当前位置: X-MOL 学术Catal. Today › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Rapid oxidation of paracetamol by Cobalt(II) catalyzed sulfite at alkaline pH
Catalysis Today ( IF 5.2 ) Pub Date : 2017-12-15 , DOI: 10.1016/j.cattod.2017.12.004
Yanan Yuan , Dan Zhao , Jinjun Li , Feng Wu , Marcello Brigante , Gilles Mailhot

In this study we have investigated the efficiency Cobalt (II) (Co(II)) for the activation of sulfite ions following the oxidation of paracetamol used as model contaminants. Physico-chemical parameters that can impact the paracetamol degradation (pH, initial paracetamol concentration, Co(II)/S(IV) molar ratio, oxygen concentration) and contribution of various radicals were investigated in order to elucidate the chemical mechanism. Main results show that the pH is a key factor controlling the efficiency in the system Co(II)/Sulfite. Higher efficiency is observed for pH between 9.0 and 10.0. Increasing S(IV) concentrations, until 1 mM, slightly promoted the degradation of paracetamol. In fact, an excess of sulfite ions inhibits the reaction through the scavenging of SO4 and SO5. Moreover, degradation efficiency drastically decreases from ∼ 85% to less than 5% in absence of oxygen. SO4 was confirmed to be the main oxidant responsible for the paracetamol degradation. For the first time we determined the second order rate constant between SO4 and paracetamol (1.33 ± 0.79 × 109 M−1 s−1 (at pH 5) and 6.14 ± 0.99 × 108 M−1 s−1 (at pH 11.0)). Moreover, radical-scavenging experiments also suggest the possible implication of SO5. Hence, this work provides a precise understanding of the overall mechanism and a new promising strategy by using sulfite and transition metal such as Co(II) to promote organic compounds degradation in water under neutral and alkaline pH conditions.



中文翻译:

钴(II)催化的亚硫酸盐在碱性pH下快速氧化对乙酰氨基酚

在这项研究中,我们研究了用作模型污染物的扑热息痛氧化后,钴(II)(Co(II))活化亚硫酸根离子的效率。为了阐明化学机理,研究了可能影响扑热息痛降解的理化参数(pH,扑热息痛初始浓度,Co(II)/ S(IV)摩尔比,氧浓度)和各种自由基的贡献。主要结果表明,pH是控制Co(II)/亚硫酸盐体系效率的关键因素。在9.0和10.0之间的pH值下观察到更高的效率。增加S(IV)浓度直至1 mM会轻微促进对乙酰氨基酚的降解。实际上,过量的亚硫酸根离子抑制通过SO的清除反应4 -和SO 5-。而且,在没有氧气的情况下,降解效率从约85%急剧降低到5%以下。SO 4 -被证实为负责的对乙酰氨基酚降解的主要氧化剂。首次我们测定SO之间的二级速率常数4 -和对乙酰氨基酚(1.33±0.79×10 9 中号-1 小号-1(在pH 5)和6.14±0.99×10 8 中号-1 小号-1(在pH 11.0))。此外,清除自由基的实验也表明SO的可能产生的影响5 -。因此,这项工作通过使用亚硫酸盐和过渡金属(例如Co(II))来促进有机化合物在中性和碱性pH条件下在水中的降解,从而提供了对整体机理的精确理解和新的有希望的策略。

更新日期:2017-12-15
down
wechat
bug