The effect of ionic interactions on the oxidation of metals in natural waters     

Frank J Millero 《Geochimica et cosmochimica acta》1985,49(2):547-553

The effect of ionic interactions of the major components of natural waters on the oxidation of Cu(I) and Fe(II) has been examined. The various ion pairs of these metals have been shown to have different rates of oxidation. For Fe(II), the chloride and sulfate ion pairs are not easily oxidized. The measured decrease in the rate constant at a fixed pH in chloride and sulfate solutions agrees very well with the values predicted. The effect of pH (6 to 8) on the oxidation of Fe(II) in water and seawater have been shown to follow the rate equation where k₁ and k₂ are the pseudo first order rate constants, β₁ and β₂ are the hydrolysis constants for Fe(OH)⁺ and Fe(OH)⁰. The value of α_FE is the fraction of free Fe²⁺. The value of k₁ (2.0 ±0.5 min^?1) in water and seawater are similar within experimental error. The value of k₂ (1.2 × 10⁵ min^?1) in seawater is 28% of its value in water in reasonable agreement with predictions using an ion pairing model.For the oxidation of Cu(I) a rate equation of the form was found where k₀ (14.1 sec^?1) and k₁ (3.9 sec^?1) are the pseudo first order rate constants for the oxidation of Cu⁺ and CuCl⁰, β₁ is the formation constant for CuCl⁰ and α_Cu is the fraction of free Cu⁺. Thus, unlike the results for Fe(II), Cu(I) chloride complexes have measurable rates of oxidation.  相似文献   

Particulate pollution monitoring in the Elefsis Gulf: The role of mineral magnetic studies     

Frank Oldfield  Michael Scoullos 《Marine pollution bulletin》1984,15(6):229-231

Measurements of ‘quadrature’ susceptibility (X_q) at low and high frequency on seabottom sediments of the Gulf of Elefsis supplement the results derived from the study of magnetic susceptibility (X) and saturation isothermal remanent magnetization (SIRM) (Scoullos et al., 1979) and make possible the distinction between the background soil erosional fraction and that of anthropogenic combustion origin. New devices speed up the on-site appraisal of the impact of discharges on marine sediment quality.  相似文献   

Thermal histories of the core and mantle     

Frank D. Stacey  David E. Loper 《Physics of the Earth and Planetary Interiors》1984,36(2):99-115

Recognition that the cooling of the core is accomplished by conduction of heat into a thermal boundary layer (D″) at the base of the mantle, partly decouples calculations of the thermal histories of the core and mantle. Both are controlled by the temperature-dependent rheology of the mantle, but in different ways. Thermal parameters of the Earth are more tightly constrained than hitherto by demanding that they satisfy both core and mantle histories. We require evolution from an early state, in which the temperatures of the top of the core and the base of the mantle were both very close to the mantle solidus, to the present state in which a temperature increment, estimated to be ～ 800 K, has developed across D″. The thermal history is not very dependent upon the assumption of Newtonian or non-Newtonian mantle rheology. The thermal boundary layer at the base of the mantle (i.e., D″) developed within the first few hundred million years and the temperature increment across it is still increasing slowly. In our preferred model the present temperature at the top of the core is 3800 K and the mantle temperature, extrapolated to the core boundary without the thermal boundary layer, is 3000 K. The mantle solidus is 3860 K. These temperatures could be varied within quite wide limits without seriously affecting our conclusions. Core gravitational energy release is found to have been remarkably constant at ～ 3 × 10¹¹ W. nearly 20% of the core heat flux, for the past 3 × 10⁹ y, although the total terrestrial heat flux has decreased by a factor of 2 or 3 in that time. This gravitational energy can power the “chemical” dynamo in spite of a core heat flux that is less than that required by conduction down an adiabatic gradient in the outer core; part of the gravitational energy is used to redistribute the excess heat back into the core, leaving 1.8 × 10¹¹ W to drive the dynamo. At no time was the dynamo thermally driven and the present radioactive heating in the core is negligibly small. The dynamo can persist indefinitely into the future; available power 10¹⁰ y from now is estimated to be 0.3 × 10¹¹ W if linear mantle rheology is assumed or more if mantle rheology is non-linear. The assumption that the gravitational constant decreases with time imposes an implausible rate of decrease in dynamo energy. With conventional thermodynamics it also requires radiogenic heating of the mantle considerably in excess of the likely content of radioactive elements.  相似文献   

Zum Leistungsvermögen makroporöser Adsorberpolymere bei der Elimination organischer Mikroverunreinigungen     

