles, resulting in a negative electric effect that reduces chloride-ion adsorption and promotes H 2 O 2 activation, thereby promoting localized •O 2 – production. This study offers a promising approach for applying Fenton-like technology to pollutant degradation in high-salinity environments.