有机碳与水合金属氧化物对反硝化条件下河流沉积层中苯胺降解的影响

采集渭河沉积物及西安某自备井的地下水,沉积物采用逐级分离法处理后,进行厌氧微宇宙实验,研究反硝化条件下河流沉积层中苯胺降解及有机碳与水合金属氧化物的影响.结果表明,硝酸盐为50、300或400mg·L-1,沉积物中的原有或外加的有机碳都对苯胺降解具有抑制作用;去碳沉积物、去碳去金属沉积物实验中,硝酸盐为50mg·L-1时,外加有机碳具有抑制作用,当硝酸盐为300或400 mg·L-1时则有促进作用.去碳沉积物与去碳去金属沉积物的实验发现,无论是否有外加有机碳,水合金属氧化物都对河床沉积层中反硝化条件下苯胺降解具有促进作用.机理分析表明,反硝化条件下,河流沉积层中的微生物以生长代谢的方式利用苯胺,使其降解.苯胺降解经过脱氨基过程.

The effects of organic carbon and hydrous metal oxides on aniline degradation in weihe riverbed sediments under the denitrification condition

Much aniline-wastewater has been released into the environment, and has the water and soil polluted, as well as affects the human activity and human health by several ways. Aniline is harmful and recalcitrant, and its half-life time is about 10 years in anaerobic sediments. It is important to study the degradation of aniline in anaerobic conditions to treat aniline pollution in water and soil. Up to now, research has only been conducted in aerobic condition and little in anaerobic environment. The riverbed sediments from Weihe River, and groundwater from a well in Xi'an were mixed in 1 000 mLbrown bottles. Aniline, nitrate and other reagents were added to the bottles based on the test design, and flushed with N₂ for 8 min. Then the bottles were sealed immediately with rubber stoppers, and microcosms formed in the bottles. The microcosm tests were conducted that the concentrations of aniline, NO₃^- and NH₄⁺ were monitored to research aniline degradation and the effects of organic carbon and hydrous metal oxides on the degradation under denitrification conditions. During the test with nitrate as electron acceptor,the concentration of aniline was stated in microcosms with Na₃ (500 mg·L^-1), and also stated in microcosms with sediments for 30 d, when 50 mg·L^-1 of nitrate has added to the microcosm, the concentrations of aniline and NO₃^- were decreased simultaneously, therefore, aniline degraded by the denitrifers. During the test on the effect of organic carbon on the aniline degradation, when nitrate was 50, 300 or 400 mg·L^-1, the external or internal organic carbon in the sediments inhibited the degradation of aniline. To the sediments removed organic matter and removed both organic matter and hydrous metal oxides, when the nitrate was 50 mg·L^-1, the additive organic carbon enhanced the degradation of aniline. And when the nitrate was 300 or 400 mg·L^-1, the additive organic carbon inhibited the degradation on the contrary. The results of the test on the effect of organic carbon on the aniline degradation showed that, the hydrous metal oxides enhanced the degradation. The aniline was biodegraded by growth metabolism, and deamination was involved in the process.