Hydrogen production from urea in human urine using segregated systems

Asiain-Mira, Ruben; Smith, Collin; Zamora, Patricia; Monsalvo, Victor M.; Torrente‐Murciano, Laura

doi:10.1016/j.watres.2022.118931

Cited by 9 publications

(5 citation statements)

References 51 publications

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“…Figure b shows the FTIR spectra before and after phosphate adsorption. The Mg–Fe LDH material presents bands at 3300 cm –1 which represents O–H stretching vibrations from structural hydroxyl groups, at 1644 cm –1 which indicates O–H bending vibration from interstitial water molecules, and at 1405 cm –1 which shows the presence of CO 3 2– in the interlayer region of the material. − A new peak appears after phosphate adsorption onto Mg–Fe LDH at 1040 cm –1 , assigned to the symmetrical stretching vibration of PO 4 . − , The intensity of this phosphate band increases with an increase in the initial phosphate concentration. The peaks shown between 2350 and 2000 cm –1 are a combination of atmospheric CO 2 and moisture from air.…”

Section: Resultsmentioning

confidence: 99%

“…A completely new alternative approach for its recovery is the deployment of decentralized wastewater systems (i.e., no-mix toilets) to collect and treat urine as a separate waste stream, offering the opportunity to recover phosphate more efficiently at the production point, avoiding its dilution. 16 The applicability of urine diversion toilets as an alternative to centralized systems started diffusing from 2010 onward mostly in developing countries, where access to proper sanitation is needed. A large-scale rural and peri-urban sanitation program in Durban, South Africa, was implemented by Bill and Melinda Gates Foundation.…”

Section: ■ Introductionmentioning

confidence: 99%

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Phosphate Recovery from Urine-Equivalent Solutions for Fertilizer Production for Plant Growth

Avena Maia,

Kranse,

Eves-van den Akker

et al. 2023

ACS Sustainable Chem. Eng.

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This study presents a proof of concept for the recovery of phosphate from aqueous solutions with high phosphorus (PO4–P) initial contents to simulate the concentration of streams from decentralized wastewater systems. Solutions with ∼500 ppm phosphorus enable phosphate adsorption and recovery, in contrast to the highly diluted inlet streams (<10 ppm) from centralized wastewater treatment plants. In this work, Mg–Fe layered double hydroxide is used as a phosphate adsorbent, demonstrating its separation from aqueous streams, recovery, and use as a fertilizer following the principles of circular economy. We demonstrate that the mechanism of phosphate adsorption in this material is by a combination of surface complexation and electrostatic attraction. After the loss of crystallinity in the presence of water in the first cycle and its associated decrease in adsorption capacity, the Mg–Fe layered double hydroxide (LDH) is stable after consecutive adsorption/desorption cycles, where desorption solutions were reused to substantially increase the final phosphate concentration demonstrating the recyclability of the material in a semicontinuous process. Phosphate recovered in this way was used to complement phosphate-deficient plant growth medium, demonstrating its efficacy as a fertilizer and thereby promoting a circular and sustainable economy.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Phosphate Recovery from Urine-Equivalent Solutions for Fertilizer Production for Plant Growth

Avena Maia,

Kranse,

Eves-van den Akker

et al. 2023

ACS Sustainable Chem. Eng.

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“…The zero-point charge of IP@C400 was investigated in aqueous solutions at pH 4.2, indicating that it tended to adjust the pH of the solutions to approximately 4.2 44 . However, urea has also been reported to act as a slight buffering agent in water within the aforementioned pH range, stabilizing pH levels at approximately 7 through proton donation/acceptance 12 . For initial pH values below 4 or above 10, the solution pH did not change signi cantly because it was far from the point charge of IP@C400.…”

Section: Samplesmentioning

confidence: 99%

“…Among these technologies, biological processes can be used to remove urea. However, general biological processes are incapable of recovering urea 12,13 . In addition, when the initial urea concentration is high, this process is insu cient to reduce it to ppm or ppb levels 5 .…”

