磁铁锆改性牡蛎壳对水体磷的控释行为研究

通过磁化和添加溶解性锆盐，制成一种磁铁锆改性牡蛎壳粉材料，对其性质及除磷效果进行研究.结果表明，经磁铁锆改性，牡蛎壳具备磁性且比表面积和孔隙度均得到了显著提升，磷吸附量由4.5 mg·g^-1提高到了46.5 mg·g^-1，同时通过外加磁场可成功实现改性牡蛎壳粉的回收，而吸附动力学研究则证明整个磷吸附过程包括快速吸附和平衡吸附两个阶段.另外，改性牡蛎壳粉末对于水体中磷的吸附主要以溶解性磷酸盐（SRP）为主，相较于底泥间隙水，改性牡蛎壳粉对底泥上覆水的释磷行为具有更好的抑制效果，同时该材料还会促进底泥磷形态中易释放的铁结合态磷（Fe-P）向难释放的闭蓄态磷（Oc-P）转化，并降低易释放交换态磷（Ex-P）的含量.上述结果说明磁铁锆改性牡蛎壳适合作为一种高效除磷吸附剂用于控制富营养化水体中磷过量现象.

The controlled release of phosphorus in water by magnet zirconium modified oyster shell

A magnet zirconium modified oyster shell powder material was prepared by magnetization and addition of soluble zirconium salt, and then its properties and phosphorus removal capability were studied. The results showed that the modified material was magnetic, and the specific surface area and porosity increased remarkably compared with that before modification. The phosphorus adsorption amount of oyster shell also increased from 4.5 mg·g^-1 to 46.5 mg·g^-1, and the modified oyster shell can be successfully recycled by applying a magnetic field. The adsorption kinetics study showed that the whole phosphorus adsorption process included two stages of rapid adsorption and equilibrium adsorption. In addition, the modified oyster shell mainly adsorbed the soluble phosphate (SRP) in water. Compared with the interstitial water, the modified oyster shell exhibited a more obvious inhibition effect on the phosphorus release of the overlying water. The modified material might promote the transformation of the easily released iron-bound P (Fe-P) to the hard released sequestered P (Oc-P), and reduce the concentration of easily released exchanged P (Ex-P).The above mentioned results indicate that the magnet zirconium-modified oyster shell can be used as an efficient phosphorus removal adsorbent for the eutrophication treatment.