POPs Research Center, School of Environment, Tsinghua University, Beijing, PR China.
Chemosphere. 2012 May;87(9):1032-8. doi: 10.1016/j.chemosphere.2012.01.004. Epub 2012 Jan 26.
Pentachlorobenzene (PeCB) in simulated flue gas was destructed by a commercial V(2)O(5)-WO(3)/TiO(2) catalyst in this study. The effects of reaction temperature, oxygen concentration, space velocity and some co-existing pollutants on PeCB conversion were investigated. Furthermore, a possible mechanism for the oxidation of PeCB over the vanadium oxide on the catalysts was proposed. Results show that the increase of gas hourly space velocity (GHSV) and the decrease of operating temperature both resulted in the decrease of PeCB removal over the catalyst, while the effect of the oxygen content in the range of 5-20% (v/v) on PeCB conversion was negligible. PeCB decomposition could be obviously affected by the denitration reactions under the conditions because of the positive effect of NO but negative effect of NH(3). The introduction of SO(2) caused the catalyst poisoning, probably due to the sulfur-containing species formed and deposited on the catalyst surface. The PeCB molecules were first adsorbed on the catalyst surface, and then oxidized into the non-aromatic acyclic intermediates, low chlorinated aromatics and maleic anhydride.
五氯苯(PeCB)在模拟烟道气中被一种商业 V(2)O(5)-WO(3)/TiO(2) 催化剂所破坏。研究考察了反应温度、氧浓度、空速和一些共存污染物对 PeCB 转化率的影响。此外,还提出了在催化剂上的氧化钒催化 PeCB 氧化的可能机理。结果表明,增加气体时空间速度(GHSV)和降低操作温度都会导致催化剂上 PeCB 去除率降低,而在 5-20%(v/v)范围内的氧含量对 PeCB 转化率的影响可以忽略不计。由于 NO 的正效应和 NH(3)的负效应,在条件下,脱硝反应会明显影响 PeCB 的分解。SO(2)的引入会导致催化剂中毒,这可能是由于形成和沉积在催化剂表面的含硫物种所致。PeCB 分子首先被吸附在催化剂表面,然后被氧化成非芳香无环中间体、低氯代芳烃和马来酸酐。