Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024, PR China.
J Hazard Mater. 2011 Nov 15;195:276-80. doi: 10.1016/j.jhazmat.2011.08.041. Epub 2011 Sep 10.
A pulsed discharge plasma-TiO(2) catalytic (PDPTC) system was developed to investigate the degradation of p-nitrophenol (PNP) in soil. The effects of TiO(2) amount, soil pH and air moisture on PNP degradation were evaluated, and PNP degradation processes were predicted with Gaussian 03W combined with density functional theory (DFT). Experimental results showed that 88.8% of PNP could be smoothly removed in 10 min in the PDPTC system with the specific energy density of 694 J g(soil)(-1), compared with 78.1% in plasma alone system. The optimum TiO(2) amount was 2% in the present study, and higher TiO(2) amount exhibited an inhibitive effect. Alkaline soil was favorable for PNP removal. The increase of air moisture to a certain extent could enhance PNP removal. A DFT calculation presented that there was a high preference for the -ortho and -para positions with respect to the functional -OH group of PNP molecule for OH radicals attack. The main intermediates were hydroquinone, benzoquinone, catechol, phenol, benzo[d][1,2,3]trioxole, acetic acid, formic acid, NO(2)(-), NO(3)(-) and oxalic acid. The generation of hydroxylated intermediates, NO(2)(-) and NO(3)(-) suggested that the experimental results were consistent with those of the theoretical prediction.
开发了一种脉冲放电等离子体-TiO(2)催化（PDPTC）系统，以研究土壤中对硝基苯酚（PNP）的降解。评估了 TiO(2)量、土壤 pH 和空气湿度对 PNP 降解的影响，并使用 Gaussian 03W 结合密度泛函理论（DFT）对 PNP 降解过程进行了预测。实验结果表明，在特定能量密度为 694 J g(soil)(-1)的 PDPTC 系统中，PNP 可在 10 分钟内顺利去除 88.8%，而在单独的等离子体系统中为 78.1%。本研究中最佳的 TiO(2)用量为 2%，更高的 TiO(2)用量表现出抑制作用。碱性土壤有利于 PNP 的去除。空气湿度的增加在一定程度上可以增强 PNP 的去除。DFT 计算表明，对于 PNP 分子的功能-OH 基团，OH 自由基攻击更倾向于对位和邻位。主要的中间产物是对苯二酚、邻苯二醌、儿茶酚、苯酚、苯并[d][1,2,3]三唑、乙酸、甲酸、NO(2)(-)、NO(3)(-)和草酸。羟基化中间产物、NO(2)(-)和 NO(3)(-)的生成表明实验结果与理论预测一致。
