Synergistic degradation of methylene blue by laser cavitation and activated carbon fiber

Abstract

Methylene blue is widely used, but highly toxic and difficult to be degraded. In this paper, a new method of synergistic degradation of methylene blue by laser cavitation and activated carbon fiber is proposed. This paper theoretically studies the synergistic degradation effect, including radical oxidation effect, shock wave breakdown effect and activated carbon fiber surface adsorption effect. The deep degradation of methylene blue was studied experimentally, and the key influencing factors were analyzed. The results show that: the reason why methylene blue can be degraded is because of the oxidation effect of hydroxyl radicals, thermal decomposition and adsorption of molecules on the surface of carbon fibers. The main factors affecting the degradation rate of methylene blue solution are laser energy and initial concentration of solution. The degradation rate increased by 37.4% with the increase of laser energy (12–48 mJ) and decreased by 2.6% with the increase of initial concentration (0.01–0.05 mg/ml). The maximum degradation rate (93%) of methylene blue solution was reached at 48 mJ and 0.01 mg/ml for 30 min. Compared with the traditional adsorption degradation of carbon fibers, the degradation rate of the synergistic degradation of methylene blue solution by laser cavitation and activated carbon fibers can be increased by about 80% in a short time (30 min).