磁性Ca/Al水滑石对挥发性脂肪酸的吸附性能

污水脱氮除磷处理过程中使用的液态碳源存在投加量难以控制以及容易影响出水水质、增大处理费用等缺点。针对此现状,采用超声辅助法以超顺磁性铁氧体材料对制备的Ca/Al水滑石进行复合改性合成磁性Ca/Al水滑石，研究以其作为载体对挥发性脂肪酸(VFA)的吸附提取性能，考察了磁性Ca/Al水滑石吸附剂剂量、吸附时间和转速对VFA吸附效果的影响，并通过均匀实验设计，采用响应面法优化吸附提取参数。结果表明：当吸附剂剂量为16 g·L-1，吸附时间为50 min，转速为70 r·min-1时，该材料对VFA的理论最大吸附效率为95.7%。由于材料自身具有磁性特性，经提取后的混合液在外加磁场的作用下，能够实现磁性Ca/Al水滑石的快速回收。同时，将回收再生后的磁性Ca/Al水滑石对VFA的吸附提取性能进行了研究，发现在吸附解吸3次循环后仍然有很好的吸附效果。表明利用该磁性Ca/Al水滑石提取VFA是可行的，为后续将其作为固态可控外加碳源的研究奠定了基础。

Performance of magnetic Ca/Al layered double hydroxides on adsorption of volatile fatty acid

Liquid carbon source used in the denitrification and phosphorus removal process from sewage could cause difficult dosage control, impact the effluent water quality and raise the processing costs. For this situation, an ultrasonic assisted method was used in this study to synthesize a magnetic Ca/Al hydrotalcite through modifying the prepared Ca/Al hydrotalcite with super-paramagnetic ferrite, and the adsorption performance of magnetic Ca/Al hydrotalcite as carrier on volatile fatty acid (VFA) was investigated. The effects of adsorbent dosage, adsorption duration and speed on the extraction of VFA were tested, and the extraction parameters were also optimized using uniform design and response surface methodology. The result shows that the theoretical maximum VFA extraction rate by magnetic Ca/Al hydrotalcite could reach 95.7% after 50min adsorption at the adsorbent dosage of 16 g·L-1 and adsorption speed of 70 r·min-1. Owing to the magnetic property of this Ca/Al hydrotalcite, it can be quickly recycled when the mixture was treated with an external magnetic field. Meanwhile, the regenerated magnetic Ca/Al hydrotalcite was used to conduct an adsorption experiment of VFA, and good VFA extraction effect still occurred after 3 cycles of adsorption and desorption. This phenomenon indicates that using the magnetic Ca/Al hydrotalcite to extract VFA is feasible, which will lay the foundation for further study on the usage of this hydrotalcite as a solid controllable external carbon source.