Relationship between reaction rate constants of organic pollutants and their molecular descriptors during Fenton oxidation and in situ formed ferric-oxyhydroxides

• Published in: Journal of environmental sciences (China) Vol. 43; no. 5; pp. 257 - 264
• Main Authors: Jia, Lijuan, Shen, Zhemin, Su, Pingru
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-05-2016
• Subjects: Bond order; Coagulation; Fenton oxidation; Ferric Compounds - chemistry; Fukui indices; Hydrogen Peroxide - chemistry; Iron; Molecular descriptors; Organic Chemicals - chemistry; Oxidation-Reduction; Studio软件; Water Pollutants, Chemical - chemistry; Water Purification - methods; 三价铁; 分子描述符; 原位; 反应速率常数; 有机化合物; 有机污染物; 氢氧化物; Molecular descriptors; Bond order; Fenton oxidation; Coagulation; Fukui indices
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2015.10.019

Fenton oxidation is a promising water treatment method to degrade organic pollutants. In this study, 30 different organic compounds were selected and their reaction rate constants（k） were determined for the Fenton oxidation process. Gaussian09 and Material Studio software sets were used to carry out calculations and obtain values of 10 different molecular descriptors for each studied compound. Ferric-oxyhydroxide coagulation experiments were conducted to determine the coagulation percentage. Based upon the adsorption capacity,all of the investigated organic compounds were divided into two groups（Group A and Group B）. The percentage adsorption of organic compounds in Group A was less than 15%（wt./wt.）and that in the Group B was higher than 15%（wt./wt.）. For Group A, removal of the compounds by oxidation was the dominant process while for Group B, removal by both oxidation and coagulation（as a synergistic process） took place. Results showed that the relationship between the rate constants（k values） and the molecular descriptors of Group A was more pronounced than for Group B compounds. For the oxidation-dominated process,EHOMOand Fukui indices（f（0）_x, f（-）_x, f（＋）_x） were the most significant factors. The influence of bond order was more significant for the synergistic process of oxidation and coagulation than for the oxidation-dominated process. The influences of all other molecular descriptors on the synergistic process were weaker than on the oxidation-dominated process.