Determination of the diffusion coefficient of hydrogen ion in hydrogels

Schuszter, Gábor; Gehér-Herczegh, Tünde; Szűcs, András; Tóth, Ágota; Horváth, Dezsö

doi:10.1039/c7cp00986k

Cited by 19 publications

(24 citation statements)

References 42 publications

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“…(5). Additionally, according to the literature, the diffusion coefficients of protons in water and gel are close to D water = 8.24 × 10 -3 (mm 2 /s), obtained by scaling the water interatomic potential model 22 , and D gel = 6.22 × 10 -3 (mm 2 /s), obtained from PFGSE-NMR spectroscopy 23 , respectively. Although the measured values in the present study yield slightly lower values than the above, the diffusion coefficient of protons can be estimated using the BTB agar gel method.…”

Section: The Reaction At the Corrosion Site (Anode)supporting

confidence: 69%

Visualization of aquaionic splitting via iron corrosion

Murakami

Zhang

Watanabe

2020

Sci Rep

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We report a water decomposition mode called 'Aquaionic Splitting (AiS)' by means of iron corrosion in aqueous solution. in this paper, we investigated the phenomenon by controlling the reaction between iron and water. A pseudo-sacrificial protection method with oil paint was employed to select the anode and cathode formation locations that govern iron corrosion. then, the AiS reaction was visualized by using BtB solution, whose colour corresponds to pH, to produce colour patterning that corresponds to the aquaion distribution. it has become clear that water can be selectively separated into protons and hydroxide ions by corrosion control treatment. In this vein, the diffusion coefficient of protons was estimated by using the colour patterning of BtB solution that accompanies iron corrosion, and aquaion distribution was then computer simulated by solving the diffusion equation. In metal corrosion in an aqueous solution, for example, iron corrosion in water, the formation of oxides and hydroxides is accompanied by the generation of local anodes and cathodes on the surface of a base material 1-4. Simultaneously, a substantial decomposition reaction of water occurs in conjunction with the corrosion reaction. It is well known that water electrolysis generates hydrogen gas and oxygen gas by the complete decomposition of water 5 (H 2 O → H 2 + 1/2 O 2) and that the generation of and hydroxide ions from water, that is, the aquaionic splitting (AiS) (H 2 O → H + + OH −) reaction of water, takes place as a cooperative reaction. In addition, it is noteworthy that the AiS reaction occurs at an energy of 0.83 eV as calculated by HSC Chemistry software (Outokumpu Research Oy, Pori, Finland), which is lower than the energy (1.23 eV) required for the complete electrolysis of water. Accordingly, we found similarities between the water decomposition reaction of electrolysis and the AiS reaction associated with iron corrosion. Generally, it is difficult to corrode a whole piece of iron in aqua because the oxidation/reduction reaction proceeds with random formation of the anode and the cathode. However, to observe a substantial water decomposition reaction, it is necessary to clearly distinguish and control the places where the oxidation and reduction reactions occur. Anticorrosion is then expected to control the corrosion location, and the plating method, which is a sacrificial anticorrosion method, is a well-known example 6,7. We focused on sacrificial protection in the present study. However, in addition to the need for preparation of the electrolyte in the plating method 8 , there are concerns about the introduction of impurities because other metals are used 9. Therefore, we adopted a facile corrosion protection method using a conductive oil-based paint, which is expected to have a pseudo-sacrificial effect, in addition to other similar proposed methods 10,11. By controlling the corrosion areas locally, we tried to observe the AiS reaction of water accompanying iron corrosion, which is visualized by using a bromothymol blue (BT...

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Section: The Reaction At the Corrosion Site (Anode)supporting

confidence: 69%

Visualization of aquaionic splitting via iron corrosion

Murakami

Zhang

Watanabe

2020

Sci Rep

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“…Propagating waves of pH and bistable switches have been obtained in the gel beads, but oscillations were not observed, probably because a key requirement is the differential transport (D H . D S ) of acid and substrate, and diffusion constants for acid in gels may be lower than for dilute solutions [43]. Evidence of collective behaviour has not yet been reported in urease beads.…”

Section: Discussionmentioning

confidence: 89%

Switches induced by quorum sensing in a model of enzyme-loaded microparticles

Bánsági¹,

Taylor²

2018

J. R. Soc. Interface.

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4Quorum sensing refers to the ability of bacteria and other single-celled organisms to respond to 5 changes in cell density or number with population-wide changes in behaviour. Here, simulations were 6 performed to investigate quorum sensing in groups of diffusively-coupled enzyme microparticles using 7 a well characterised autocatalytic reaction which raises the pH of the medium: hydrolysis of urea by 8 urease. The enzyme urease is found in both plants and microorganisms and has been widely exploited 9 in engineering processes. We demonstrate how increases in group size can be used to achieve a 10 sigmoidal switch in pH at high enzyme loading, oscillations in pH at intermediate enzyme loading and 11 a bistable, hysteretic switch at low enzyme loading. Thus, quorum sensing can be exploited to obtain 12 different types of response in the same system, depending on the enzyme concentration. The 13 implications for microorganisms in colonies are discussed and the results could help in the design of 14 synthetic quorum sensing for biotechnology applications such as drug delivery. 15 16

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“…Interestingly, Hermans, Besenius and co-workers recently reported that proton diffusion through agarose gels appeared to be faster than through other polymer gel networks, possibly as a result of its high polarity 11 – these results would support that view. There is increasing interest in the diffusion of H + through hydrogels, 26 and such issues, although of importance in reaction diffusion processes, are not yet fully understood.…”

Section: Resultsmentioning

confidence: 99%

“…Once again, this suggests that a supposedly 'inert' PG component can, nonetheless, inuence the dynamics of diffusion processes within gelswe note the importance of further studies in this important area. 26 Acid diffusion studiesoscillating gels…”

Section: Acid Diffusion Studiesexact Ph Determinationmentioning

confidence: 99%