Section: Introductionmentioning

confidence: 99%

Super-sorption capacity and multi-cycle recovery of urea from aqueous solutions by vesicle-like iron phosphate-based carbon nano-adsorbent

Jang,

Nguyen,

Jeon

et al. 2024

Preprint

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Despite the versatile potential applications of urea, its utilization is hindered by its unfavorable characteristics for conventional treatment methods.This necessitates the development of urea removal and recovery methods. Therefore, this study developed vesicle-like iron phosphate-based carbon (IP@C400) as a breakthrough urea removal and recovery adsorbent. IP@C400 exhibited an exceptional adsorption capacity (2242 mg/g) at a fast rate (within 2 h) across a wide range of pH environments, even in the presence of high concentrations of co-existing components, compared with the top 60 recent urea adsorbents. The adsorption process followed dual pseudo-kinetic and Langmuir isotherm models, indicating the involvement of both chemical and physical interactions between urea and the homogeneous monolayered adsorbent surface. The mechanisms included H-bonding and electrostatic attraction, as demonstrated by FT-IR and pH investigations. Remarkably, IP@C400 can be reused 10 times without significant loss of efficiency (90%) or recovery (95%)–a significant improvement over disposable options. The tests also showed safe leaching of iron and phosphorus, with levels below drinking water standards. IP@C400 worked effectively on real-world water samples, resulting in the complete removal and excellent recovery of urea. Thus, IP@C400 affords a sustainable, high-performance solution to the critical ultrapure water issue that industries must urgently address.

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“…Table 1 lists a small selection of recipes that have been used in different studies to prepare synthetic urine or are referred to in studies as human urine. While this list is certainly not exhaustive, it clearly shows that there is considerable variation in the choice of inorganic and organic ingredients used for making urine, with some recipes using just one metabolite (Asiain-Mira et al, 2022) and some using up to 11 metabolites (Wilsenach et al, 2007). Urine also has a natural bacterial biome (Lewis et al, 2013) and virome (Li et al, 2023) which is not accounted for by these recipes.…”

Section: Real Human Urine Metabolome Vs Synthetic Human Urine Metabolomementioning

confidence: 99%

An urgent call for using real human urine in decentralized sanitation research and advancing protocols for preparing synthetic urine

Simha,

Courtney,

Randall

2024

Front. Environ. Sci.

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Recycling resources excreted in human urine can help achieve a sustainable future and circular economy in the sanitation space. However, many studies researching different technologies for safely recycling urine do not use real human urine for experimentation, relying instead on recipes for making synthetic or artificial solutions that attempt to mimic the composition of real human urine. This methodological choice is the focus of this article, which points out that the real urine matrix is extremely complex, with a metabolome (>2,500 metabolites) that differs greatly from that of synthetic urine (<15 metabolites). Therefore, experimental results obtained using synthetic urine can also differ from those obtained using real urine. To exemplify this, we review published literature in terms of four aspects: i) solubility of chemicals and buffering capacity of urine, ii) dissolved organics and membrane fouling, iii) thermodynamic modelling of chemical speciation in urine, and iv) removal of pollutants from urine. We recognise that there is a place for synthetic urine in sanitation research and provide examples of studies where its use is appropriate. Lastly, based on literature from the medical sciences, we provide preliminary guidelines on protocols for preparing synthetic urine that could improve experimentation involving human urine and accelerate the water sector’s transition to circularity.

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Hydrogen production from urea in human urine using segregated systems

Cited by 9 publications

References 51 publications

Phosphate Recovery from Urine-Equivalent Solutions for Fertilizer Production for Plant Growth

Phosphate Recovery from Urine-Equivalent Solutions for Fertilizer Production for Plant Growth

Super-sorption capacity and multi-cycle recovery of urea from aqueous solutions by vesicle-like iron phosphate-based carbon nano-adsorbent

An urgent call for using real human urine in decentralized sanitation research and advancing protocols for preparing synthetic urine

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