Yang Xiaofang, He Jie, Sun Zhongxi, Holmgren Allan, Wang Dongsheng
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Environ Sci (China). 2016 Jan;39:69-76. doi: 10.1016/j.jes.2015.11.007. Epub 2015 Dec 21.
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-Fe3O4 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.
研究了磷酸盐对非均相芬顿体系中邻苯二酚（1,2 - 二羟基苯）吸附和氧化的影响。采用原位衰减全反射红外光谱（ATR - FTIR）监测纳米Fe3O4催化剂表面的表面物种形成情况。磷酸盐的存在降低了邻苯二酚的去除率、溶解有机化合物的去除率以及H2O2的分解率。磷酸盐的这种影响主要是由于其与氧化铁催化剂表面位点的强烈反应。在中性和酸性pH条件下，磷酸盐可以将吸附在催化剂表面的邻苯二酚置换出来，并且还能与H2O2竞争表面位点。原位红外光谱表明在催化剂表面形成了磷酸铁沉淀。磷酸铁表面物种可能会影响参与H2O2催化分解和羟基自由基形成的铁原子数量，并抑制Fe3O4催化剂的催化能力。因此，在本研究中，磷酸盐离子在非均相芬顿反应中同时起到了稳定剂和抑制剂的作用，实际上导致了氧化效率的提高。然而，在非均相芬顿体系中使用磷酸盐作为pH缓冲剂或H2O2稳定剂之前，应充分考虑磷酸盐对有机污染物实际去除的可能抑制作用。
