Effect of Solution Composition on the Energy Production by Capacitive Mixing in Membrane-Electrode Assembly

The final edited version of the paper can be found at: http://pubs.acs.org/articlesonrequest/AOR-c9UMxSzGY3eiU5SENNgT The complete citation is: Ahualli, S.; et al. Effect of Solution Composition on the Energy Production by Capacitive Mixing in Membrane-Electrode Assembly. Journal of Physical Chemistry, 118(29): 15590-15599 (2014). DOI:10.1021/jp504461mOpen access in the Journal on May 26, 2015In this work we consider the extent to which the presence of multi-valent ions in solution modifies the equilibrium and dynamics of the energy production in a capacitive cell built with ion-exchange membranes in contact with high surface area electrodes. The cell potential in open circuit (OCV) is controlled by the difference between both membrane potentials, simulated as constant volume charge regions. A theoretical model is elaborated for steady state OCV, first in the case of monovalent solutions, as a reference. This is compared to the results in multi-ionic systems, containing divalent cations in concentrations similar to those in real sea water. It is found that the OCV is reduced by about 25 % (as compared to the results in pure NaCl solutions) due to the presence of the divalent ions, even in low concentrations. Interestingly, this can be related to the “uphill” transport of such ions against their concentration gradients. On the contrary, their effect on the dynamics of the cell potential is negligible in the case of highly charged membranes. The comparison between model predictions and experimental results shows a very satisfactory agreement, and gives clues for the practical application of these recently introduced energy production methods.The research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under agreement No. 256868. Further financial support from Junta de Andalucia, Spain (PE2012-FQM 694) is also acknowledged. One of us, M.M.F., received financial support throughan FPU grant from the Universityof Granada

Temperature effects on energy production by salinity exchange

This is an unedited version of this paper. The publisher version can be reached in this URL: http://pubs.acs.org/doi/abs/10.1021/es500634fIn recent years, the capacitance of the interface between charged electrodes and ionic solutions (the electric double layer) has been investigated as a source of clean energy. Charge is placed on the electrodes either by means of ion-exchange membranes or of an external power source. In the latter method, net energy is produced by simple solution exchange in open circuit, due to the associated decrease in the capacitance of the electric double layer. In this work, we consider the change in capacitance associated with temperature variations: the former decreases when temperature is raised, and, hence, a cycle is possible in which some charge is put on the electrode at a certain potential and returned at a higher one. We demonstrate experimentally that it is thus viable to obtain energy from electric double layers if these are successively contacted with water at different temperatures. In addition, we show theoretically and experimentally that temperature and salinity variations can be conveniently combined to maximize the electrode potential increase. The resulting available energy is also estimated.Departamento de Física AplicadaThe research leading to these results received funding from the European Union 7th Frame-work Programme (FP7/2007-2013) under agreement No. 256868. Further Financial supports from Junta de Andalucía, project FQM 694, and Ministerio de Economía y Competitividad (Spain), project FIS2013-47666-C3-1-R

Ecology and application of haloalkaliphilic anaerobic microbial communities

Haloalkaliphilic microorganisms that grow optimally at high-pH and high-salinity conditions can be found in natural environments such as soda lakes. These globally spread lakes harbour interesting anaerobic microorganisms that have the potential of being applied in existing technologies or create new opportunities. In this review, we discuss the potential application of haloalkaliphilic anaerobic microbial communities in the fermentation of lignocellulosic feedstocks material subjected to an alkaline pre-treatment, methane production and sulfur removal technology. Also, the general advantages of operation at haloalkaline conditions, such as low volatile fatty acid and sulfide toxicity, are addressed. Finally, an outlook into the main challenges like ammonia toxicity and lack of aggregation is provided.This work was performed in the TTIW- cooperation framework of Wetsus, European Centre of Excel- lence for Sustainable Water Technology (www.wetsus.nl). Wetsus is funded by the Dutch Ministry of Economic Affairs, the European Union Regional Development Fund, the Province of Fryslân, the City of Leeuwarden and the EZ/Kompas program of the“ Samenwerkingsverband Noord-Nederland”. The authors would like to thank the participants of the research theme "Sulfur", namely Paqell, for fruitful discussions and financial suppor

Experiences of parents to children with congenital heart defects : A literature study

