Exploration on the action mechanism of microwave with peroxyacetic acid in the process of coal desulfurization

•The cleavage of sulfur-containing bonds was improved under the extra microwave field.•The extra microwave field with peroxyacetic acid could promote desulfurization reactions.•The absorption efficiency of microwave energy for sulfur groups increased with the oxidation degree.•CS bond dissociation energies decreased with the oxidation degree of sulfur groups in coal.