缓释氧复合材料不同投加方式对沉积物-水界面污染物迁移的影响

为改善湖泊沉积物-水界面生境,开发了一种可原位供氧同时削减内源氮释放的缓释氧材料.发现以m(CaO2)∶m(白土)∶m(水泥)=2∶1∶1制备的缓释氧材料具有较好的释氧和pH缓冲能力.通过模拟实验比较缓释氧材料不同投加方式(表层投加和泥内投加)对释氧和沉积物中污染物释放的影响.结果表明:1)表层投加缓释氧材料使得上覆水...

EFFECTS OF DIFFERENT DOSING METHODS OF SLOW-RELEASE OXYGEN COMPOSITE MATERIALS ON THE MIGRATION OF POLLUTANTS AT THE SEDIMENT-WATER INTERFACE

In order to improve the lake sediment-water interface habitat, a slow-release oxygen material that can supply oxygen in situ and reduce the release of endogenous nitrogen was developed. The slow-release oxygen material prepared with CaO₂:white clay:cement=2:1:1 (mass ratio) had good oxygen release and pH buffering capability. The simulation experiment compared the effects of different dosing methods of slow-release oxygen materials (surface dosing and in-mud dosing) on the release of oxygen and the release of pollutants in the sediments. The results showed that:1) the DO concentration and pH value of the overlying water were significantly increased by surface dosing, and in-mud dosing could maintain the pH value within 7.5, while the DO concentration increased slowly, prolonging the oxygen release period; 2) slow-release oxygen materials had a significant inhibitory effect on release of NH₄+-N in the sediment, and surface dosing was significantly effective than in-mud dosing. Taking the blank group as the reference, after 31 days of static culture, the inhibition rate of NH₄+-N by adding slow-release oxygen material into the mud was 53.4%, and that of the surface dosing was 81.1%. Adding oxygen-releasing materials increased the level of DO in the overlying water and promoted the growth of nitrifying bacteria, thereby inhibiting the release of NH₄+-N; 3) slow-release oxygen materials were beneficial to microorganisms growth which promoted the humification of microorganisms, thereby slightly promoted the release of terrestrial-like humic acids in the sediments, while slightly inhibited the release of tyrosine-like proteins; 4) slow-release oxygen materials could promote the conversion of Fe/Al-P to Ca-P in the sediment which slightly inhibited the release of DIP, but the release of DOC and arsenic and chromium in the sediment increased slightly, due to the increase of pH.