Phosphate recovery as vivianite using a flow-electrode capacitive desalination (FCDI) and fluidized bed crystallization (FBC) coupled system

Changyong Zhang; Xiang Cheng; Min Wang; Jinxing Ma; Richard Collins; Andrew Kinsela; Ying Zhang; T David Waite

doi:10.1016/j.watres.2021.116939

Phosphate recovery as vivianite using a flow-electrode capacitive desalination (FCDI) and fluidized bed crystallization (FBC) coupled system

Water Res. 2021 Apr 15:194:116939. doi: 10.1016/j.watres.2021.116939. Epub 2021 Feb 18.

Authors

Changyong Zhang¹, Xiang Cheng², Min Wang³, Jinxing Ma⁴, Richard Collins⁵, Andrew Kinsela⁶, Ying Zhang⁷, T David Waite⁸

Affiliations

¹ UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: changyong.zhang@unsw.edu.au.
² Beijing Key Laboratory for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China. Electronic address: xcheng@bjfu.edu.cn.
³ UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: min.wang1@student.unsw.edu.au.
⁴ UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: jinxing.ma@unsw.edu.au.
⁵ UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: richard.collins@unsw.edu.au.
⁶ UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: a.kinsela@unsw.edu.au.
⁷ Beijing Origin Water Membrane Technology Company Limited, Huairou, Beijing, 101400, P. R. China. Electronic address: zhangying9663@126.com.
⁸ UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia; UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu Province 214206, P. R. China. Electronic address: d.waite@unsw.edu.au.

PMID: 33640752
DOI: 10.1016/j.watres.2021.116939

Abstract

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 (LiFePO₄), 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.

Keywords: Flow-electrode capacitive deionization; Fluidized bed crystallization; Phosphate removal and recovery; Vivianite.

MeSH terms

Crystallization
Electrodes
Ferrous Compounds
Phosphates
Water Purification*

Substances

Ferrous Compounds
Phosphates
ferrous phosphate