Comparison of hydroxyl radicals generation during granular activated carbon regeneration in DBD reactor driven by bipolar pulse power and alternating current power

Hydroxyl radicals (OH) is a kind of critical active species produced in the process of discharge plasma. We employed an innovative method to explore the OH generation features during granular activated carbon (GAC) regeneration in a DBD reactor, which was driven by a bipolar pulse power and an alternating current (AC) power, respectively. This measure was used the salicylic acid (SA) as a OH scavenger, which was adsorbed on GAC. And then the amount of OH was determined by the SA extracts from GAC using HPLC. The influence of the reactor supplied power on OH generation was assessed respectively powered by bipolar pulse and AC power. Besides, the effects of applied voltage, air flow rate, and GAC water content on OH formation were also evaluated under the two powers. Results showed that the greater discharge strength and air support were in favor of higher OH generation, and an optimal value of 20% for GAC water content was also observed. Moreover, the OH formation and its energy efficiency supplied by bipolar pulse power were both superior than AC power. Correspondingly, the phenol degradation on GAC and GAC regeneration motivated by bipolar pulse power were also enhanced than AC power.