Determination of the performance of glass electrodes in aqueous solutions in the physiological ph range and at the physiological sodium ion concentration

1982 ◽  
Vol 139 ◽  
pp. 53-59 ◽  
Author(s):  
R. Sprokholt ◽  
A.H.J. Mass ◽  
M.J. Rebelo ◽  
A.K. Covington
Keyword(s):  
Aqueous Solutions ◽  
Sodium Ion ◽  
Ion Concentration ◽  
Glass Electrodes ◽  
Ph Range

Adsorption of sodium cyclododecylmethanoate and cycloundecylmethanoate at the air/water interface

1984 ◽  
Vol 62 (11) ◽  
pp. 2359-2363 ◽  
Author(s):  
Jan J. Spitzer
Keyword(s):  
Aqueous Solutions ◽  
Sodium Ion ◽  
Ion Concentration ◽  
Ionic Surfactants ◽  
Free Energies ◽  
Straight Chain ◽  
Double Chain ◽  
Adsorbed State ◽  
Critical Micelle Concentrations ◽  
Air Water Interface

Surface tension measurements on aqueous solutions of sodium cyclododecylmethanoate and sodium cycloundecylmethanoate in sodium carbonate/bicarbonate buffers and at constant sodium ion concentration at 25 °C were used to obtain the standard free energies of adsorption, the saturation areas per surfactant ion, and the critical "micelle" concentrations of these compounds. Similar measurements were done for solutions of sodium dodecanoate for comparisons.The standard free energies of adsorption of CH2 group that is located in a macrocyclic cycloalkyl ring appears to follow the "rule of two" (−RT ln 2) that is also valid for straight chain ionic surfactants. The saturation areas of both cyclododecylmethanoate and cycloundecylmethanoate are about 52 Å2/ion as compared to about 32 Å2/ion for normal dodecanoate.For large ring cycloalkylmethanoates the critical "micelle" concentrations appear to decrease by a factor of about 4/5 for each CH2 group added to the ring as compared to the factor of about 1/2 for each CH2 group added to the chain of normal alkanoates. The data suggest that large cycloalkyl rings have "collapsed ring", or "double chain", conformation in aqueous solutions and in the adsorbed state.

scholarly journals A Novel Potentiometric Sensor for Determination of Nitrate ion based on N, N’- Ethylene-bis-(Salicylideneaminato) copper (II)

2021 ◽  
Vol 16 (3) ◽  
Author(s):  
Mohsin Ali ◽  
Jitendra Singh
Keyword(s):  
Selectivity Coefficient ◽  
Dioctyl Phthalate ◽  
Polymeric Films ◽  
Ion Concentration ◽  
Membrane Composition ◽  
Ion Sensors ◽  
Nitrate Ion ◽  
Ph Range ◽  
The One

Ionophore N, N’–Ethylene-bis-(Salicylideneaminato) copper (II) has been synthesized and characterized by IR and 1H NMR spectroscopy. Poly (vinyl chloride) based polymeric films of this ionophore along with cation discriminator (CTAB) and different plasticizers (dibutyl phthalate, dioctyl phthalate, 1-chloronapthalene and tri-n-butyl phosphate) were prepared and investigated as Nitrate ion sensors. Among all the different sensors fabricated, the one with membrane composition as I (7 mg): PVC (31 mg): DBP (60 mg): CTAB (2 mg) exhibited best characteristics. This sensor functions admirably over a wide concentration range 1.0×10−6–1.0×10−2 M with Nernstian compliance (59.8 mV per decade of concentration) between pH range 2.5–9.2 with a rapid response time of 13s. The sensor showed a lower detection limit 1.58×10-6 M. The selectivity coefficient values as determined by the fixed interfering method (FIM) show that the Nitrate ion has excellent selectivity over several anions. The sensor shows satisfactory time span of 2 months with great reproducibility while used continuously daily for 4 hrs. The sensor has been successfully utilized in the determination of nitrate ion concentration in different water samples.

