沸石/水合氧化锆吸附水中的磷

以粉煤灰为原料，采用传统水热方法制备的沸石除磷性能有限，且存在废碱液排放的问题。对此，本文首次提出了在传统水热方法基础上用氯氧化锆中和合成沸石过程中产生的废碱液，得到沸石/水合氧化锆复合吸附剂（简称锆沸石）的改进方法。锆沸石的比表面积为1.931×105 m2·kg-1，是沸石的近7倍。锆沸石的XRD衍射峰数量和位置与沸石相同，证明锆沸石中的水合氧化锆为无定形。锆沸石对磷的Langmuir最大吸附量为22.62 mg·g-1。吸附动力学实验结果表明，锆沸石对磷的吸附速率呈先快后慢的趋势。锆沸石对磷的吸附随pH上升而减少。水中常见的阴离子Cl-、NO3-不会对其除磷效果产生明显影响，而HCO32-会通过提高溶液pH值明显降低吸附量。因此，以粉煤灰为原料，采用改进的合成方法制备锆沸石可获得除磷效果大幅提高的新型吸附剂。

Phosphate adsorption from water by zeolite/hydrous zirconium oxide composite synthesized from coal fly ash

Zeolites synthesized from coal fly ash via the traditional hydrothermal process have limited phosphate-binding ability, and the waste alkaline solution produced during the traditional synthesis procedure poses environmental problems. To overcome these limitations, this paper proposes a new method to produce a zeolite/hydrous zirconium oxide composite (abbreviated as ZHZO hereafter) by adding a step in which the waste alkaline solution is neutralized with ZrOCl2 solution following the traditional hydrothermal process. The specific surface area of ZHZO reached 1.967×105 m2·kg-1, which was nearly 7-fold greater than that of zeolite. The number and location of peaks in the XRD patterns were the same for ZHZO and zeolite, indicating that the hydrous zirconium oxide in the composite material was amorphous. The Langmuir maximum phosphate adsorption capacity of ZHZO was 22.62 mg·g-1. The results of an adsorption kinetics study showed that the phosphate adsorption process of ZHZO was relatively fast at first and then slowed down. The adsorption of phosphate by ZHZO decreased with increasing pH, and chloride and nitrate anions, which commonly coexist in water, had no obvious effect on its adsorption, although HCO32- reduced the adsorption significantly by increasing the pH. Therefore, the ZHZO obtained from coal fly ash using our new procedure is a novel adsorbent with a greatly enhanced ability to remove phosphate from water.