Nitrogen-rich cobalt metal–organic framework as a heterogeneous catalyst for the degradation of organic dye pollutants in water via peroxymonosulfate activation

Abstract

Metal organic framework (MOF) materials have attracted widespread interests because of their potential application prospects in the field of heterogeneous catalysis. In this work, a cobalt-based MOF Co₃-btca was developed as an efficient heterogeneous catalyst for the degradation of organic dye pollutants in water by activating peroxymonosulfate (PMS). Detailed characterizations showcased that the as-prepared nitrogen-rich Co-MOF Co₃-btca possessed micron size and good stability. In the presence of both Co₃-btca and PMS, the methyl violet (MV) degradation rate reached 99.78% within 9 min, while the rhodamine B (RhB) degradation rate reached 99.58% within 15 min. The effect of dye concentrations, reaction temperature, PMS and catalyst dosages on degradation reactions was studied. More importantly, successive degradation experiments demonstrated that the as-prepared Co₃-btca catalyst possessed good stability with easy recycling for eliminating organic contaminants from wastewater. Radical trapping measurements confirmed that SO₄⁻˙ and ˙OH radicals were the main active species for the removal of organic dyes. Moreover, we speculated the possible degradation mechanism of organic dyes. These features make Co₃-btca a stable heterogeneous catalyst for the efficient activation of PMS in environmental remediation.