The proposal for the completely closed system in the Columbus Space Station

Madsen, R.F.; Thomassen, Jørgen; Vial, D.; Binot, Roger A.

doi:10.1016/0011-9164(91)85089-d

Cited by 7 publications

(5 citation statements)

References 11 publications

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“…The reported concentration of urea in human urine varies widely from 11–25 g/L (0.18–0.42 M), − while 19.82 g/L (0.33 M) is the most commonly used concentration in recent urea electro-oxidation studies. ,,,,, To align our outcomes with previous studies, we chose to use a urea concentration of 0.33 M. Synthetic urine was prepared as described previously but with 19.82 g/L urea instead of 25.0 g/L. Chemicals were used as received and included urea (Amresco, 0568), disodium phosphate (Fisher Scientific, S374-500), monopotassium phosphate (ACS grade, Amresco, 0781), sodium chloride (Fisher Scientific, S271-3), ammonium chloride (BDH, BDH9208), creatinine (TCI, C0398), sodium sulfite (Spectrum, 51475), gelatin, (Amresco, 9764), and Difco nutrient broth (BD, 234000).…”

Section: Methodsmentioning

confidence: 99%

“…The reported concentration of urea in human urine varies widely from 11−25 g/L (0.18−0.42 M), 59−63 while 19.82 g/L (0.33 M) is the most commonly used concentration in recent urea electro-oxidation studies. 9,12,26,35,42,64 To align our outcomes with previous studies, we chose to use a urea concentration of 0.33 M. Synthetic urine was prepared as described previously 65 but with 19.82 g/L urea instead of 25.0 g/L.…”

Section: Methodsmentioning

confidence: 99%

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Effect of Urine Compounds on the Electrochemical Oxidation of Urea Using a Nickel Cobaltite Catalyst: An Electroanalytical and Spectroscopic Investigation

Schranck

Marks

Yates

et al. 2018

Environ. Sci. Technol.

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Cyclic voltammetry (CV) and in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were used to investigate the effect of major urine compounds on the electro-oxidation activity of urea using a nickel cobaltite (NiCoO ) catalyst. As a substrate, carbon paper exhibited better benchmark potential and current values compared with stainless steel and fluorine-doped tin oxide glass, which was attributed to its greater active surface area per electrode geometric area. CV analysis of synthetic urine showed that phosphate, creatinine, and gelatin (i.e., proteins) had the greatest negative effect on the electro-oxidation activity of urea, with decreases in peak current up to 80% compared to that of a urea-only solution. Further investigation of the binding mechanisms of the deleterious compounds using in situ ATR-FTIR spectroscopy revealed that urea and phosphate weakly bind to NiCoO through hydrogen bonding or long-range forces, whereas creatinine interacts strongly, forming deactivating inner-sphere complexes. Phosphate is presumed to disrupt the interaction between urea and NiCoO by serving as a hydrogen-bond acceptor in place of catalyst sites. The weak binding of urea supports the hypothesis that it is oxidized through an indirect electron transfer. Outcomes of this study contribute to the development of electrolytic systems for treating source-separated urine.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effect of Urine Compounds on the Electrochemical Oxidation of Urea Using a Nickel Cobaltite Catalyst: An Electroanalytical and Spectroscopic Investigation

Schranck

Marks

Yates

et al. 2018

Environ. Sci. Technol.

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“…Urine stabilization is necessary when considering treatment of human urine; without stabilization, urea hydrolysis occurs during collection and storage. The purpose of urine stabilization included inhibiting the organic matter degradation and microbial proliferation, as well as preventing an increase in the pH [14]. The urine stabilization in use aboard the ISS is based upon adding chemicals, including hexavalent chromium as a bacteriostat and sulfuric acid as an acidifier [22].…”

Section: Urine Preparationmentioning

confidence: 99%

“…Among them, reverse osmosis (RO) was first studied for water recovery from urine. However, the RO module was unusable after being used once due to the excessive organic foulants in the urine [14]. Studies of urine treatment by forward osmosis (FO) indicated that a water recovery rate of <15% and draw solutions contaminated by permeable organics were the main obstacles for the applications [12,15].…”

Section: Introductionmentioning

confidence: 99%

High-Efficiency Water Recovery from Urine by Vacuum Membrane Distillation for Space Applications: Water Quality Improvement and Operation Stability

Wang

Liu

et al. 2022

Membranes

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Water recovery by membrane distillation (MD) is an attractive alternative to existing urine treatment systems because it could improve the water recovery rate and reliability in space missions. However, there are few studies of urine MD, particularly on the removal of the remaining contaminants from distillate water and the assessment of its long-term performance. In this study, the influences of various operation parameters on distillate water quality and operation stability were investigated in batch mode. The low pH of feedstock reduced the conductivity and total ammonium nitrogen (TAN) in distillate water because the low pH promoted the ionization of ammonia to ammonium ions. However, the low pH also facilitated the formation of free chlorine hydride, which resulted in the minor deterioration of the conductivity in the distillate due to the increasing volatility of chlorine hydride in the feedstock. Thirty batches of vacuum membrane distillation (VMD) experiments demonstrated that the permeate flux and the distillate water quality slightly decreased due to the small range of membrane wetting but still maintained an over 94.2% and 95.8% removal efficiency of the total organic carbon (TOC) and TAN, and the conductivity was <125 μs cm−1 in the distillate water after 30 test batches. VMD is a feasible option for urine treatment in space missions.

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“…66 In space station environments, urine can be acidified to inhibit urease activity then subjected to distillation and filtration. 67 Again this research was with the objective of volume reduction and hygienation rather than the isolation and extraction of urea. One recent study revealed that as a consequence of attempting to separate pharmaceutical pollutants from urine by the use of a nanomembrane, urea was found to permeate on the membrane in relatively high yields.…”

Section: Urea From Urinementioning

confidence: 99%

Urea as a hydrogen carrier: a perspective on its potential for safe, sustainable and long-term energy supply

Rollinson

Jones

Dupont

et al. 2011

Energy Environ. Sci.

246

169

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Recently, there have been publications reporting the use of urea, as a source of hydrogen/fuel cell power. There have however been no reports that singularly assess the suitability of urea for this purpose. This article provides not only a perspective on the attributes of urea ((NH 2 ) 2 CO) as a hydrogen carrier for fuel cells but also presents the findings of a review on the feasibility of utilising the enormous natural resource of urea that exists. Urea is a cheap and widely available commodity with well developed manufacturing infrastructure and a rapidly increasing volume of production. This offers rapid implementation of urea for application as a hydrogen carrie r either directly or as a source of ammonia. Compared with other industrial chemicals previously considered, urea has the advantages of being non-toxic, stable, and therefore easy to transport and store. This report reveals that the natural resource of urea could be a solution to long-term future sustainable hydrogen supply and that the present status of scientific knowledge necessary to extract this natural resource is in the most part understood. It is considered realistic that these sustainable routes could be exploited if they are given sufficient focus of research attention.

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The proposal for the completely closed system in the Columbus Space Station

Cited by 7 publications

References 11 publications

Effect of Urine Compounds on the Electrochemical Oxidation of Urea Using a Nickel Cobaltite Catalyst: An Electroanalytical and Spectroscopic Investigation

Effect of Urine Compounds on the Electrochemical Oxidation of Urea Using a Nickel Cobaltite Catalyst: An Electroanalytical and Spectroscopic Investigation

High-Efficiency Water Recovery from Urine by Vacuum Membrane Distillation for Space Applications: Water Quality Improvement and Operation Stability

Urea as a hydrogen carrier: a perspective on its potential for safe, sustainable and long-term energy supply

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