Construction and characterization of CoWO4/g-C3N4 composites for efficient sonocatalytic degradation of Rhodamine B

In this paper, CoWO4/g-C3N4 composites with efficient sonocatalytic activity were fabricated by a modified polyacrylamide gel route combined with a facile ultrasound-assisted process. A variety of characterization methods have been adopted to confirm the phase purity, charge state, morphology, optical property, and sonocatalytic activity of CoWO4/g-C3N4 composites. The sonocatalytic activities of as-prepared composites were evaluated by the degradation of Rhodamine B (RhB). The high sonocatalytic degradation efficiency (84.8%) was achieved over 1 g/L CoWO4/g-C3N4 (7 wt%) composites and 10 mg/L RhB solution under ultrasonic irradiation (180 W, 40 kHz) for 180 min. The degradation efficiency of RhB over CoWO4/g-C3N4 (7 wt%) sonocatalyst is 6.6 times as high as that of pure CoWO4. Trapping experiments reveal that the sonocatalytic decomposition of RhB was mainly due to the production of superoxide radicals. A possible sonodegradation mechanism was proposed based on the sonocatalytic experiments, and stability and reusability of CoWO4/g-C3N4 composites were also studied. The CoWO4/g-C3N4 composites as an efficient sonocatalyst for the catalytic degradation of RhB have great potential in wastewater treatment. This work will provide a valuable reference for the construction and application of composite sonocatalysts.