Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb OXIN, Ostsorb DETA, and Ostsorb DTTA

1994 ◽  
Vol 59 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
Ladislav Svoboda ◽  
Petr Vořechovský
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Sodium Perchlorate ◽  
Exchange Capacity ◽  
Chloride Ions ◽  
Point Of View ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Acidic Media ◽  
Cadmium And Lead

The properties of cellulose chelating ion exchangers Ostsorb have been studied in the sorption of cadmium and lead from aqueous solutions. The Cd(II) and Pb(II) ions are trapped by the Ostsorb OXIN and Ostsorb DETA ion exchangers most effectively in neutral and alkaline media but at these conditions formation of stable hydrolytic products of both metals competes with the exchange equilibria. From this point of view, Ostsorb DTTA appears to be a more suitable sorbent since it traps the Pb(II) and Cd(II) ions in acidic media already. Chloride ions interfere with the sorption of the two metals by Ostsorb DTTA whereas the ionic strength adjusted by the addition of sodium perchlorate does not affect the exchange capacity of this ion exchanger.

Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb DITHIZON and Ostsorb SALICYL

1994 ◽  
Vol 59 (6) ◽  
pp. 1319-1325 ◽  
Author(s):  
Ladislav Svoboda ◽  
Stanislav Jech
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Exchange Capacity ◽  
Ion Exchanger ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Metal Concentrations ◽  
Cadmium And Lead

The pH and I (ionic strength) dependences of exchange capacity of chelating ion exchangers Ostsorb based on spherical cellulose modified with functional groups of dithizone and salicylic acid have been studied in the sorption of Pb(II) and Cd(II) ions. The cellulosic selective sorbents Ostsorb DITHIZON and Ostsorb SALICYL can be used for sorption of Pb(II) and Cd(II) ions from aqueous solutions of I = 0 - 1 mol l-1 (Pb) and I = 0 - 5 mol l-1 (Cd); the dithizone ion exchanger retains both metals most effectively at pH 7 - 8, the salicyl ion exchanger at pH 5.5 - 6.5 (Pb) or pH 4 - 9 (Cd). Because of the formation of precipitates of hydrolytic products of the two metals in neutral and alkaline media, it is suitable to carry out the sorption in media of mild acidity if possible, particularly so at the metal concentrations above 1 mg l-1. Increasing ionic strength affects the exchange capacity for both metals in a negative way.

Effect of Chloride Ions on the Hydrolysis of Trivalent Lanthanum, Praseodymium and Lutetium in Aqueous Solutions of 2 M Ionic Strength

2005 ◽  
Vol 34 (4) ◽  
pp. 427-441 ◽  
Author(s):  
H. López-González ◽  
M. Solache-Ríos ◽  
M. Jiménez-Reyes ◽  
J. J. Ramírez-García ◽  
A. Rojas-Hernández
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Chloride Ions ◽  
Hydrolysis Of

Free radical mechanisms for the oxidation of 2,3-dihydroxy-2-propenal (triose reductone) by hexacyanoferrate(III)

1985 ◽  
Vol 63 (5) ◽  
pp. 1005-1008 ◽  
Author(s):  
Yasuo Abe ◽  
Takaaki Dohmaru ◽  
Hideo Horii ◽  
Setsuo Taniguchi
Keyword(s):  
Free Radical ◽  
Ionic Strength ◽  
Rate Constants ◽  
Sodium Perchlorate ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Second Order ◽  
Probable Mechanism ◽  
Acidic Media ◽  
The Media

Kinetic studies of the oxidation of 2,3-dihydroxy-2-propenal (triose reductone, RH2) by hexacyanoferrate(III), [Fe(CN)6]3−, were carried out in acidic media ([H+] = 0.02–0.1 M (1 M = 1 mol dm−3)) at various temperatures (10–30° C). The ionic strength of the media (I = 0.04–0.4 M) was adjusted using sodium perchlorate. The second-order rate constants in M−1 s−1 are (0.86 ± 0.06) – (2.83 ± 0.14) for the reactions of hexacyanoferrate(III) with RH2, and [(4.16 ± 0.03) − (12.4 ± 0.2)] × 103 for those with RH− ion. Activation parameters for the oxidation have been reported and compared with those of the oxidation of triose reductone with peroxodisulfate ion. A probable mechanism is proposed for the reaction.

