Mitigating magnesium electrode fouling through polarity reversal electrocoagulation for struvite production from source-separated urine

IF 6.7 2区工程技术 Q1 ENGINEERING, CHEMICAL

Journal of water process engineering Pub Date : 2025-06-12 DOI:10.1016/j.jwpe.2025.108117

Alisha Zaffar, Jayaraman Sivaraman, Paramasivan Balasubramanian

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Abstract

Electrochemical struvite precipitation is proposed to be an effective technology for phosphate recovery to tackle the problem of depleting phosphate rocks and eutrophication. However, the corrosion of magnesium ions from the anode is hindered due to passivation, limiting the technological scale-up. The study aims to investigate and reduce passivation of magnesium electrode for struvite precipitation from fresh, source separated urine. The corrosion and passivation pattern of magnesium was investigated using electrochemical techniques Furthermore, polarity reversal electrocoagulation (PR-EC) at different polarity reversal time (PRT) between 0 and 10 min concluded an maximum phosphorus recovery (>98 %) and struvite precipitation (1.90 g L⁻¹) at PRT of 5 min. Enhanced corrosion due to reduction of electrode fouling was further confirmed with comparable corrosion rate (19.36 mm year⁻¹) of the used electrode at PRT 5 min to the fresh electrode (24.35 mm year⁻¹) extrapolated from the Tafel plot. Moreover, the production of struvite was confirmed by FTIR, XRD, SEM-EDX. The decrease of phosphate recovery in sequence batch experimental runs was non-significant for PR-EC, confirming its efficiency over direct current electrocoagulation. Further, with an increase of surface area by volume ratio, faster phosphate recovery was achieved. Overall, PR-EC is an efficient method for struvite precipitation from source-separated urine.

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通过极性反转电凝从源分离尿液中生产鸟粪石，减轻镁电极污染

鸟粪石电化学沉淀法是一种有效的磷矿回收技术，可有效解决磷矿耗竭和富营养化问题。然而，由于钝化，阳极的镁离子的腐蚀受到阻碍，限制了技术的扩大。研究镁电极对新鲜源分离尿液中鸟粪石沉淀的钝化作用。利用电化学技术研究了镁的腐蚀和钝化模式。极性逆转电凝（PR-EC）在0到10分钟的不同极性逆转时间（PRT）下得出最大磷回收率（> 98%）和鸟粪石沉淀（1.90 g L−1）。通过Tafel图推断，在PRT 5分钟时，使用电极的腐蚀速率（19.36 mm年−1）与新电极的腐蚀速率（24.35 mm年−1）相当，进一步证实了电极污染减少导致的腐蚀增强。并通过FTIR、XRD、SEM-EDX等手段证实了鸟粪石的合成。在序批实验中，PR-EC的磷酸盐回收率下降不显著，证实了其优于直流电凝的效率。此外，随着表面积体积比的增加，磷酸盐的回收速度更快。总的来说，PR-EC是一种从源分离尿液中沉淀鸟粪石的有效方法。

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来源期刊

Journal of water process engineering Biochemistry, Genetics and Molecular Biology-Biotechnology

CiteScore

10.70

自引率

8.60%

发文量

846

审稿时长

24 days

期刊介绍： The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies