Resource utilization of steel converter slag: Efficient degradation of typical organic flotation reagent α-nitroso-β-naphthol via the synergy of radical and non-radical pathways

Abstract

The organic pollution generated during production and processing in the mining area seriously endangers the ecological security of the surrounding environment. In this study, degradation of α-nitroso-β-naphthol (αNβN), a typical organic flotation reagent in mining area, by using steel converter slag (SCS) as a low-cost catalyst was reported for the first time. The results showed that SCS + H2O2 could effectively remove αNβN from water solutions. In the system used in this study, more than 98.8 % of αNβN could be removed within 60 min. Based on the analysis of the experimental results, the synergistic mechanism of radical and non-radical pathways was proposed. The radical pathway mainly consisted of OH radical oxidation, while the non-free radical pathway consisted of 1O2 and electron transfer. Fe, bridging OH and terminal OH on the surface of SCS were the active sites for H2O2 activation. The removal performance of the system was not affected by common coexisting ions, and showed strong anti-interference ability. After 4 times repeated use, the removal efficiency still reached more than 83 %. HPLC-MS was used to analyze the intermediate products, while the changes in their toxicity effects were analyzed by microcalorimetry for the first time. The results showed that the system could effectively reduce the ecotoxicity of a water solution containing αNβN. This study provides not only a new strategy for treating organic pollution in mining areas, but also a new idea for the green cycle development of industry and mining from the perspective of “treat the wastes with wastes”.