College of Environmental Science and Engineering, Ocean University of China, No. 238 Songling Road, Qingdao 266100, Shandong Province, People's Republic of China.
lnstitute for Water, University of Stuttgart, Pfaffenwaldring 61, Stuttgart 70569, Germany.
Environ Technol. 2014 Jan-Feb;35(1-4):60-9. doi: 10.1080/09593330.2013.808268.
Sediment capping is an in situ treatment technology that can effectively restrain nutrient and pollutant release from the sediment in lakes and reservoirs. Research on sediment capping has focused on the search for effective, non-polluting and affordable capping materials. The efficiency and mechanism of sediment capping with modified palygorskite in preventing sediment ammonia nitrogen (NH4+-N) release to surface water were investigated through a series of batch and sediment capping experiments. Purified palygorskite and different types of modified palygorskite (i.e. heated, acid-modified and NaCI-modified palygorskite) were used in this investigation. Factors affecting control efficiency, including the temperature, thickness and grain size of the capping layer, were also analysed. The batch tests showed that the adsorption of NH4+-N on modified palygorskite achieved an equilibration in the initial 45 min, and the adsorption isotherm followed the Freundlich equation. Sediment capping experiments showed that compared with non-capped condition, covering the sediment with modified palygorskite and sand both inhibited NH4+-N release to the overlying water. Given its excellent chemical stability and strong adsorption, heated palygorskite, which has a NH4+-N release inhibition ratio of 41.3%, is a more effective sediment capping material compared with sand. The controlling effectiveness of the modified palygorskite increases with thicker capping layer, lower temperature and smaller grain size of the capping material.
底泥覆盖是一种原位处理技术，可有效抑制湖泊和水库底泥中营养物质和污染物的释放。底泥覆盖的研究主要集中在寻找有效、无污染且经济实惠的覆盖材料上。通过一系列批处理和底泥覆盖实验，研究了改性坡缕石对防止底泥氨氮（NH4+-N）向地表水释放的覆盖效率和机制。本研究使用了纯化坡缕石和不同类型的改性坡缕石（即加热、酸改性和 NaCl 改性坡缕石）。还分析了影响控制效率的因素，包括覆盖层的温度、厚度和粒径。批处理实验表明，NH4+-N 在改性坡缕石上的吸附在初始 45 分钟内达到平衡，吸附等温线遵循 Freundlich 方程。底泥覆盖实验表明，与未覆盖条件相比，改性坡缕石和砂覆盖底泥均能抑制 NH4+-N 向覆盖水的释放。加热坡缕石具有出色的化学稳定性和较强的吸附能力，其 NH4+-N 释放抑制率为 41.3%，比砂更能有效抑制底泥中 NH4+-N 的释放，是一种更有效的底泥覆盖材料。改性坡缕石的控制效果随覆盖层厚度增加、温度降低和覆盖材料粒径减小而增强。
