腐植酸对水溶液中丁草胺光化学降解的影响

采用紫外光照射的方法研究了腐植酸对丁草胺光降解特性的影响。结果表明，潮土腐植酸对丁草胺的光降解具有明显的抑制。潮土腐植酸浓度较低（〈10mg·L^-1）时，随腐植酸浓度的增加，对丁草胺光降解的抑制作用越强，丁草胺光降解速率越低；当潮土腐植酸的浓度≥10mg·L^-1时，腐植酸浓度的变化对丁草胺光降解的抑制作用影响不大，20mg·L^-1腐植酸与10mg·L^-1腐植酸对丁草胺光降解的影响相近。不同腐植酸对丁草胺光降解的抑制作用不同，商品腐植酸对丁草胺光降解抑制作用较强，潮土腐植酸和黑土腐植酸对丁草胺光降解的抑制作用则相对较弱。这种现象可能是由腐植酸的纯度和腐植酸本身结构特性的差异造成的。

Effects of Humic Acid Substances on Photodegradation of Butachlor in Waters

The herbicide butachlor, N- （butoxymethyl）-2-chloro-2, 6-diethyl acetanilide, is one of the three main herbicides used to control weeds in China. Because of its toxicity to ecological systems and persistence in environments, the fate of butachlor in environments is of great concern to many environmental scientists. In this work, effects of humic acid substances （HAS） on photodegradation of butaehlor in waters were investigated through laboratory experiments under the conditions of UV irradiation. Three kinds of HAS i.e. fluvo-aquie HAS extracted from alluvial soils, phaeozem HAS extracted from wet plain soils and commercial HAS were used for the experiments to investigate the inhibiting effects on bntachlor photodegradation. The experimental results showed that the three HASs inhibit the photodegradation of hutachlor in waters and the commercial HAS has the strongest effect. The fluvo-aquic HAS had an obvious inhibiting effect on photodegradation of bntachlor increasing with its concentration in a certain range （0- 10 mg·L^-1）, beyond 10 mg·L^-1, the inhibiting effe ct Would not increased with the concentration of HAS. The different inhibiting effects with the three HASs could be explained with the difference of their structural characteristics studied using Fourier Transform Infrared-spectroscopy （FTIR） in this work. The FTIR spectra showed that the flu vo-aquic HAS and phaeozem HAS were similar in structure different from that of the commercial HAS.