对电催化氧化和超声辅助电催化氧化降解苯酚过程中的UV扫描吸收光谱研究表明:在苯酚的氧化降解反应过程中,都有对紫外光有吸收的中间体生成;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),发现溶液的相对吸光度峰值的衰减均符合表观零级反应动力学规律,其相应的表观反应速率常数(k0)分别为(0.0051±0.0005)m in-1和(0.0052±0.0003)m in-1;但超声波对电催化降解苯酚的速度和效果并无显著影响。同时GC-MS也检测到苯酚超声辅助电催化氧化降解60 m in后,发现除苯酚仍然存在外,还有中间产物苯酚乙酸酯、甲酸、乙酸,从而证实苯酚在羟基自由基作用下,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 are used respectively to the degradation of benzoic acid.The UV scanning spectra provea some intermediates which between them can absorb the UV light the degradation reaction.Tabdorbance peak varies with reaction time and the relationship is proccessed by NLSF.The results show that the reductions of relative absorbance peak of the solutions treated by the two ways both meet the pseudo first-order reduction kinetics,and the pseudo rate constants(K0) are 0.007±0.0006 and 0.0075±0.0001,respectively.Besides benzoic acid,the intermediate formic acid,acetic acid and phenol are detected by GC-MS in the reaction system after degradation for 60 min.It proves that benzoic acid is degraded into small-size organic compounds by the hydroxy1 radicals.
