UV facilitated synergistic effects of polymetals in ore catalyst on peroxymonosulfate activation: Implication for the degradation of bisphenol S

The use of natural ore, especially iron-based ore, in sulfate radical-advanced oxidation processes (SR-AOPs) for organic contaminant control has received increasing attention. However, the rapid exhaustion of Fe(II) in ore has become a bottleneck restricting persulfate activation and radical generation. Herein, a natural Ti- and V-enriched magnetite (Ti-V-M) was exploited both as an activator and catalyst for UV-facilitated peroxymonosulfate (PMS) degradation of bisphenol S (BPS) in a water treatment process. The results revealed superior performance in which 100% of BPS was removed within 20 min in the UV/PMS/Ti-V-M system, and its pseudo-first-order kinetic constant was almost 3.55 times, 42.73 times, and 52.22 times higher than that for the PMS/Ti-V-M, UV/PMS, and UV/Ti-V-M systems, respectively. Under the synergistic action of multi-metals, the photocatalytic activity of the Ti-V-M was greatly improved with relatively low valence band potential (1.88 eV) and charge transfer resistance (12.60 Omega). Meanwhile, distinct from conventional PMS processes activated by monometallic Fe, the Fe(III)/Fe(II) circulation was accelerated significantly, mainly due to the excited h(+)-e(+) pairs in photosensitive TiO2 and subsequent electron transfer by V(III)/V(IV)/V(V) redox cycles. The above advantages strongly enhanced radical generation, and SO4-center dot, center dot OH, O-2(-center dot), O-1(2) and h(+) were confirmed to play vital roles in BPS degradation. Furthermore, this system displayed excellent recyclability and stability for water treatment. Our study highlights the mechanism of synergistic action of multi-metals in natural minerals for UV-facilitated PMS activation and sheds new light on using cost-effective ores for highly efficient treatment of highly acidic and alkaline organic wastewater.