UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
Beijing Key Laboratory for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
Water Res. 2021 Apr 15;194:116939. doi: 10.1016/j.watres.2021.116939. Epub 2021 Feb 18.
It is critical to both effectively remove and recover phosphate (P) from wastewater given the wide-ranging environmental (i.e., preventing eutrophication and restoring water quality) and economic (i.e., overcoming P resource scarcity) benefits. More recently, considerable academic effort has been devoted towards harvesting P as vivianite, which can be used as a potential slow-release fertilizer and possible reagent for the manufacture of lithium iron phosphate (LiFePO), the precursor in fabricating Li-ion secondary batteries. In this study, we propose an innovative P recovery process, in which P is first preconcentrated via a flow-electrode capacitive deionization (FCDI) device followed by immobilization as vivianite crystals in a fluidized bed crystallization (FBC) column. The effects of different operational parameters on FCDI P preconcentration performance and energy consumption are investigated. Results show that 63% of P can be removed and concentrated in the flow-electrode chamber with a reasonable energy requirement under optimal operating conditions. The FBC system resulted in immobilization of ~80% of P as triangular or quadrangular pellets, which were verified to be high-purity vivianite crystals by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and extended X-ray absorption fine structure (EXAFS) spectroscopy. This study provides a pathway for efficient recovery of P as a value-added product (i.e., vivianite) from P-rich wastewaters.
鉴于从废水中有效去除和回收磷（P）具有广泛的环境（即防止富营养化和恢复水质）和经济（即克服 P 资源短缺）效益，因此这一点至关重要。最近，人们投入了相当多的学术努力来收获磷作为蓝铁矿，这可以用作潜在的缓释肥料和制造磷酸铁锂（LiFePO）的可能试剂，LiFePO 是制造锂离子二次电池的前体。在这项研究中，我们提出了一种创新的 P 回收工艺，首先通过流动电极电容去离子（FCDI）装置预浓缩 P，然后在流化床结晶（FBC）柱中固定为蓝铁矿晶体。研究了不同操作参数对 FCDI P 预浓缩性能和能耗的影响。结果表明，在最佳操作条件下，通过流动电极室可去除和浓缩 63%的 P，且所需能量合理。FBC 系统将约 80%的 P 固定为三角形或四边形颗粒，通过扫描电子显微镜与能量色散 X 射线光谱（SEM-EDX）和扩展 X 射线吸收精细结构（EXAFS）光谱证实这些颗粒为高纯度蓝铁矿晶体。本研究为从富磷废水中以附加值产品（即蓝铁矿）高效回收 P 提供了一种途径。