Effect of particle size and sodium ion concentration on anaerobic thermophilic food waste digestion

2000 ◽  
Vol 41 (3) ◽  
pp. 67-73 ◽  
Author(s):  
I.S. Kim ◽  
D.H. Kim ◽  
S-H. Hyun
Keyword(s):  
Particle Size ◽  
Food Waste ◽  
Substrate Utilization ◽  
Sodium Ion ◽  
Ion Concentration ◽  
Utilization Rate ◽  
Average Particle ◽  
Organic Loading ◽  
Kinetic Coefficients

Serial basic tests were conducted for the determination of fundamental kinetics and for the actual application of kinetic parameters to food waste digestion with precise measurement of methane production. The effects of food particle size and sodium ion concentration on the anaerobic thermophilic food waste digestion process were investigated. Results of serial tests for the determination of fundamental kinetic coefficients showed the value of k (maximum substrate utilization rate coefficient) and KS (half-saturation coefficient) as 0.24 hr−1 and 700 mg/L, respectively, for non-inhibiting organic loading range. The substrate inhibition coefficient (Ki) was 1000 mg/L for inhibiting organic loading range. No inhibition effect was shown until 5g/L of sodium ion concentration was applied to the serum bottle reactor. However, the volume of methane gas was decreased gradually to the concentrations of more than 5 g/L of sodium ion applied. All sizes of food waste particle had the same constants (A:0.45) but the maximum substrate utilization rate constant (kHA) was inversely proportional to particle size. As average particle size increased from 1.02 mm to 2.14 mm, kHA decreased from 0.0033 hr−1 to 0.0015 hr−1. Result reveals that particle size is one of the most important factors in anaerobic food waste digestion.

Nickel ion removal from aqueous solutions through the adsorption process: a review

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammadtaghi Vakili ◽  
Mohd Rafatullah ◽  
Jing Yuan ◽  
Haider M. Zwain ◽  
Amin Mojiri ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Metal Ion ◽  
Adsorption Process ◽  
Negative Impact ◽  
Ion Concentration ◽  
Nickel Ion ◽  
Nickel Ions ◽  
Desorption Mechanism ◽  
Ph Range ◽  
Nickel Adsorption

AbstractRecently, removal of nickel ions has been gaining a lot of attention because of the negative impact of nickel ions on the environment. The aim of this review paper is to organize the scattered available information on removal of nickel ions from aqueous solutions through the adsorption process. Survey on investigated materials suggests that composite- and polymer-based adsorbents have the most effective capability for nickel adsorption. The composite material class, i.e. CaCO3-maltose, followed by biopolymer-based material showed the highest Ni(II) adsorption capacity of 769.23 and 500 mg/g, respectively. The importance of treatment parameters (i.e. pH, temperature, contact time, and metal ion concentration) is discussed, together with their effect on the underlying physicochemical phenomena, giving particular attention to the adsorption/desorption mechanism. It was ascertained that adsorption of nickel ions is pH dependent and the optimal pH range for adsorption of Ni(II) ions was in range of 6–8. In general, nickel adsorption is an endothermic and spontaneous process that mainly occurs by forming a monolayer on the adsorbent (experimental data are often fitted by Langmuir isotherms and pseudo-second-order kinetics). Regeneration (i.e. desorption) is also reviewed, suggesting that acidic eluents (e.g. HCl and HNO3) allow, in most of the cases, an efficacious spent adsorbent recovery. The percentage use of desorption agents followed the order of acids (77%) > chelators (8.5%) > alkalis (8%) > salts (4.5%) > water (2%). Helpful information about adsorption and desorption of nickel ions from aqueous solutions is provided.

Potentiometric Determination of Trace Amounts of Aluminium Utilizing Polyvinyl Chloride Membrane and Coated Platinum Sensors Based on E-N′-(2-Hydroxy-3-methoxybenzylidene) benzohydrazide

2013 ◽  
Vol 96 (1) ◽  
pp. 204-211 ◽  
Author(s):  
Somayeh Tajik ◽  
Mohammad Ali Taher ◽  
Iran Sheikhshoaie
Keyword(s):  
Polyvinyl Chloride ◽  
Tap Water ◽  
Direct Determination ◽  
Ion Concentration ◽  
Nonaqueous Media ◽  
Wide Range ◽  
And Performance ◽  
Ph Range ◽  
Polyvinyl Chloride Membrane

