催化湿式过氧化氢氧化苯酚的诱导期研究

针对诱导期发生机制及影响因素尚不清楚问题，采用自制化学反应装置和批动力学试验方法，研究了黏土基催化剂催化过氧化氢（H₂O₂）氧化苯酚过程中诱导期发生的原因及其关键影响因子。结果表明：H₂O₂扩散或吸附到催化剂金属活性位及随后的表面修饰（通过≡Fe（III）还原到≡Fe（II）降低pH）共同决定了诱导期；Fermi’s方程能很好地拟合苯酚氧化过程（R²>0.99）；反应温度和溶液pH强烈影响诱导时间（t_I），随温度增加和pH降低，t_I分别从59和129 min降到22和0 min（没有诱导期），而催化剂与H₂O₂用量对t_I的影响相对较小，随催化剂和H₂O₂浓度增加，t_I分别从69和75 min降到32和52 min。尽管诱导时间可通过调整反应参数缩短或消除，但考虑到成本和环境风险，在用黏土基催化剂处理实际含酚废水时应采纳适宜的反应条件：H₂O₂和苯酚质量浓度摩尔比为15，催化剂浓度为0.8~1.0
g/L，温度为30~40 °C，介质pH（不调整），反应时间为2 h。

Study on Induction Period during Catalytic Wet Peroxide Oxidation of Phenol

Aiming at improving the understanding of occurrence mechanism and affecting factors of induction period, a small laboratory-made reactor with batch kinetic test method was adopted to investigate the induction period occurrence reasons and the key affecting factors during phenol oxidation by H2O2 over clay-based catalysts. The results showed that the contact of active metals with H2O2 and the sequent surface modification, by decreasing pH via the reduction of ≡Fe (III) to ≡Fe (II), jointly determined the induction period. A Fermi’s equation could fit well the kinetic process (R2 > 0.99), and the reaction temperature and initial solution pH strongly affected the induction time (tI) which reduced from 59 min to 22 min and from 129 min to 0 min (no induction period), respectively, with increasing temperature and decreasing pH. The catalyst amount and H2O2 concentration had less effect on tI which reduced from 69 to 32 min and from 75 to 52 min, respectively, with increasing the contents of catalyst and H2O2. Although the undesirable induction time could be shortened or eliminated by adjusting reaction parameters, considering its cost and environmental risk, the following optimum reaction conditions should be adopted for CWPO of actual phenol-containing wastewater over clay-based catalysts: the mole ratio of H2O2 to phenol being 15, catalyst concentration being 0.8-1.0 g/L, temperature being 30-40 °C, pH of matrix not adjusted, and reaction time being 2 h.