Construction of g-C3N4/CaMoO4 Composite with Higher Sonocatalytic Performance and its Combined Use with Persulfate and Hydrogen Peroxide for the Degradation of Organic Dyes
摘要
The development of new sonocatalysts is of vital importance for the heterogeneous sonocatalysis, an efficient advanced oxidation process, which is used for the degradation of organic pollutants. This paper effectively achieved the separation of charge carriers during the sonocatalysis process by constructing type II heterojunction of g-C3N4/CaMoO4. Particularly, when the mass percentage of g-C3N4 to CaMoO4 in the composite was 30%, the prepared g-C3N4/CaMoO4 composite (CC-30) exhibited the best sonocatalytic activity. Under the desired conditions obtained, 1.0 g/L of CC-30, when subjected to ultrasonic irradiation (500 W), showed a remarkable removal effect of organic pollutants in a 5 mg/L Orange II solution (pH = 6.5) within 120 min, reaching 91.73 ± 1.85%. The scavenger test indicated that in the sonocatalytic degradation process of Orange II, the redox reactions of active species such as •OH, O2−• and h+ play a crucial role. The degradation pathways of Orange II were proposed based on the degradation products of Orange II determined by LC-MS. The addition of auxiliary oxidants such as K2S2O8 (3 mmol/L) and H2O2 (5 mmol/L) could respectively achieve a degradation efficiency of 91.18 ± 0.94% and 94.25 ± 2.56% for Orange II within 60 min, effectively shortening the reaction time of the sonocatalytic process. Furthermore, the results of the reusability and stability tests also highlighted the remarkable efficacy of the aforementioned system in remedying contaminated water sources with organic substances. The observed results indicated that constructing g-C3N4/CaMoO4 heterojunction and its combined use with auxiliary oxidants had excellent application potential in the sonocatalytic degradation of organic pollutants in water and wastewater treatment.