Effective benzalkonium chloride degradation by Fenton oxidation with iron–carbon–bentonite–alginate beads

Novel iron–carbon–bentonite–alginate beads (Fe/C-BABs) were prepared by sol–gel method to trigger advanced Fenton oxidation to realize benzalkonium chloride (BAC) degradation. Degradation results revealed that the optimal conditions of H2O2/Fe/C-BABs for BAC degradation were pH 3.0, [BAC] = 50 mg/L, [H2O2] = 60 mM, and [Fe/C-BABs] = 50.0 g/L (wet weight). BAC removal efficiency reached 87% within 30 min. Results indicated that BAC degradation was mainly attributed to the heterogeneous rather than the homogeneous reaction. The catalyst showed high-efficiency catalytic performance and ability to control metal-ion leaching to avoid environmental pollution. To expound the pathway of BAC degradation, gas chromatography–mass spectrometry analysis method was used to examine the intermediate products, and a plausible degradation pathway was also proposed. The oxidation of the benzene ring and long-chain alkane into organic acids indicated BAC degradation and nontoxicity of the products.