Department of Civil & Environmental Engineering, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747, USA.
Water Res. 2011 May;45(11):3318-30. doi: 10.1016/j.watres.2011.03.044. Epub 2011 Mar 31.
Influx of Phosphorus (P) into freshwater ecosystems is the primary cause of eutrophication which has many undesirable effects. Therefore, P discharge limits for effluents from WWTPs is becoming increasingly common, and may be as low as 10 μg/L as P. While precipitation, filtration, membrane processes, Enhanced Biological Phosphorus Removal (EBPR) and Physico-chemical (adsorption based) methods have been successfully used to effect P removal, only adsorption has the potential to recover the P as a usable fertilizer. This benefit will gain importance with time since P is a non-renewable resource and is mined from P-rich rocks. This article provides details of a process where a polymeric anion exchanger is impregnated with iron oxide nanoparticles to effectuate selective P removal from wastewater and its recovery as a solid-phase fertilizer. Three such hybrid materials were studied: HAIX, DOW-HFO, & DOW-HFO-Cu. Each of these materials combines the durability, robustness, and ease-of-use of a polymeric ion-exchanger resin with the high sorption affinity of Hydrated Ferric Oxide (HFO) toward phosphate. Laboratory experiments demonstrate that each of the three materials studies can selectively remove phosphate from the background of competing anions and phosphorus can be recovered as a solid-phase fertilizer upon efficient regeneration of the exchanger and addition of a calcium or magnesium salt in equimolar (Ca/P or Mg/P) ratio. Also, there is no leaching of Fe or Cu from any of these hybrid exchangers.
磷（P）流入淡水生态系统是富营养化的主要原因，而富营养化会带来许多不良影响。因此，污水处理厂出水的磷排放限值变得越来越常见，甚至可能低至 10μg/L 作为 P。虽然沉淀、过滤、膜过程、增强生物除磷（EBPR）和物理化学（基于吸附）方法已成功用于除磷，但只有吸附具有将磷回收为可用肥料的潜力。随着时间的推移，这种好处将变得更加重要，因为磷是一种不可再生资源，并且是从富含磷的岩石中开采的。本文详细介绍了一种将聚合物阴离子交换剂浸渍氧化铁纳米粒子以从废水中选择性去除磷并将其回收为固相肥料的过程。研究了三种这样的混合材料：HAIX、DOW-HFO 和 DOW-HFO-Cu。这些材料中的每一种都将聚合物离子交换树脂的耐用性、坚固性和易用性与水合氧化铁（HFO）对磷酸盐的高吸附亲和力结合在一起。实验室实验表明，所研究的三种材料中的每一种都可以从竞争阴离子的背景中选择性地去除磷酸盐，并且可以通过有效再生交换剂并添加等摩尔（Ca/P 或 Mg/P）比例的钙或镁盐来将磷回收为固相肥料。此外，这些混合交换剂中没有铁或铜的浸出。
