Institute of Water Chemistry, Technische Universität Dresden, D-01062 Dresden, Germany.
VKTA Nuclear Engineering and Analytics Inc., P.O. Box 510119, D-01314 Dresden, Germany.
Water Res. 2015 Mar 15;71:219-26. doi: 10.1016/j.watres.2015.01.001. Epub 2015 Jan 10.
At a progressive rate, small wastewater treatment plants in rural areas need to be equipped with an additional phosphorus removal stage in order to achieve a good chemical status in the receiving natural water bodies. A conventional regeneration method for ferric (hydr)oxides such as phosphate specific adsorbents, which can be applied to remove and recover phosphorus in fixed bed filters, was investigated and improved. It was shown that a loss of up to 85% of the initial capacity can be observed when regeneration with 1 M NaOH is implemented. The losses are caused by surface blocking with different calcium-containing compounds as revealed by an EDX analysis. These blocking compounds could be removed completely with an additional acidic regeneration step at pH = 2.5. During the alkaline desorption that followed, complete phosphorus removal and a full recovery of the adsorption capacity were achieved for goethite-rich Bayoxide(®) E 33 HC (E33HC) and akaganéite-rich GEH(®) 104 (GEH). The regeneration procedure was repeated up to eight times without any signs of further decline in the phosphate adsorption capacity or any changes in the specific surface area or pore size distribution of the adsorbent. In contrast to GEH and E33HC, ferric hydroxide- and calcite-rich FerroSorp(®) Plus (FSP) was partly dissolved during acid treatment.
为了达到受纳天然水体的良好化学状态，农村地区的小型废水处理厂需要逐步配备额外的除磷设施。本研究调查并改进了一种常规的铁（氢）氧化物再生方法，如针对磷酸盐的专用吸附剂，可应用于固定床过滤器中去除和回收磷。结果表明，当使用 1 M NaOH 进行再生时，初始容量最高损失可达 85%。通过 EDX 分析表明，这些损失是由不同的含钙化合物导致的表面堵塞造成的。通过在 pH = 2.5 时进行额外的酸性再生步骤，可以完全去除这些堵塞化合物。随后进行的碱性解吸，使富含针铁矿的 Bayoxide(®) E 33 HC (E33HC) 和富含纤铁矿的 GEH(®) 104 (GEH) 完全去除磷，并完全恢复吸附能力。该再生程序可重复进行多达 8 次，而不会对磷酸盐吸附容量或吸附剂的比表面积或孔径分布产生任何进一步下降的迹象。与 GEH 和 E33HC 不同的是，富铁氢氧化物和方解石的 FerroSorp(®) Plus (FSP) 在酸处理过程中部分溶解。
