载氧沸石对沉积物-水剖面氮去除的机制
The mechanism of nitrogen migration aceoss sediment-water core manipulated by oxygen-loaded zeolite
杨兵 1罗竣潇 2唐炳然 3邓联军 2葛淼 4刘强 4张晓岭 4何强 3李宏3
作者信息
- 1. 重庆大学,三峡库区生态环境教育部重点实验室,重庆 400045;重庆市生态环境监测中心,重庆 401147
- 2. 中国建筑第五工程局有限公司,湖南 长沙 410004
- 3. 重庆大学,三峡库区生态环境教育部重点实验室,重庆 400045
- 4. 重庆市生态环境监测中心,重庆 401147
- 折叠
摘要
以 3 种粉煤灰为原材料,制备了粉煤灰基载氧沸石,通过构建原位沉积物柱试验体系,探究了覆盖厚度为 0.5,1.0 和 2.0cm的粉煤灰基载氧沸石对沉积物-水剖面氮的去除效果与机制.结果表明,粉煤灰基载氧沸石能通过吸附和释氧作用降低沉积物-水体系中的氮含量,并控制沉积物中氮的释放,改善效果与材料覆盖厚度正相关.覆盖 25d后,0.5,1.0,2.0cm覆盖厚度处理组中沉积物-水界面处的溶解氧浓度分别为 1.79,3.69,6.26mg/L,上覆水中总氮的去除率分别为22.77%､30.37%和39.10%,沉积物中氨氮释放通量相较于对照组分别削减了31.4%､47.00%和50.47%.此外,粉煤灰基载氧沸石提高了沉积物表层中参与硝化和反硝化作用的微生物丰度,并增加了硝化功能基因(amoA),反硝化功能基因(narG､napA､nirS和nirK)和好氧反硝化基因(napA)的丰度,表明在表面沉积物中发生了耦合的有氧-缺氧反硝化过程.研究结果有望为粉煤灰的资源化利用和水体内源污染治理提供新的视角.
Abstract
Dissolved oxygen is essential for the migration of nitrogen in the sediment.In this study,we prepared oxygen-loaded zeolite using three kinds of fly ash,then explored the removal efficiency and mechanisms toward nitrogen in sediment-water systems by capping the surface sediment with the oxygen-loaded zeolite(with thicknesses of 0.5,1.0,and 2.0cm).The results showed that the oxygen-loaded zeolite was able to reduce the nitrogen content in the sediment-water system and control the release of nitrogen from the sediment through the adsorption and oxygen release,and the effect is positively correlated with the thickness of the capping materials.The dissolved oxygen concentrations at the sediment-water interface in the 0.5,1.0,and 2.0cm thickness treatment groups reached 1.79,3.69,and 6.26mg/L after 25 days of incubation,respectively.Meanwhile,the removal rate of total nitrogen in the overlying water was 22.77%in the 0.5cm thickness group,30.37%in the 1cm thickness group,and 39.10%in the 2cm thickness group.Compared with the control group,the ammonia release flux across the sediment-water interface was reduced by 31.4%,47.0%,and 50.47%,respectively.In addition,the oxygen-loaded zeolite increased the abundance of microorganisms involved in nitrification and denitrification.The abundance of nitrification functional genes(amoA),denitrification functional genes(narG,napA,nirS,and nirK),and aerobic denitrification genes(napA)in the surface sediments was substantially promoted,demonstrating that a coupled aerobic-anoxic denitrification process may occur in the surface sediments.The results from this study may provide a new perspective for the utilization of fly ash and management of the international nutrients loading.
关键词
载氧沸石/覆盖/沉积物/内源污染/好氧反硝化Key words
fly ash-based zeolite/capping/sediment/international nutrients loading/aerobic denitrification引用本文复制引用
基金项目
国家自然科学基金资助项目(52370199)
重庆市自然科学基金资助项目(cstc2021jcyjmsxmX1199)
重庆市技术创新与应用发展专项(CSTB2022TIAD-GPX0076)
出版年
2024
NETL
NSTL
万方数据