Mechanism of sulfur removal from coal by microwave assisted acetic acid-hydrogen peroxide system

The desulfurization effect of Ningxia Shuangma coal (SM) with an acetic acid-hydrogen peroxide system assisted by microwave, ultrasonic and ultraviolet light was compared. The results show that microwave-assisted desulfurization has the best effect. When the microwave power is 900W, the irradiation time is 5 min, and the volume ratio of acetic acid to hydrogen peroxide is 1:10, the desulfurization rate can reach 55.82%. Moreover, microwave-assisted desulfurization can effectively improve the removal effect of organic sulfur. XRD, XPS, SEM and other characterization showed that microwave assisted can effectively reduce the mineral content, expose more sulfur-containing groups, and improve the desulfurization effect. The desulfurization rate of three sulfur-containing compounds is: dibenzyl sulfide > diphenyl sulfoxide > benzothiophene. With the increase of intensity of the applied electric field, the C–S bond gets easier to fracture, the applied electric field can reduce the reaction energy barrier, is a benefit to the reaction.