Fukushima M, Tatsumi K
National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba 305-8569, Japan.
Environ Sci Technol. 2001 May 1;35(9):1771-8. doi: 10.1021/es001088j.
The degradation characteristics and pathways of pentachlorophenol (PCP) by the photo-Fenton systems were studied in H2O2 aqueous solutions, which contained Fe(III) only [H2O2/Fe(III) system] and Fe(III) + humic acid (HA) [H2O2/Fe(III)/HA system] at pH 5.0. Although 40% of the PCP was degraded after 5 h of irradiation in the H2O2/Fe(III) system, more than 90% was degraded in the H2O2/Fe(III)/HA system. This shows that at pH 5.0 the degradation of PCP is clearly enhanced by the presence of HA in the photo-Fenton system. In the H2O2/Fe(III) system, the production of octachlorodibenzo-p-dioxin (OCDD) was detected, and 2-hydroxy nonachlorodiphenyl ether was also identified as a precursor of OCDD. However, no OCDD production was observed in the H2O2/Fe(III)/HA system. This indicates that the presence of HA represses the production of OCDD during the degradation of PCP by the photo-Fenton system. Such an effect by HA can be attributed to a reaction sequence wherein reaction intermediates derived from PCP, such as PCP., are incorporated into HA. This was verified by 13C NMR and pyrolysis-GC/MS studies.
在pH值为5.0的过氧化氢水溶液中，研究了光芬顿体系对五氯苯酚（PCP）的降解特性及途径，该体系包含仅含Fe(III)的[H2O2/Fe(III)体系]和Fe(III) + 腐殖酸（HA）的[H2O2/Fe(III)/HA体系]。尽管在H2O2/Fe(III)体系中照射5小时后40%的PCP被降解，但在H2O2/Fe(III)/HA体系中超过90%的PCP被降解。这表明在pH值为5.0时，光芬顿体系中HA的存在明显增强了PCP的降解。在H2O2/Fe(III)体系中，检测到八氯二苯并对二噁英（OCDD）的生成，并且2-羟基九氯二苯醚也被鉴定为OCDD的前体。然而，在H2O2/Fe(III)/HA体系中未观察到OCDD的生成。这表明HA的存在抑制了光芬顿体系降解PCP过程中OCDD的生成。HA的这种作用可归因于一个反应序列，其中PCP衍生的反应中间体，如PCP·，被并入HA中。这通过13C NMR和热解-气相色谱/质谱研究得到了验证。
