Membrane-separated electrochemical latrine wastewater treatment

Yang, Yang; Lin, Lin; Tse, Leda K.; Dong, Heng; Yu, Shaokun Carol; Hoffmann, Michael R.

doi:10.1039/c8ew00698a

Cited by 29 publications

(25 citation statements)

References 43 publications

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“…As for the transport of phosphoric acid anions through AEM, this subject is of considerable interest not only for theory but also for practice. Isolation, purification, and concentration of these anions from municipal wastewater [33,34,35], animal waste [2,36], and sludge generated after its biological treatment [37,38] not only reduces the anthropogenic impact on the environment, but also allows for obtaining cheap fertilizers with simultaneous production of electricity [38]. It is important that the current efficiency in the recovery of phosphorus from solutions containing H 2 PO 4 − ions is significantly lower as compared to similar processes in the case of nitrates, chlorides, and other ions that do not undergo protonation–deprotonation reactions [2,34,39,40,41].…”

Section: Introductionmentioning

confidence: 99%

Partial Fluxes of Phosphoric Acid Anions through Anion-Exchange Membranes in the Course of NaH2PO4 Solution Electrodialysis

Rybalkina

Tsygurina

Melnikova

et al. 2019

IJMS

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Electrodialysis (ED) with ion-exchange membranes is a promising method for the extraction of phosphates from municipal and other wastewater in order to obtain cheap mineral fertilizers. Phosphorus is transported through an anion-exchange membrane (AEM) by anions of phosphoric acid. However, which phosphoric acid anions carry the phosphorus in the membrane and the boundary solution, that is, the mechanism of phosphorus transport, is not yet clear. Some authors report an unexpectedly low current efficiency of this process and high energy consumption. In this paper, we report the partial currents of H2PO4−, HPO42−, and PO43− through Neosepta AMX and Fujifilm AEM Type X membranes, as well as the partial currents of H2PO4− and H+ ions through a depleted diffusion layer of a 0.02 M NaH2PO4 feed solution measured as functions of the applied potential difference across the membrane under study. It was shown that the fraction of the current transported by anions through AEMs depend on the total current density/potential difference. This was due to the fact that the pH of the internal solution in the membrane increases with the growing current due to the increasing concentration polarization (a lower electrolyte concentration at the membrane surface leads to higher pH shift in the membrane). The HPO42− ions contributed to the charge transfer even when a low current passed through the membrane; with an increasing current, the contribution of the HPO42− ions grew, and when the current was about 2.5 ilimLev (ilimLev was the theoretical limiting current density), the PO43− ions started to carry the charge through the membrane. However, in the feed solution, the pH was 4.6 and only H2PO4− ions were present. When H2PO4− ions entered the membrane, a part of them transformed into doubly and triply charged anions; the H+ ions were released in this transformation and returned to the depleted diffusion layer. Thus, the phosphorus total flux, jP (equal to the sum of the fluxes of all phosphorus-bearing species) was limited by the H2PO4− transport from the bulk of feed solution to the membrane surface. The value of jP was close to ilimLev/F (F is the Faraday constant). A slight excess of jP over ilimLev/F was observed, which is due to the electroconvection and exaltation effects. The visualization showed that electroconvection in the studied systems was essentially weaker than in systems with strong electrolytes, such as NaCl.

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Section: Introductionmentioning

confidence: 99%

Partial Fluxes of Phosphoric Acid Anions through Anion-Exchange Membranes in the Course of NaH2PO4 Solution Electrodialysis

Rybalkina

Tsygurina

Melnikova

et al. 2019

IJMS

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“…NH + 4 and PO 3− 4 recoveries up to 90% have been demonstrated. Further, the use of AEM and CEM divided cells to treat latrine wastewater and recovery of NH + 4 and PO 3− 4 has been reported very recently (Yang et al, 2019). The study also reports that 39% less chlorate (ClO −…”

Section: Introductionmentioning

confidence: 87%

Membrane Selection for Electrochemical Treatment of Septage

Talekar

Mutnuri

2020

Front. Energy Res.

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“…Over the last years, membrane-based processes have shown many benefits and are often preferred over membrane-free processes [234]. The use of ionexchange membranes exclude undesired side reactions in the electrolyte, improve the process efficiency and offer enhanced selectivity and resource recovery by forming a physical barrier between anode and cathode [11,235]. The economic gain of these membrane-based processes is mainly dominated by the operating costs such as energy consumption, which is, in its turn, significantly determined by the membrane performance [16].…”

Section: Ion-exchange Nanofibers In Electrochemical Water Treatment A...mentioning

confidence: 99%

A review on ion-exchange nanofiber membranes: properties, structure and application in electrochemical (waste)water treatment

Swanckaert

Geltmeyer

Rabaey

et al. 2022

Separation and Purification Technology

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Membrane-separated electrochemical latrine wastewater treatment

Abstract: Membrane electrolysis is shown to be durable over one month of continuous operation.

Cited by 29 publications

References 43 publications

Partial Fluxes of Phosphoric Acid Anions through Anion-Exchange Membranes in the Course of NaH2PO4 Solution Electrodialysis

Partial Fluxes of Phosphoric Acid Anions through Anion-Exchange Membranes in the Course of NaH2PO4 Solution Electrodialysis

Membrane Selection for Electrochemical Treatment of Septage

A review on ion-exchange nanofiber membranes: properties, structure and application in electrochemical (waste)water treatment

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