Novel Zwitterionic Inorganic−Organic Hybrids: Kinetic and Equilibrium Model Studies on Pb2+Removal from Aqueous Solution

2011 ◽  
Vol 56 (5) ◽  
pp. 2119-2127 ◽  
Author(s):  
Junsheng Liu ◽  
Long Song ◽  
Guoquan Shao
Keyword(s):  
Aqueous Solution ◽  
Equilibrium Model ◽  
Model Studies

The Chemistry of Formation of Some Secondary Arsenate Minerals of Cu(II), Zn(II) and Pb(II)

1988 ◽  
Vol 52 (368) ◽  
pp. 679-690 ◽  
Author(s):  
M. Clara F. Magalhães ◽  
Julio D. Pedrosa de Jesus ◽  
Peter A. Williams
Keyword(s):  
Aqueous Solution ◽  
Equilibrium Model ◽  
Stability Field ◽  
Secondary Minerals ◽  
Free Energy Of Formation ◽  
Dissolved Species ◽  
Solution Studies ◽  
Solubility Products ◽  
Chemical Conditions ◽  
Energy Of Formation

AbstractSolution studies have been carried out on natural and synthetic arsenate minerals, which are often found in the oxide zones of base metal orebodies. Solubility products and free energy of formation data have been derived for the minerals olivenite, cornubite, clinoclase, adamite, legrandite, euchroite, duftite, conichalcite, austinite, bayldonite, and schultenite at 298.2 K (25 °C). The data have been used in turn to construct stability field diagrams illustrating the chemical conditions under which the various species may crystallize from aqueous solution. This equilibrium model is then compared with several natural occurrences of the arsenate suites and it is demonstrated that it can be used to explain a number of observed paragenetic sequences. Descriptions of solution conditions which describe the stabilities of the arsenate minerals with respect to more commonly found secondary minerals of Pb(II), Cu(II), and Zn(II) involve more complex calculations and estimates of the likely levels of various dissolved species, but it is shown how these may be taken into account in the development of a more complex equilibrium model.

Electron-Beam Treatment of Aromatic Hydrocarbons That Can Be Air-Stripped from Contaminated Groundwater. 1. Model Studies in Aqueous Solution

2003 ◽  
Vol 37 (2) ◽  
pp. 372-378 ◽  
Author(s):  
Gertraud Mark ◽  
Heinz-Peter Schuchmann ◽  
Man Nien Schuchmann ◽  
Lutz Prager ◽  
Clemens von Sonntag
Keyword(s):  
Aqueous Solution ◽  
Electron Beam ◽  
Aromatic Hydrocarbons ◽  
Contaminated Groundwater ◽  
Electron Beam Treatment ◽  
Model Studies

scholarly journals Aggregation of p-Nitrophenyl Alkanoates in Aqueous Solution. Limitations on Their Use as Substrates in Enzyme Model Studies

1973 ◽  
Vol 51 (21) ◽  
pp. 3494-3498 ◽  
Author(s):  
J. Peter Guthrie
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Critical Concentration ◽  
Solubility Limit ◽  
Modest Increase ◽  
Model Studies ◽  
Critical Concentrations ◽  
Low Concentrations ◽  
Enzyme Model ◽  
Hydrolysis Of

p-Nitrophenyl alkanoates are aggregated at extremely low concentrations in aqueous solution. Second-order rate constants for imidazole or hydroxide catalyzed hydrolysis are independent of ester concentration up to a critical concentration of ester, and then decrease with increasing ester concentration. The critical concentrations at 25 °C are: p-nitrophenyl hexanoate, 1 × 10−4 M; octanoate, 9.6 × 10−6 M; decanoate, 1.2 × 10−6 M. For the dodecanoate ester, the critical concentration was estimated as ca. 10−7 M. Addition of 10% methanol causes only a modest increase in the critical concentration. The critical concentration probably represents the solubility limit of the ester. The rate constants for the hydrolysis of the longer chain esters evaluated here are significantly larger than those in the literature, suggesting that the earlier work was done using conditions where the esters were aggregated.

Sign in / Sign up

Export Citation Format

Share Document