摘要
为了研究纳米TiO2对底泥汞的释放及活化的影响,采用模拟淹水实验,分析纳米TiO2对底泥和上覆水中总汞和甲基汞浓度的影响,并结合底泥中各形态汞的变化情况探讨纳米TiO2对汞的迁移转化的影响.结果表明,纳米TiO2可促进底泥中汞的释放,导致更多的汞释放到水中,与对照相比,4g·kg-1纳米TiO2导致上覆水中总汞浓度最高时上升91.32%,最终土壤汞的释放量增加约10%,主要原因是纳米TiO2可促进氧化态汞的溶解,这可能会提高水体汞污染的风险.此外,在本实验条件下,短期内纳米TiO2可能降低了底泥甲基汞的形成和释放,但长期淹水后没有明显的影响.总体来看,纳米TiO2对底泥汞释放和转化的影响随浓度升高而增大.因此,随着底泥或土壤中纳米TiO2含量的升高,其对汞的地球化学循环过程的影响可能加剧.
To investigate the effects of nano-TiO2 on mercury release and activation in sediment,flooding simulation experiments were conducted. The impacts of nano-TiO2 on total mercury and methylmercury concentrations in overlying water were analyzed. And the influences of nano-TiO2 on the migration and transformation of mercury were discussed based on changes of mercury speciation in sediment. The results indicated that nano-TiO2 promoted the release of mercury in sediment,leading to more mercury released into the water. Compared with the control,4 g·kg- 1TiO2 nanoparticles increased the total mercury by 91. 32%,when the concentration of total mercury in overlying water was the highest. Release of mercury in soil was increased by approximately 10% finally. The main reason may be that the dissolution of oxidation state mercury was improved by nano-TiO2. It indicated that the risk of mercury contamination in water may increase. Moreover,under the experimental conditions,nano-TiO2 may reduce the formation of methylmercury in sediment in the short term,but no significant effects in the long term. Generally,the effects of nano-TiO2 on the release and transformation of mercury in sediment showed concentration dependence. Thus,with increasing nano-TiO2 content in sediment or soil,its impact on the geochemical cycle of mercury may increase.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2014年第12期4567-4572,共6页
Environmental Science
基金
国家重点基础研究发展规划(973)项目(2013CB430004)
国家自然科学基金项目(41173116)
四川省教育厅项目(13ZB0004)
