亚甲基蓝芬顿氧化脱色的动力学和热力学研究

Kinetic and thermodynamic studies of fenton oxidative decolorization of methylene blue.

作者信息

Giwa Abdur-Rahim A, Bello Isah A, Olabintan Abdullahi B, Bello Olugbenga S, Saleh Tawfik A

机构信息

Department of Pure and Applied Chemistry, LadokeAkintola University of Technology, P. M. B., 4000, Ogbomoso, Oyo State, Nigeria.

Chemistry Department, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.

出版信息

Heliyon. 2020 Aug 26;6(8):e04454. doi: 10.1016/j.heliyon.2020.e04454. eCollection 2020 Aug.

The need for light intensity has made dye degradation very costly for industry. In this work, Fenton reagent was used for the efficient degradation of an aqueous solution of dye without the need for a light source. The influences of the pH of the media, the initial concentrations of Fe, HO, and methylene blue (MB) dye; in addition to temperature on the oxidation of MB dye were studied. The optimum amounts of the Fenton reagent were 4mM of Fe and 70mM of HO at 20 mg/L of dye. The optimum ratio of 0.05 of Fe/HO was found to give the best result for the decolorization of dye. The Fenton process was effective at pH 3 with a maximum dye decolorization efficiency of 98.8% within 30 min of reaction, corresponding to a COD removal of 85%. The decolorization process was thermodynamically feasible, spontaneous, and endothermic. The activation energy (E) was 33.6 kJ/mol suggesting that the degradation reaction proceeded with a low energy barrier.

对光强度的需求使得染料降解对工业来说成本非常高昂。在这项工作中，使用芬顿试剂在无需光源的情况下对染料水溶液进行高效降解。研究了介质的pH值、铁（Fe）、过氧化氢（HO）和亚甲基蓝（MB）染料的初始浓度，以及温度对MB染料氧化的影响。在染料浓度为20 mg/L时，芬顿试剂的最佳用量为4 mM的Fe和70 mM的HO。发现Fe/HO的最佳比例为0.05时，染料脱色效果最佳。芬顿工艺在pH值为3时有效，在反应30分钟内染料脱色效率最高可达98.8%，对应的化学需氧量（COD）去除率为85%。脱色过程在热力学上是可行的、自发的且吸热的。活化能（E）为33.6 kJ/mol，表明降解反应以低能垒进行。