Effect of ionic strength on the formal potential of the glass electrode in various saline media

Brandariz, Isabel; Vilariño, Teresa; Alonso, Pablo Otero; Herrero, Roberto; Fiol, Sarah; Vicente, Manuel E. Sastre de

doi:10.1016/s0039-9140(98)00022-8

Cited by 26 publications

(31 citation statements)

References 17 publications

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“…The glass electrode was calibrated in solutions of known proton concentration at a constant ionic strength following the procedure described elsewhere (Brandariz et al, 1998;Fiol et al, 1992). The electrodes were calibrated in the acid pH range, slopes were within 4% of the theoretical Nernst value, and coefficients of determination (r 2 ) for the Nernst type equation were always greater than 0.9999.…”

Section: Potentiometric Titrations Of the Biomass Samplesmentioning

confidence: 99%

Physicochemical studies of Cadmium(II) biosorption by the invasive alga in Europe, Sargassum muticum

Lodeiro

Cordero

Grille

et al. 2004

Biotech & Bioengineering

121

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In recent years, there has been a significant increase in the studies concerning brown seaweed as biosorbents for metal removal owing to their high binding ability and low cost. This work reports the results of a study regarding the cadmium binding equilibria of dead biomass from the seaweed Sargassum muticum; this alga is a pest fouling organism that competes with the local fucalean species and may also interfere with the "sea industry"; therefore, it would constitute an ideal material to be used as biosorbent. Seven different treatments were tested in order to obtain a stable biomass that could be suitable for industrial use under a broad range of operational conditions. The treatments employed were protonation, chemical cross-linking with formaldehyde, KOH, Ca(OH)(2) and CaCl(2) or physical treatments with acetone and methanol. The equilibrium adsorption isotherms of Langmuir, Freundlich, and Langmuir-Freundlich were obtained for the quantitative description of the cadmium uptake. The effect of pH on biosorption equilibrium was studied at values ranging from 1 to 6, demonstrating the importance of this parameter for an accurate evaluation of the biosorption process. Maximum biosorption was found pH higher than 4.5. The maximum biosorption uptake for the raw biomass was 65 mg g(-1), while for formaldehyde cross-linking biomass the uptake increases to 99 mg g(-1) and for protonated biomass to 95 mg g(-1). Potentiometric titrations were carried out to estimate the total number of weak acid groups and to obtain their apparent pK value, 3.85, using the Katchalsky model. Kinetic studies varying cadmium concentration, algal dose, and ionic strength were carried out. Over 95% of the maximum cadmium uptake was achieved within 45 min, so the process can be considered relatively fast. A pseudo-second-order model, for the kinetics of cadmium biosorption, was shown to be able to reproduce experimental data points with accuracy.

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Section: Potentiometric Titrations Of the Biomass Samplesmentioning

confidence: 99%

Physicochemical studies of Cadmium(II) biosorption by the invasive alga in Europe, Sargassum muticum

Lodeiro

Cordero

Grille

et al. 2004

Biotech & Bioengineering

121

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“…I will show the dependence of the liquid junction potential with the ionic strength of the solution. Two different behaviors can be seen:-In electrode A a linear relationship is found.Table 2lists the slopes obtained in a linear fit at 15, 25 and 35 C and at 25 C with a similar electrode, electrode B, taken from[17]. Slopes show a good agreement, taking into account the error obtained in the fitting, as could be expected when electrodes with a similar liquid junction connection, e.g., porous pin, Dependence of E rep with ionic strength for two different electrodes; temperature 25 C and KCl as background electrolyte.…”

mentioning

confidence: 61%

“…I (M) together with the calculated curve of s log y H þ ext vs. I (M), where y is the activity coefficient in the molarity scale [17]. The curve has been shifted 396.4 mV along the vertical axes, which corresponds to the constants that appear in Equation 5, viz.…”

Section: Methodsmentioning

confidence: 99%

“…f g , B and B 0 are functions depending on the ionic strength and they have the usual meaning given in Pitzer equations [15,17]; C, y and c are interaction parameters for different ions. Substituting B and B 0 in the expression for the logarithm of the activity coefficient of H þ ion yields: P, Q, R and T are thus constants that depend on the particular inert electrolyte [15].…”

Section: Appendixmentioning

confidence: 99%

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Estimating the Change in Liquid Junction Potential on Glass Electrodes

et al. 2001

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“…This means that the ionic strength of the reaction mixture is high (approximately 0.5 mol L -1 ). Ionic strength can affect the pH electrode liquid junction potential and the hydrogen ion activity [14,15]. The large excess of I -will also affect the dissociation of HI.…”

Section: Determination Of Relationship Between Ph Measured and Hi Prementioning

confidence: 99%

The effect of using a methanol–water solvent mixture on pH oscillations in the palladium-catalyzed phenylacetylene oxidative carbonylation reaction

Parker

Novakovic

2017

Reac Kinet Mech Cat

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The palladium-catalyzed phenylacetylene oxidative carbonylation reaction has been shown to produce regular oscillations in pH, reaction heat, and turbidity when conducted in batch with methanol as solvent. Previous studies of the catalytic system showed that water plays an important role in the behavior of the catalytic cycle. Investigating this role further, the reaction was performed in methanol-water mixtures. Experiments demonstrated that, under the conditions studied, oscillations in pH are feasible when the water concentration in the system is increased (0-30 V%). At the same time oscillations visually changed, being transformed from regular oscillations to more stepwise behavior as the proportion of water is increased. By establishing the relationship between the recorded pH and HI concentration it was found that increased water concentration suppresses HI formation and hence slows the autocatalysis in the reaction. It was also found that oscillations begin when the HI concentration is in the region of 1 9 10 -3 mol L -1 . Additionally, as the amount of water in the system increases a slight decrease in the concentration of HI when oscillations start was noted.

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Effect of ionic strength on the formal potential of the glass electrode in various saline media

Cited by 26 publications

References 17 publications

Physicochemical studies of Cadmium(II) biosorption by the invasive alga in Europe, Sargassum muticum

Physicochemical studies of Cadmium(II) biosorption by the invasive alga in Europe, Sargassum muticum

Estimating the Change in Liquid Junction Potential on Glass Electrodes

The effect of using a methanol–water solvent mixture on pH oscillations in the palladium-catalyzed phenylacetylene oxidative carbonylation reaction

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