The Theory of the Stick Antimony Electrode.

Parks, L. R.; Beard, H. C.

doi:10.1021/j150348a017

Cited by 5 publications

(4 citation statements)

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“…The electrode potential is generated by the reaction of the Sb2O3 layer with the H+ ions in the sample solution. Antimony electrodes can be used to reliably measure the pH in a range between 3 and 11 (Parks and Beard, 1933;Bates, 1961). The epoxy-body electrode is made of a rugged epoxy body and has a glass membrane formed in a spear shape, which served as the measuring tip.…”

Section: Measurement Setup and Proceduresmentioning

confidence: 99%

The effect of soil moisture content and soil texture on fast in situ pH measurements with two types of robust ion-selective electrodes

Vogel,

Emmerich,

Schröter

et al. 2023

Preprint

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Abstract. In situ soil pH measurements with ion-selective electrodes (ISE) receive increasing attention in soil mapping for precision agriculture, as they can avoid time consuming sampling and off-site laboratory work. However, unlike the standard laboratory protocol, in situ pH measurements are carried out at lower and varying soil moisture content (SMC), which can have a pronounced effect on the sensor readings. In addition, as the contact with the soil during in situ measurements should be relatively short, effects of soil texture could be expected, because texture controls the migration of protons to the electrode interface. This may be exacerbated by the fact that the electrodes used for in situ measurements are made of less sensitive but more robust materials as compared to the standard glass electrode. Therefore, the aim of the present study was to investigate the effect of soil moisture and soil texture on pH measurements using robust antimony and epoxy-body ISE pressed directly into the soil for 30 seconds. The SMC was gradually increased from dry conditions to field capacity. A wide range of soil texture classes were included with sand, silt and clay contents ranging from 16 to 91 %, 5 to 44 % and 4 to 65 % respectively. An exponential model was fitted to the data to quantify the relationship between SMC and pH. The results show that an increase in SMC causes a maximum increase in pH of approximately 1.5 pH units, regardless of the type of pH ISE used. Furthermore, for sandy soil textures, a rather linear relationship between pH and SMC was observed, whereas with decreasing mean particle diameter (MPD), the model had a pronounced exponential shape, i.e. a greater pH increase at low SMC and a plateau effect at high SMC. With increasing SMC, the pH values asymptotically approached the standard pH measured with a glass electrode in 0.01 M CaCl2 (soil:solution ratio = 1:2.5). Thus, at high SMC, subsequent calibration of the sensor pH values to the standard pH value is negligible, which may be relevant for using the sensor pH data for lime requirement estimates. The pH measurement error decreases exponentially with increasing soil moisture and increases with decreasing MPD. Using a knee point detection, reliable pH values were obtained for SMC > 11%, irrespective of the pH ISE used. An analysis of the regression coefficients of the fitted exponential model showed that the maximum pH increase also depends on soil texture, i.e. the influence of soil moisture variation on the pH value increases with decreasing MPD. Moreover, the concavity of the exponential curve increases with decreasing MPD.

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Section: Measurement Setup and Proceduresmentioning

confidence: 99%

The effect of soil moisture content and soil texture on fast in situ pH measurements with two types of robust ion-selective electrodes

Vogel,

Emmerich,

Schröter

et al. 2023

Preprint

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show abstract

“…Equation [14] shows that OE e 0 pH = --0.060V and OEe --0.020V 0 log [Sb (III) ] in accord with the experimental results (Eq. [5] and [6]). The values of E e calculated for Eq.…”

Section: Ee = E O + (Rt/3f) In [Hsbo2] + (Rt/f) In [H+] V [19]mentioning

confidence: 99%

“…Park and Beard (4,5) surmised that the rest potential of antimony was determined by the redox reaction 2Sb -5 3H20 = Sb203 -5 6H + -5 6e- [1] with the equilibrium potential following the relation E e = 0.152 --0.059 pH, volts [2] The Sb2Oz was assumed to be a surface film on the antimony electrode and formed antimonyl ions (SbO +) in strong acid solutions by the reaction Sb203 -5 2H + = 2SbO + -5 H20 [3] Although Bishop and Short (6) and Stock, Purdy, and Garcia (2) obtained the same redox potential, they attributed it to different reaction steps. Bishop and Short (6) suggested Sb(OH)3 as an intermediate, while Stock, Purdy, and Garcia (2) suggested Sb +3 as an intermediate.…”

Section: Ie Tied : ~'C Dep[ H+ ] [Sb (Iii) ]E -Fei2rtmentioning

confidence: 99%

“…Zn + + e--~ Zn Although the reaction mechanism of the electrocrystallization of zinc is still a matter for discussion, it now seems accepted that the adsorption of hydrogen plays an important role in acidic medium As a matter of fact, hydrogen evolution takes place within the same potential range as for zinc deposition (6) and it is known that hydrogen is always present in zinc electrodeposited from acid solutions (7). In addition, the polarization curve which characterizes the electrocrystallization of this metal considerably depends on the electrolyte pH (5,8,9) In very alkaline medium, the electrolytic deposition of zinc is known to occur mainly from zincate ions [Zn(OH)4] 2-(10-12). In addition, it is generally accepted that charge transfer occurs in several steps, but the mechanism of the over-all reaction [Zn(OH)4] 2--+ ~e---> Zn + 4OHis still under discussion.…”

Section: Zn 2 + + E--> Zn +mentioning

confidence: 99%

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Electrode Kinetics of Antimony in Acidic Chloride Solutions

Wikstrom

Thomas

Nobe

1975

J. Electrochem. Soc.

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The kinetics of the electrode processes of antimony in normalKCl‐normalHCl solutions have been investigated. The rest potential of antimony in acidic chloride solutions can be expressed empirically by the equationEnormale=0.182−0.060 pH+0.020log][normalSb)(IIIand is attributed to the redox reactionnormalSb+2H2O=HSbO2+3H++3eThe empirical rate equations for the electrodissolution and electroreduction reactions near the rest potential areInormala=k̅normala][OH−SbIII−1e2FE/RTandInormalc=k̅normalcH+2e−FE/RTThe rate of electrodeposition of Sb(III) can be expressed asInormalc,normaldep=k̅normalc,normaldep][H+][normalSb)(IIIe−FE/2RTA mechanism which is consistent with the experimental results is proposed.

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Notes on the determination of the alkalinity of soap solutions

Preston

1937

Oil Soap

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The Theory of the Stick Antimony Electrode.

Cited by 5 publications

References 0 publications

The effect of soil moisture content and soil texture on fast in situ pH measurements with two types of robust ion-selective electrodes

The effect of soil moisture content and soil texture on fast in situ pH measurements with two types of robust ion-selective electrodes

Electrode Kinetics of Antimony in Acidic Chloride Solutions

Notes on the determination of the alkalinity of soap solutions

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