Effect of phosphate on heterogeneous Fenton oxidation of catechol by nano-Fe_(3)O_(4):Inhibitor or stabilizer?  

作　　者：Xiaofang Yang Jie He Zhongxi Sun Allan Holmgren Dongsheng Wang 

机构地区：[1]Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]School of Chemistry and Chemical Engineering,University of Jinan,Jinan 250022,China [4]Chemical Engineering,Department of Civil,Environmental and Natural Resources Engineering,Lulea University of Technology,SE-971 87,Sweden

出　　处：《Journal of Environmental Sciences》2016年第1期69-76,共8页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.21107125,21577160,51290282,51221892);the National Basic Research Program(973s)of China(No.2011CB933704);the Hjalmar Lundbom Research Center at Lulea niversity of Technology

摘　　要：The effect of phosphate on adsorption and oxidation of catechol, 1,2-dihydroxybenzene,in a heterogeneous Fenton system was investigated. In situ attenuated total reflectance infrared spectroscopy（ATR-FTIR） was used to monitor the surface speciation at the nano-Fe_3O_4 catalyst surface. The presence of phosphate decreased the removal rate of catechol and the abatement of dissolved organic compounds, as well as the decomposition of H2O2. This effect of phosphate was mainly due to its strong reaction with surface sites on the iron oxide catalyst. At neutral and acid pH, phosphate could displace the adsorbed catechol from the surface of catalyst and also could compete for surface sites with H2O2. In situ IR spectra indicated the formation of iron phosphate precipitation at the catalyst surface. The iron phosphate surface species may affect the amount of iron atoms taking part in the catalytic decomposition of H2O2 and formation of hydroxyl radicals,and inhibit the catalytic ability of Fe3O4 catalyst. Therefore, phosphate ions worked as stabilizer and inhibitor in a heterogeneous Fenton reaction at the same time, in effect leading to an increase in oxidation efficiency in this study. However, before use of phosphate as pH buffer or H2O2 stabilizer in a heterogeneous Fenton system, the possible inhibitory effect of phosphate on the actual removal of organic pollutants should be fully considered.The effect of phosphate on adsorption and oxidation of catechol, 1,2-dihydroxybenzene,in a heterogeneous Fenton system was investigated. In situ attenuated total reflectance infrared spectroscopy（ATR-FTIR） was used to monitor the surface speciation at the nano-Fe_3O_4 catalyst surface. The presence of phosphate decreased the removal rate of catechol and the abatement of dissolved organic compounds, as well as the decomposition of H2O2. This effect of phosphate was mainly due to its strong reaction with surface sites on the iron oxide catalyst. At neutral and acid pH, phosphate could displace the adsorbed catechol from the surface of catalyst and also could compete for surface sites with H2O2. In situ IR spectra indicated the formation of iron phosphate precipitation at the catalyst surface. The iron phosphate surface species may affect the amount of iron atoms taking part in the catalytic decomposition of H2O2 and formation of hydroxyl radicals,and inhibit the catalytic ability of Fe3O4 catalyst. Therefore, phosphate ions worked as stabilizer and inhibitor in a heterogeneous Fenton reaction at the same time, in effect leading to an increase in oxidation efficiency in this study. However, before use of phosphate as pH buffer or H2O2 stabilizer in a heterogeneous Fenton system, the possible inhibitory effect of phosphate on the actual removal of organic pollutants should be fully considered.

关 键 词：Heterogeneous Fenton oxidation Adsorption ATR-FTIR Interface mechanism 

分 类 号：X505[环境科学与工程—环境工程] TQ426[化学工程]