Oxygen vacancy-promoter on flotation residue carbon from coal gasification fine slag for the catalytic degradation of phenol

To enable the high-value application of coal gasification slag, flotation residual carbon from coal gasification fine slag (FSC) was used as a catalyst to remove organic contaminants. In this study, residual carbon was washed and sieved to prepare a stable carbon-based catalyst, which was used to activate peroxymonosulfate (PMS) for phenol degradation. The findings demonstrated that 50 mg/L of phenol could be removed by the FSC in 30 minutes within 30 °C, pH 3.01–11.00, 1 mmol/L PMS, and 0.6 g/L catalyst dosage. The efficiency of phenol degradation was attributed to the abundant active sites, such as oxygen vacancies in FSC. The characterization results demonstrated that oxygen vacancies, as a defective structure, could promote the adsorption of PMS on the FSC surface, then forming various active species, such as ·O2- and 1O2. Moreover, the presence of oxygen vacancies could redistribute the charge on the FSC surface, thus improving the adsorption and degradation of phenol. Overall, the study confirmed the activation potential of the flotation residual carbon from coal gasification fine slag and provided a theoretical foundation for its application in the catalytic removal of organic pollutants.