超声辅助电催化氧化降解水杨酸的研究

Study on the Ultrasound-assisted Electro-catalytic Oxidation of Salicylic Acid in Water

通过对水杨酸降解的UV扫描吸收光谱的研究表明,在水杨酸的电催化氧化和超声辅助电催化氧化降解过程中,都有吸收紫外光的中间体生成,对吸光度峰值随降解反应时间的变化关系进行非线性最小二乘法拟合(NLSF),发现其衰减均符合表观一级反应动力学规律;而COD值的衰减也都符合表观一级反应动力学规律。GC-MS检测到水杨酸超声辅助电催化氧化降解60 min后,有中间产物甲酸、乙酸、苯酚,认为是水杨酸在.OH的作用下,开环氧化降解生成乙酸和甲酸等小分子有机物,最后降解为二氧化碳和水。

The electro-catalytic oxidation and ultrasound-assisted electro-catalytic oxidation were used respectively to the degradation of salicylic acid.Through UV scanning spectra, it can be proved some intermediates that can absorb the UV light were produced in the degradation reaction.The absorbance peak varied with reaction time and the relationship was processed by NLSF.The results showed that the reductions of relative absorbance peak of the solutions treated by the two ways both met the pseudo first-order reaction kinetics. The intermediate formic acid, acetic acid and phenol were detected by GC-MS after 60 min of the degradation. It proved that salicylic acid was first degraded into small-size organic compounds by hydroxyl radicals, and finally into carbon dioxide and water.