湿式氧化催化剂RuO_2/γ-Al_2O_3的制备及降解苯酚的研究

Preparation of RuO_2/γ-Al_2O_3 Catalysts and Study on Catalytic Wet Air Oxidation of Phenol

采用浸渍法制备了 4 %质量分数的RuO2 /γ Al2 O3 催化剂 ,并利用XRD和SEM对催化剂进行了晶体结构表征。研究了催化剂制备的焙烧温度和时间、进水pH值和处理温度对RuO2 /γ Al2 O3 催化剂活性影响 ,并对其影响机制进行了初步探讨。结果表明 ,焙烧温度升高、焙烧时间延长会导致催化剂的活性组分RuO2 的晶粒增长过大 ;在 30 0℃经 3h焙烧 ,形成的RuO2 晶粒细小 ,苯酚溶液的COD(化学需氧量 )去除率较高。在本研究的pH范围内 ,进水pH值为酸性时 ,COD去除率高于碱性时的COD去除率 ;当反应温度升高时 ,RuO2 /γ Al2 O3 催化剂降解苯酚的能力显著提高 ,且反应的诱导期明显缩短 ,当反应温度从 15 0℃升高至 180℃时 ,在进水pH值为 5 .6 ,反应 2h后 ,此催化剂的COD去除率为 96 %以上。研究表明 ,RuO2 /γ Al2 O3 催化剂具有较好的活性和和稳定性。

wt% RuO 2/γ-Al 2O 3 was prepared by impregnating Al 2O 3 into aqueous solution composed of RuCl 3·3H 2O.XRD and SEM were used to determine the catalytic structure of the catalysts.Influences of the calcination temperature and time,the initial pH of the feed solution and degradation temperature on the activity of the RuO 2/γ-Al 2O 3 catalyst were investigated and the mechanism was preliminarily studied.The results show that some large RuO 2 crystallites are present in the catalyst surface when the calcination temperature and time increase respectively.A kind of available RuO 2 crystallites with the high COD (Chemical Oxygen Demand) removal were obtained when the catalyst was calcined at 300℃ for 3h.The COD removal for the acid feed solution is much higher than that for the alkaline feed solution.The activity of the catalyst is evidently increased and the induction period is shortened with the increase of reaction temperature,the COD removal is increased from 80% to 96% when the temperature increases from 150℃ to 180℃ at the initial pH of 5.6.The results indicate that RuO 2/Al 2O 3 catalyst has better activity and stability.