| 硝酸根对水体中甲基汞光化学降解的影响 |
| 摘要点击 3320 全文点击 1818 投稿时间：2012-09-04 修订日期：2012-11-30 |
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| 中文关键词 甲基汞 光化学降解 硝酸根 羟基自由基 反应历程 光照条件 |
| 英文关键词 monomethylmercury photodecomposition nitrate hydroxyl radical react process light condition |
| 作者 | 单位 | E-mail | | 毛雯 | 西南大学资源环境学院,三峡库区生态环境教育部重点实验室,重庆 400715 | maowenqj@163.com | | 孙荣国 | 西南大学资源环境学院,三峡库区生态环境教育部重点实验室,重庆 400715 | | | 王定勇 | 西南大学资源环境学院,三峡库区生态环境教育部重点实验室,重庆 400715
重庆市农业资源与环境研究重点实验室,重庆 400716 | dywang@swu.edu.cn | | 马明 | 西南大学资源环境学院,三峡库区生态环境教育部重点实验室,重庆 400715 | | | 张成 | 西南大学资源环境学院,三峡库区生态环境教育部重点实验室,重庆 400715 | |
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| 中文摘要 |
| 为研究硝酸根(NO3-)对水体中甲基汞(MMHg)光化学降解的影响,采用室内模拟试验,验证了不同波长光照条件下,NO3-在MMHg光化学反应中的作用,探讨了NO3-浓度对MMHg光解速率及产物的影响,并根据溶液中Hg2+的浓度分析了MMHg光解反应的进行程度. 结果表明,在自然光(NL)和紫外光(UV)条件下,只加入了NO3-的处理MMHg光降解速率分别为0.10、0.046 L·(ng·h)-1,Hg0的释放通量分别为1.05、1.27 ng,Hg2+的最终浓度分别为16.97、28.92 ng·L-1; 在未加入NO3-和加入了C6H5COOH的条件下,MMHg的剩余浓度相差不大,其光降解速率也分别在0.052、0.015 L·(ng·h)-1左右,Hg0的释放通量分别为23.81、15.38 ng,Hg2+的浓度均小于10 ng·L-1,且呈现先增加后减小趋势. 在可见光(VL)照射下,各处理下MMHg的光降解速率无显著性差异(P=0.56),为0.003 L·(ng·h)-1左右,Hg0的释放通量均为5 ng左右,Hg2+的浓度未超过3 ng·L-1,也呈现出先增加后减小的趋势. 在NL条件下,随浓度NO3-的增加,MMHg的光降解速率也增加,且各处理间存在显著性差异(P<0.05),Hg0的生成量随NO3-浓度的增加而减少,而Hg2+的浓度也随NO3-浓度的增加而增加. 可见在有紫外光的条件下,NO3-对MMHg光降解反应历程、反应速率以及产物有重要影响. |
| 英文摘要 |
| To study effects of nitrate (NO3-) on monomethylmercury (MMHg) photodecomposition (PD), laboratory experiments were conducted to investigate the role of NO3- in MMHg PD under various light radiations, and to examine effects of NO3- concentration gradients on MMHg PD rates and end products. We analysed the react processes according to Hg2+ concentration. The results indicated that in the reactor exposed to natural and ultraviolet radiation, and treated with NO3-, the rates of MMHg PD were calculated to be 0.10 L·(ng·h)-1 and 0.046 L·(ng·h)-1, respectively, Hg0 fluxes were 1.05 and 1.27 ng, respectively, and Hg2+concentrations were 16.97 ng·L-1 and 28.92 ng·L-1 respectively. In the experiments which were not spiked with nitrate or spiked with benzoic acid, MMHg PD rates were calculated to be 0.052 L·(ng·h)-1 and 0.015 L·(ng·h)-1, respectively, Hg0 fluxes were 23.81 ng and 15.38 ng, respectively, and all concentrations of Hg2+ (<10 ng·L-1) represented a trend of increasing firstly and then decreasing. There were no differences among the reactions exposed to visible light (P=0.56), the PD rate was about 0.003 L·(ng·h)-1, Hg0 flux was about 5 ng, and Hg2+ concentrations showed a trend of increasing firstly and then decreasing. In the reactor exposed to natural light, with the increasing concentration of NO3-, MMHg PD rate increased, Hg0 flux decreased, and Hg2+ concentration increased with respect to time. All results indicate that NO3- has a significant effect on the react process, PD rate, and end products. |
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