Acid Orange 7 (AO7) is one of the most common azo dyes; however, its strong azo bond makes them difficult to biologically degrade. We sought to degrade AO7 dye using CeO2 as a promising alternative photocatalyst. CeO2 powders were synthesized with alternative monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) as a precipitant by solvothermal process combined calcination in air. Compared to the oxygen storage capability of Blank-CeO2 (0.186 mmol O2/g), that of MEA-CeO2 synthesized in the presence of MEA as a precipitant increased by 21.0%, while that of DEA-CeO2 and TEA-CeO2 synthesized in the presence of DEA and TEA as precipitants were decreased. Importantly, such MEA-CeO2 exhibited the highest photocatalytic activity than Blank-, DEA-, and TEA-CeO2 in degradation of AO7 under simulated sunlight illumination, and the removal rate of AO7 by MEA-CeO2 could reach 98.3% within 100 min.
Lei Wang,Chuyang Liu,Guoyue Xu,Shanshan Xiang,Mengyu Shi,Yujing Zhang
CeO 2 powders with flaky morphology and high floating rate are fabricated successfully by ball-milling and stearic acid modification. The influences of ball-milling time and surfactant stearic acid content on the morphology, floating rate, infrared emissivity of CeO 2 powders as well as the CeO 2 /epoxy-silicone coatings have been investigated systematically. The results show that the CeO 2 powders transform from irregular grains with larger size to flake grains with smaller size by ball-milling for 4 h. The floating rate of CeO 2 enhances from 0 cm 2 /g to 89.06 cm 2 /g by increasing stearic acid content from 0 wt% to 1 wt% while diminishes to 60.477 cm 2 /g with stearic acid content of 3 wt%. Ultimately, the coating with CeO 2 fillers ball-milled by 4 h and modified by 1 wt% of stearic acid exhibits the lowest emissivity value of 0.831 in the 8–14 μm waveband. The mechanisms for small and flaky fillers as well as high floating fillers to achieve low emissivity coatings are also fully revealed.