Catalytic degradation of Reactive Black 5 through peroxymonosulfate activation with Co organic frameworks combined with graphite oxide

The development of high-efficiency catalysts for peroxymonosulfate (PMS) activation is critical for pollutant treatment in environmental applications. In this research, a Co organic framework (CoHHTP) combined with graphene oxide (GO) (CoHHTP/GO) with a 2D structure was prepared for PMS activation to treat the azo dye Reactive Black 5 (RBK5). The combination of CoHHTP and GO via oxygen groups resulted in the high activity of CoHHTP/GO, and almost 100 % performance was achieved within 30 min under various pH, temperature, PMS loading, and catalyst loading conditions. The maximum RBK5 removal efficiency was obtained with a catalyst loading of 3.0 g L⁻¹, PMS loading of 0.5 mM, temperature of 25 °C, and pH of 6 with a pseudo-first-order kinetics k value of 0.1903 min⁻¹. The activation energy of the CoHHTP/GO/PMS/RBK5 system was calculated to be 14.34 kJ mol⁻¹. Meanwhile, radicals and nonradicals, including SO₄^·−, ·OH, ·O₂⁻, and ¹O₂, were proven to be generated and involved in RBK5 degradation. Moreover, RBK5 degradation pathways were identified through experimental research and density functional theory calculation.