Bakgrund: Varje år föds 1 % av alla barn i Sverige med medfött hjärtfel. Barnet med denna diagnos och dess föräldrar är i stort behov av omvårdnad. Viktiga komponenter i denna omvårdnad är stöd och uppmuntran, information på rätt nivå för mottagaren och att frågor blir besvarade. Föräldrar till barn med medfött hjärtfel lider i större mån än andra föräldrar av någon form av psykosocial stress eller ångest relaterat till barnets diagnos. Syfte: Syftet var att beskriva föräldrars upplevelser av att ha barn med medfödda hjärtfel. Metod: En litteraturstudie baserad på kvalitativa vetenskapliga artiklar. Artiklarna hittades via sökningar i CINAHL Complete, MEDLINE, Academic Search Elite och CINAHL with Full Text där tio artiklar inkluderades efter kvalitetsgranskning. Resultat: I studiens analys av artiklarna framkom fyra teman som präglade föräldrarnas upplevelser under barnens uppväxt. Dessa var; känslan av otillräcklighet och osäkerhet, en ny komplex situation, stress samt stöd och tillit. Slutsats: När ett barn får diagnosen medfött hjärtfel står hela familjen inför en ny situation som innebär stora omställningar i vardagen. Stress var en konstant börda och föräldrarna upplevde att de kände sig otillräckliga och osäkra i föräldrarollen. Behovet av stöd och tillit, från både vårdpersonal, släkt och vänner, var stort för att orka med situationen. Klinisk betydelse: Resultatet i denna litteraturstudie kan bidra med kunskap om föräldrars upplevelser av att ha ett barn med medfött hjärtfel. Studien kan medvetandegöra behoven hos denna grupp föräldrar, vilket kan vara till hjälp för utformning av riktlinjer inom denna ram för omvårdnad.Background: Each year, 1% of all children born in Sweden are diagnosed at birth with congenital heart defects. The child with this diagnosis and its parents are in great need of care. Key components of this care are support and encouragement, information given at the right level for the receiver, and making sure that questions are answered. Parents of children with congenital heart disease suffer to a greater extent than other parents from some form of psychosocial stress or anxiety related to their child's diagnosis. Aim: The aim of this study was to describe parents' experiences of having children with congenital heart defects. Method: A literature study based on qualitative scientific articles. The articles were found through the databases CINAHL Complete, MEDLINE, Academic Search Elite and CINAHL with Full Text and ten articles were included after quality control. Findings: The study's analysis of the articles revealed four themes that characterized the parents' experiences as the children grew. These were; feeling of inadequacy and insecurity, new complex situation, stress, and also support and trust. Conclusion: In the new situation in which a child where diagnosed with congenital heart defect, the whole family underwent major changes in everyday life. Stress was a constant burden and parents experienced inadequacy and insecurity in the parental role. The need for support and trust from both health care workers, friends and, family was great when dealing with the situation. Relevance to clinical practice: The results of this study will hopefully contribute knowledge about parents' experiences of having a child with congenital heart defects. The study may sensitize the needs of this group of parents, which can be helpful for the development of guidelines within this framework of nursing care

Inhibition of a biological sulfide oxidation under haloalkaline conditions by thiols and diorgano polysulfanes

A novel approach has been developed for the simultaneous description of reaction kinetics to describe the formation of polysulfide and sulfate anions from the biological oxidation of hydrogen sulfide (H2S) using a quick, sulfide-dependent respiration test. Next to H2S, thiols are commonly present in sour gas streams. We investigated the inhibition mode and the corresponding inhibition constants of six thiols and the corresponding diorgano polysulfanes on the biological oxidation of H2S. A linear relationship was found between the calculated IC50 values and the lipophilicity of the inhibitors. Moreover, a mathematical model was proposed to estimate the biomass activity in the absence and presence of sulfurous inhibitors. The biomass used in the respiration tests originated from a full-scale biodesulfurization reactor. A microbial community analysis of this biomass revealed that two groups of microorganism are abundant, viz. Ectothiorhodospiraceae and Piscirickettsiaceae.Accepted Author ManuscriptBT/Environmental Biotechnolog

Effect of Methanethiol Concentration on Sulfur Production in Biological Desulfurization Systems under Haloalkaline Conditions

Bioremoval of H₂S from gas streams became popular in recent years because of high process efficiency and low operational costs. To expand the scope of these processes to gas streams containing volatile organic sulfur compounds, like thiols, it is necessary to provide new insights into their impact on overall biodesulfurization process. Published data on the effect of thiols on biodesulfurization processes are scarce. In this study, we investigated the effect of methanethiol on the selectivity for sulfur production in a bioreactor integrated with a gas absorber. This is the first time that the inhibition of biological sulfur formation by methanethiol is investigated. In our reactor system, inhibition of sulfur production started to occur at a methanethiol loading rate of 0.3 mmol L^–1 d^–1. The experimental results were also described by a mathematical model that includes recent findings on the mode of biomass inhibition by methanethiol. We also found that the negative effect of methanethiol can be mitigated by lowering the salinity of the bioreactor medium. Furthermore, we developed a novel approach to measure the biological activity by sulfide measurements using UV-spectrophotometry. On the basis of this measurement method, it is possible to accurately estimate the unknown kinetic parameters in the mathematical model