Alginate/MIL-88B(Fe) derived magnetic biochar bead for non-radical degradation of organic pollutant with low peroxymonosulfate consumption

In this study, magnetic biochar bead ((AB + MIL-88)-C) was prepared by pyrolyzing MIL-88B(Fe) loaded alginate beads. The Fenton-like activity of (AB + MIL-88)-C was then investigated through activating peroxymonosulfate (PMS) for bisphenol A (BPA) degradation in water. The results demonstrated that (AB + MIL-88)-C exhibited superior BPA degradation capability (k = 0.160 min(-1)) than pristine MIL-88B(Fe) and alginate bead derived catalysts (k = 0.089 & 0.008 min(-1)), in which non-radical mechanisms including singlet oxygen (O-1(2)) and electron transfer process contributed over 98 % of BPA degradation. Moreover, PMS consumption rate by (AB + MIL-88)-C during whole BPA degradation process was very low. Consequently, the non-radical pathway dominated oxidation system with low PMS consumption rate could maintain its activity regardless of the fluctuation of environmental parameters and water matrices. Besides, it was further demonstrated that the reaction system exhibited high degradation selectivity in which those pollutants with electron donating groups were more inclined to be degraded. Meanwhile, the degradation rate (lnk) of respective pollutant in the reaction system correlated well (R-2 = 0.97) with their highest occupied molecular orbital position. This study provides a strategy for the development of non-radical oxidation systems with high pollutant degradation efficiency, stability and selectivity.