Basket anode filled with CaCO3 particles: A membrane-free electrochemical system for boosting phosphate recovery and product purity

Zhan，Zhengshuo1; Wang，Runhua1; Saakes，Michel2; van der Weijden，Renata D.2,3; Buisman，Cees J.N.2,3; Lei，Yang1

2023-03-01

10.1016/j.watres.2023.119604

WATER RESEARCH   Impact Factor & Quartile

0043-1354

1879-2448

Phosphorus (P) is often regarded as the primary stimulant for eutrophication, while its importance as a crucial life element is also well acknowledged. Given its future scarcity, P recycling from waste streams is suggested and practiced. Electrochemically mediated precipitation (EMP) is a robust and chemical-free process for P removal and recovery, yet it requires further developments. The first generation of the CaCO-packed electrochemical precipitation column successfully solved the problem of H-OH recombination, achieving enhanced P removal efficiency with less energy consumption but suffering from low Ca-phosphate purity in recovered products. Herein, a new concept of a basket-anode electrochemical system is proposed and validated to prevent direct H-OH recombination and enhance product purity. The CaCO pellets packed basket anode alleviates the OH depletion by CaCO-H interaction and provides extra Ca for enhanced P removal. The novel structure of the basket anode, by its derived acidic anode region and alkaline cathode region, completely avoids the precipitation of Ca-phosphate on the packed CaCO and greatly facilitates the collection of high-quality Ca-phosphate product. Our results suggest that almost 100% of the removed P was in high-purity, highly crystalline Ca-phosphate on the cathode. The recovered products contained significantly more P (13.5 wt%) than in the previous study (0.1 wt%) at similar energy consumptions (29.8 kWh/kg P). The applied current density, pellets size, and influent P concentration were critical for P removal performance, product purity, and power consumption. We further demonstrated the long-term stability of this novel system and its technical and economic feasibility in treating real stored urine. Our study provides new cell architectural designs to enhance the performance of EMP systems and may inspire innovations and developments in other electrochemical water treatment processes.

Basket anode High-purity products Local pH Long-term application Phosphate recovery

English

NI Journal Papers

First ; Corresponding

ENVIRONMENT/ECOLOGY

2-s2.0-85146471081

Scopus

1.School of Environmental Science and Engineering,Southern University of Science and Technology (SUSTech),Shenzhen,518055,China
2.Wetsus,Centre of Excellence for Sustainable Water Technology,Leeuwarden,P.O. Box 1113,8900CC,Netherlands
3.Department of Environmental Technology,Wageningen University and Research,Wageningen,P.O. Box 17,6700AA,Netherlands

Zhan，Zhengshuo,Wang，Runhua,Saakes，Michel,et al. Basket anode filled with CaCO3 particles: A membrane-free electrochemical system for boosting phosphate recovery and product purity[J]. WATER RESEARCH,2023,231.

Zhan，Zhengshuo,Wang，Runhua,Saakes，Michel,van der Weijden，Renata D.,Buisman，Cees J.N.,&Lei，Yang.(2023).Basket anode filled with CaCO3 particles: A membrane-free electrochemical system for boosting phosphate recovery and product purity.WATER RESEARCH,231.

Zhan，Zhengshuo,et al."Basket anode filled with CaCO3 particles: A membrane-free electrochemical system for boosting phosphate recovery and product purity".WATER RESEARCH 231(2023).