Photodissolution of iron oxides in malonic acid

1994 ◽  
Vol 72 (10) ◽  
pp. 2037-2043 ◽  
Author(s):  
Marta I. Litter ◽  
Marina Villegas ◽  
Miguel A. Blesa
Keyword(s):  
Ascorbic Acid ◽  
Aqueous Solutions ◽  
Iron Oxides ◽  
Malonic Acid ◽  
Numerical Solutions ◽  
Kinetic Equations ◽  
Dark Reaction ◽  
Thermal Dissolution ◽  
Photochemical Initiation ◽  
Fitting Parameters

The influence of 254-nm irradiation on the dissolution rate of magnetite (Fe3O4) and maghemite (γ-Fe2O3) suspended in aqueous solutions of malonic acid is analyzed and compared with the dark reaction. The effect of the addition of Fe3+, reductants such as ascorbic acid and oxidants such as Ag+ or O2 is described. Photochemical initiation involves the production of >FeII by electrons photogenerated on the oxide, which triggers thermal dissolution. Experimental results are fitted by analytical and numerical solutions of the set of kinetic equations. The calculated fitting parameters reflect the lower activity of iron oxides in malonic acid compared to EDTA media.

scholarly journals Adsorption Study for Trifluralin on Iraqi ? –Alumina

2012 ◽  
Vol 9 (1) ◽  
pp. 153-159 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Adsorption Isotherm ◽  
Aqueous Solutions ◽  
Contact Time ◽  
Adsorption Process ◽  
Kinetic Equations ◽  
Adsorption Study ◽  
Adsorption Capacities ◽  
Experimental Parameters ◽  
Freundlich Adsorption Isotherm ◽  
Equilibrium Adsorption Isotherm

Equilibrium adsorption isotherm for the removal of trifluralin from aqueous solutions using ? –alumina clay has been studied. The result shows that the isotherms were S3 according Giels classification. The effects of various experimental parameters such as contact time, adsorbent dosage, effect of pH and temperature of trifluralin on the adsorption capacities have been investigated. The adsorption isotherms were obtained by obeying freundlich adsorption isotherm with (R2 = 0.91249-0.8149). The thermodynamic parameters have been calculated by using the adsorption process at five different temperature, the values of ?H, ?G and ?S were (_1.0625) kj. mol-1, (7.628 - 7.831) kj.mol-1 and (_2.7966 - _2.9162) kg. k-1. mol-1 respectively. The kinetic study of adsorption process has been studied depending on three kinetic equations: 1- Allergen equation 2- Morris –weber eguation 3- Reichenberg eguation. In general, the result shows the isotherm were on ?- alumina according to Giels classification.? –alumina and thermodynamic

scholarly journals Rubeanic Add as Stabilizer of Aqueous Solutions of Ascorbic Acid

Nature ◽  
1961 ◽  
Vol 192 (4798) ◽  
pp. 161-161 ◽  
Author(s):  
ALEKSANDRA SMOCZKIEWICZOWA ◽  
JANINA GROCHMALICKA
Keyword(s):  
Ascorbic Acid ◽  
Aqueous Solutions

Mixed iron oxides as Fenton catalysts for gallic acid removal from aqueous solutions

2016 ◽  
Vol 196 ◽  
pp. 207-215 ◽  
Author(s):  
María A. Fontecha-Cámara ◽  
Carlos Moreno-Castilla ◽  
María Victoria López-Ramón ◽  
Miguel A. Álvarez
Keyword(s):  
Aqueous Solutions ◽  
Gallic Acid ◽  
Iron Oxides

Conditions of formation of the iron-containing minerals, Hällefors silver mines, Bergslagen, Sweden

1986 ◽  
Vol 50 (355) ◽  
pp. 101-110 ◽  
Author(s):  
A. W. Jasiński
Keyword(s):  
Aqueous Solutions ◽  
Iron Oxides ◽  
Iron Ore ◽  
Silver Deposit ◽  
Ore Deposit ◽  
Iron Minerals ◽  
Sulphide Precipitation ◽  
Iron Ore Deposit ◽  
Two Stages

AbstractThe Hällefors silver deposit is regarded as a volcanogenic-exhalative iron ore deposit with dispersed amounts of Ag-Pb-Zn (±Cu) which has undergone secondary remobilization leading to the concentration of sulphides and sulphosalts. Based on data from the iron oxides and sulphides, the sulphide-sulphosalt mineralization is believed to have been formed in two stages. The first is characterized by the ranges 573-473 K and 2.25–1.5 kbar, higher gradient of changes of log aS2 with temperature and mostly sulphide precipitation; the second by the ranges 473–443 K, lower gradient of changes of log aS2 and mainly sulphosalt deposition. Assuming the precipitation was from fluids and aqueous solutions, possible conditions of formation of some of the iron minerals have been determined.

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