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利用自制纳米TiO2薄膜作电极,对苯甲酸光电催化降解过程进行了系统研究.同时利用扫描电镜(SEM)、X射线衍射图谱(XRD)和光电流-电压响应谱分析光催化剂的微观性质和光电性能.选取较高的pH10.5,以利于苯甲酸降解中间产物的检测(GC/MS).通过对比光电催化与单一的TiO2光催化体系中苯甲酸的降解动力学、总有机碳(TOC)的去除率、降解产物的生成(GC/MS)及活性自由基物种的产生(ESR),提出光电催化降解苯甲酸的具体反应路径和氧化机理.羟基化的苯甲酸在羟基自由基与活性氧自由基的共同作用下,经由含六个碳原子的二酸(顺式己二烯二酸),被进一步氧化成小分子酸和CO2.
The photocatalytic degradation process of benzoic acid was systematically studied by using self-made nano-TiO2 film as electrode.The microscopic properties and photoelectric properties of photocatalyst were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photocurrent-voltage response spectroscopy The higher pH10.5 was chosen to facilitate the detection of the benzoic acid degradation intermediates (GC / MS). By comparing the degradation kinetics of benzoic acid and the total organic carbon (TOC) in a single TiO2 photocatalytic system, (GC / MS) and the generation of active radical species (ESR), the specific reaction path and oxidation mechanism of photoelectrocatalytic degradation of benzoic acid were proposed.Hydroxylated benzoic acid was synthesized in the presence of hydroxyl radical and reactive oxygen species Under the combined action of the radicals, it is further oxidized to small molecule acids and CO2 via the diacid containing 6 carbon atoms (cis-1, 2-dicarboxylic acid).