He Di, Guan Xiaohong, Ma Jun, Yu Min
State Key Lab of Urban Water Resource and Environment (HIT), Harbin Institute of Technology, Harbin, P. R. China.
Environ Sci Technol. 2009 Nov 1;43(21):8332-7. doi: 10.1021/es901700m.
The effects of humic acid (HA) and its different nominal molecular weight (NMW) fractions on the phenol oxidation by permanganate were studied. Phenol oxidation by permanganate was enhanced by the presence of HA at pH 4-8, while slightly inhibited at pH 9-10. The effects of HA on phenol oxidation by permanganate were dependent on HA concentration and permanganate/phenol molar ratios. The high NMW fractions of HA enhanced phenol oxidation by permanganate at pH 7 more significantly than the low fractions of HA. The apparent second-order rate constants of phenol oxidation by permanganate in the presence of HA correlated well with their specific ultraviolet absorption (SUVA) at 254 nm and specific violet absorption (SVA) at 465 or 665 nm. High positive correlation coefficients (R(2) > 0.72) implied that pi-electrons of HA strongly influenced the reactivity of phenol towards permanganate oxidation which agreed well with the information provided by fluorescence spectroscopy. The FTIR analysis indicated that the HA fractions rich in aliphatic character, polysaccharide-like substances, and the amount of carboxylate groups had less effect on phenol oxidation by permanganate. The negative correlation between the rate constants of phenol oxidation by permanganate and O/C ratios suggested that the oxidation of phenol increased with a decrease in the content of oxygen-containing functional groups.
研究了腐殖酸（HA）及其不同标称分子量（NMW）组分对高锰酸盐氧化苯酚的影响。在pH 4 - 8时，HA的存在增强了高锰酸盐对苯酚的氧化作用，而在pH 9 - 10时略有抑制。HA对高锰酸盐氧化苯酚的影响取决于HA浓度和高锰酸盐/苯酚摩尔比。在pH 7时，HA的高分子量组分比低分子量组分更显著地增强了高锰酸盐对苯酚的氧化作用。在HA存在下，高锰酸盐氧化苯酚的表观二级反应速率常数与其在254 nm处的特定紫外吸收（SUVA）以及在465或665 nm处的特定可见吸收（SVA）具有良好的相关性。高正相关系数（R(2) > 0.72）表明，HA的π电子强烈影响苯酚对高锰酸盐氧化的反应活性，这与荧光光谱提供的信息一致。傅里叶变换红外光谱（FTIR）分析表明，富含脂肪族特征、类多糖物质以及羧基含量的HA组分对高锰酸盐氧化苯酚的影响较小。高锰酸盐氧化苯酚的反应速率常数与O/C比之间的负相关表明，苯酚的氧化随着含氧官能团含量的降低而增加。