Abstract This paper describes the construction and performance characteristics of novel polyvinyl chloride membrane (PME) and coated platinum (CPtE) aluminium (Al) ion selective electrodes based on E-N′-(2-hydroxy-3-methoxybenzylidene) benzohydrazide. The electrodes exhibited linear responses with near Nernstian slopes of 19.9 ± 0.3 (PME) and 20.1 ± 0.4 (CPtE) mV/decade of activity within the Al3+ ion concentration range of 3.0 × 10–7 to 1.0 × 10–2 M for the PME and 1.0 × 10–7 –1.0 × 10–2 M for the CPtE. These sensors were applicable in a pH range of 3.0 to 7.0. The LODs of the PME and CPtE were 1.7 × 10–7 and 5.6 × 10–8 M, respectively. They had a response time of less than 10 s and could be used practically for a period of at least 2 months without measurable divergence in results. The isothermal temperature coefficient of the PME was 1.12 × 10–3 V/°C, and it can tolerate partially nonaqueous media up to 25%. The electrodes showed excellent selectivity towards Al3+ ions in the presence of a wide range of alkali, alkaline earth, and transition metals ions. They were successfully applied for the direct determination of Al3+ ions in tap water, aqueduct water, mineral water, and Al–Mg syrup and as indicator electrodes in potentiometric titration of Al ions with EDTA.

Fluctuations of Annual Precipitation and Water Resources Quality in Ukraine

2016 ◽  
Vol 10 (4s) ◽  
pp. 621-629
Author(s):  
Valentina Pidlisnyuk ◽  
◽  
John Harrington JR ◽  
Yulia Melnyk ◽  
Yuliya Vystavna ◽  
...  
Keyword(s):  
Water Resources ◽  
Surface Waters ◽  
Precipitation Amount ◽  
Ion Concentration ◽  
Annual Precipitation ◽  
Resource Quality ◽  
Phosphate Ion ◽  
Regional Trends

The article focuses on examining the influence of fluctuations in annual precipitation amount on the quality of surface waters. Water quality was estimated with data on BOD, COD and phosphate–ion concentration within five selected regions of Ukraine. Analysis of the precipitation data (1991 – 2010) showed different regional trends. Using the statistics, determination of the interconnection between precipitation amount and water resources quality were done. The obtained regularities and associated uncertainties can be used for prediction of changes in water resource quality and as a guide for future adaptation to possible climate change.

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

Residual phase lignin in haft cooking related to the conditions in the cook

1997 ◽  
Vol 12 (4) ◽  
pp. 225-229
Author(s):  
Cart-in A-S. Gustavsson ◽  
Chritofer T. Lindgren ◽  
Mikael E. Lindström
Keyword(s):  
Hydrogen Sulfide ◽  
Ionic Strength ◽  
Sodium Ion ◽  
Ion Concentration ◽  
Constant Composition ◽  
Hydroxide Ion ◽  
Sulfide Ion ◽  
Residual Phase ◽  
Kraft Cooking ◽  
Very High

Abstract The amount of lignin reacting according to the slow residual phase, i.e. the residual phase lignin, is in many perspectives an interesting issue. The purpose of the present investigation was to develop a mathematical model to show how the amount of residual phase lignin in the kraft cooking of spruce chips (Picm ahies) depends on the conditions in the earlier phases of the cook. The variables studied were hydroxide ion concentration, hydrogen sulfide ion concentration and ionic strength. The liquor-to-wood ratio during pulping was very high to maintain approximately constant chemical concentrations throughout each experiment (so called "constant composition" cooks). An increase in hydroxide ion concentration andtor hydrogen sulfide ion concentration leads to a decrease in the amount of residual phase lignin, while an increase in ionic strength, i.e. sodium ion concentration, leads to an increase. A signiticant result is that the hydrogen sulfide ion concentration has a pronounced influence on the amount of residual phase lignin during a cook at a low hydroxide ion concentration. The amount of residual phase lignin expressed as % lignin on wood, L,, can be described by the following equation developed for "constant composition" cooks (when cooking with a constant sodium ion concentration of 2 mol/L): LT=0,55-0.32*[HO-](-1,3)*ln[HS-] This equation is valid for a concentration of HO- in the range from 0.17 to 1.4, and a hydrogen sulfide ion concentration from 0.07 to 0.6 mol/L.

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