Sonophotocatalytic Antibiotic Degradation Efficiency of g-C3N4/TiFe2O4
摘要
In this study, graphitic carbon nitride (g-C3N4) was synthesized from a waste melamine-formaldehyde product using a facile heat treatment process and combined with titanium ferrite (TiFe2O4), a magnetic semiconductor material, in the composite structure to investigate both sonocatalytic and sonophotocatalytic antibiotic degradation efficiencies. According to FTIR, XRD and XPS analyses, g-C3N4 and its composites with TiFe2O4 were successfully obtained. Compared with g-C3N4, the composite (g-C3N4/TiFe2O4) exhibited greater specific surface areas of 76.34 m2/g. The antibiotic removal experiments showed that g-C3N4/TiFe2O4 could remove 85.7% of tetracycline within 120 min by ultrasonic irradiation, and 91.9% of tetracycline when ultrasonic irradiation and visible light irradiation were applied together for 120 min. The high antibiotic removal achieved by g-C3N4/TiFe2O4 was attributed to the effective separation and transfer of sono/photogenerated charge carriers within the composite structure. The sonoluminescence, the visible light and the cavitation effect of the ultrasonic irradiation contributed to the formation of active radicals to degrade the antibiotic molecules. It was observed that the antibiotic concentration of the solution, catalyst dosage, and pH of the medium had limited effects on the tetracycline removal efficiency of the composite catalyst. According to the trapping experiments, both hydroxyl and superoxide radicals played important roles in the degradation of tetracycline. The sonophotocatalytic tetracycline degradation efficiency over the recycled composite sample reduced from 91.9 to 79.3% after five cycles. The novelty of this study was directed to the synthesis of high value-added sono/photocatalyst from waste melamine-formaldehyde material and to combine with magnetic nanoparticles.