The Electroreduction of Periodate Anion in Alkaline Media

1971 ◽  
Vol 49 (16) ◽  
pp. 2657-2663 ◽  
Author(s):  
W. R. Fawcett ◽  
Y. C. Kuo Lee
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Double Layer ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Alkaline Media ◽  
Dropping Mercury Electrode ◽  
Ph Range ◽  
Theoretical Developments

The electroreduction of periodate anion was studied at a dropping mercury electrode in aqueous solutions in the pH range 11–13.3 where the process is markedly affected by the double layer. The electrode reaction was found to be complex, its mechanism depending on both pH and ionic strength. The effects of the double layer on the component reactions are discussed with respect to current theoretical developments.

scholarly journals Natural diatomite (Rudovci, Serbia) as adsorbent for removal Cs from radioactive waste liquids

2015 ◽  
Vol 47 (3) ◽  
pp. 299-309 ◽  
Author(s):  
S. Nenadovic ◽  
Lj. Kljajevic ◽  
S. Markovic ◽  
M. Omerasevic ◽  
U. Jovanovic ◽  
...  
Keyword(s):  
Cation Exchange Capacity ◽  
Emission Spectroscopy ◽  
Atomic Emission ◽  
Exchange Capacity ◽  
Alkaline Media ◽  
X Ray Diffraction ◽  
Acidic Media ◽  
X Ray ◽  
As Adsorption ◽  
Acidic And Alkaline Media

The removal of Cs (I) ions from aqueous solution was studied using natural diatomite as adsorption materials originated from Rudovci, Serbia. The microstructure of natural diatomite has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) while the degree of Cs adsorption was evaluated by atomic emission spectroscopy. The cation exchange capacity (CEC) values for natural diatomite was 50 meq/100g. Depending on whether the Cs adsorption occurred in the acidic and alkaline media at a temperature of 298.15 K in acidic media ?G0 values was -12.674 kJ/mol, while in alkaline media ?G0 was - 13.142 kJ/mol and a change of ?S0 to 42.51 J/molK in acidic media and 44.08 J/molK in alkaline medium.

Association of benflurone in aqueous solutions studied by measuring the activity of chloride ions

1986 ◽  
Vol 51 (11) ◽  
pp. 2437-2443
Author(s):  
František Kopecký ◽  
Mária Vojteková ◽  
Milan Pešák
Keyword(s):  
Aqueous Solutions ◽  
Chloride Ions ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Measured Range

The conventional activity of chloride ions was measured by an ion-selective electrode at 25 °C in aqueous solutions of benflurone, i.e. 5-(2-(N,N-dimethylamino)ethoxy)-7-oxo-7H-benzo(c)fluorene hydrochloride, without or with additions of KCl. These results suggest a gradual association of benflurone; the formation of a hetero-associate, (BH+)2Cl-, followed by higher associates was evaluated in the measured range up to 0.1 mol l-1.

Mn-Mo-O Catalysts for Methanol Oxidation. I. Preparation and Characterization of the Catalysts

1992 ◽  
Vol 57 (12) ◽  
pp. 2529-2538 ◽  
Author(s):  
Krasimir Ivanov ◽  
Penka Litcheva ◽  
Dimitar Klissurski
Keyword(s):  
Methanol Oxidation ◽  
Solution Concentration ◽  
Alkaline Media ◽  
Acidic Media ◽  
Chemical Methods ◽  
X Ray ◽  
Ph Values ◽  
Precipitate Composition

Mn-Mo-O catalysts with a different Mo/Mn ratio have been prepared by precipitation. The precipitate composition as a function of solution concentration and pH was studied by X-ray, IR, thermal and chemical methods. Formation of manganese molybdates with MnMoO4.1.5H2O, Mn3Mo3O12.2.5H2O, and Mn3Mo4O15.4H2O composition has been supposed. It is concluded that pure MnMoO4 may be obtained in both acid and alkaline media, the pH values depending on the concentration of the initial solutions. The maximum Mo/Mn ratio in the precipitates is 1.33. The formation of pure Mn3Mo4O15.4H2O is possible in weakly acidic media. This process is favoured by increasing the concentration of initial solutions.

scholarly journals Superior FexN electrocatalyst derived from 1,1′-diacetylferrocene for oxygen reduction reaction in alkaline and acidic media

2020 ◽  
Vol 9 (1) ◽  
pp. 843-852
Author(s):  
Hunan Jiang ◽  
Jinyang Li ◽  
Mengni Liang ◽  
Hanpeng Deng ◽  
Zuowan Zhou
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Current Density ◽  
Active Sites ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Acidic Media ◽  
Onset Potential ◽  
Acidic And Alkaline Media ◽  
The Stability

AbstractAlthough Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report FexN@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH3/Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe3O4 at 600°C and transforms to Fe3N and Fe2N at 700°C and 800°C, respectively. The as-prepared FexN@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared FexN@RGO as durable and active ORR catalysts in acidic media.

Effects of pH and ionic strength on the cation exchange capacity of soils with variable charge

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
Author(s):  
GP Gillman
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Surface Soils ◽  
Ph Values ◽  
Variable Charge ◽  
Effects Of Ph ◽  
Variable Charge Soils

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.

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