H.-J. Walther  J. Kaeding  P. Fechner 《洁净——土壤、空气、水》1984,12(2):173-181

In laboratory experiments the adsorption of eleven different organic substances in water is individually tested in the range of concentration of 0.2… 5.0 mg/l on EP 60 and EP 61 (styrene-divinylbenzene, non-polar) and EP 62 and Y 59 (acrylic-acid-ester-divinylbenzene, polar). In batch experiments the elimination at 1… 2 g/l adsorber quantity was 35… 80%, strongly dissociated anionic substances as benzoic acid being adsorbed only to a low degree and weakly cationic and undissociated substances being adsorbed well. Within a homologous series adsorption increases with the molar mass until the pore diameter will become too small for the taking up of substances. Under dynamic conditions (filtration technology) an elimination of 90… 100% can be expected. As a whole, the adsorption on activated carbon was better in all cases than the adsorption on the polymers. The desorption for the regeneration of the polymers is the more difficult the better the substance contained is adsorbed. By repeated loading and regeneration only a slight influence on the adsorption and desorption of a substance was found.  相似文献   

Use of Pitzer's equations to determine the media effect on the formation of lead chloro complexes     

Frank.J. Millero  Robert H. Byrne 《Geochimica et cosmochimica acta》1984,48(5):1145-1150

The spectrophotometric measurements of chloro complexes of lead in aqueous HCl, NaCl, MgCl₂ and CaCl₂ solutions at 25°C have been analyzed using Pitzer's specific interaction equations. Parameters for activity coefficients of the complexes PbCl⁺, PbCl₂⁰ and PbCl₃^? have been determined for the various media. Values of $\text{K}{}_1\text{= 30.0 ± 0.6}$, $\text{K}{}_2\text{= 106.7 ± 2.1}$ and $\text{K}{}_3\text{= 73.0 ± 1.5}$ were obtained for the cumulative formation constants. [$\text{Pb}{}^{\mathrm{2+}}\text{+ nCl}{}^{\mathrm{?}}\text{→ PbCl}{}_{\mathrm{n}}{}^{\mathrm{2?n}}\text{)}$]. These values are in reasonable agreement with literature data. The Pitzer parameters for the PbCl ion pairs in various media were used to calculate the speciation of Pb²⁺ in an artificial seawater solution.  相似文献   

Description and interpretation of the composition of fluid and alteration mineralogy in the geothermal system,at Svartsengi,Iceland     

Kristín Vala Ragnarsdóttir  John V Walther  Stefán Arnórsson 《Geochimica et cosmochimica acta》1984,48(7):1535-1553

The bulk composition and mineralogy of hydrothermally altered tholeiite, along with the composition and speciation of fluid, have been determined for a well-defined alteration zone at 240°C and 110 bars at Svartsengi, Iceland. Mass balances between the geothermal fluid and altered tholeiite, relative to a seawater/fresh water mixture and unaltered tholeiite, indicate the overall reaction per 1000 cm³ is: 1325 gm plagioclase + 1228 gm pyroxene + 215 gm oxide-minerals break down to form 685 gm chlorite + 636 gm albite + 441 gm quartz + 249 gm epidote + 266 gm calcite + 201 gm oxide-minerals + 15 gm pyrite, requiring an influx of 123 gm CO₂, 10 gm H₂S and 4 gm Na₂O and a release of 57 gm SiO₂, 35 gm FeO, 21 gm CaO, 8 gm MgO and 4 gm K₂O.Principal reactions, deduced from textural evidence, include Na-Ca exchange in plagioclase, precipitation of quartz, calcite and anhydrite, and formation of chlorite and epidote by reactions between groundmass minerals and fluid.Thermodynamic analyses of authigenic minerals and downhole fluid indicate that the fluid maintains a state close to equilibrium with the secondary mineral phases chlorite, epidote, albite, quartz, calcite, prehnite, anhydrite, pyrite and magnetite, whereas remnant primary labradorite and augite are out of equilibrium with the fluid.Water/rock ratios for the system are determined under a variety of assumptions. However, the open nature of the system makes comparisons with experimental and theoretical closed system studies ambiguous.  相似文献   

Lehr- und Handbuch der Abwassertechnik. 3. Aufl., Bd. IV: Biologisch-chemische und weitergehende Abwasserreinigung. Hrsgb. v. d. ABWASSERTECHNISCHEN VEREINIGUNG e. V. in St. Augustin,Berlin, Ernst & Sohn, 1985, 877 S., 458 Abb., 91 Tab., DM 278,–; ISBN 3-433-00905-8     

H.-J. Walther 《洁净——土壤、空气、水》1987,15(2):124-124

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Lehr- und Handbuch der Abwassertechnik. 3. Aufl., Bd. V: Organisch verschmutzte Abwässer der Lebensmittelindustrie. Hrsgb. v. d. ABWASSERTECHNISCHEN VEREINIGUNG e. V. in St. Augustin,Berlin, Ernst & Sohn, 1985, 660 S., 178 Abb., 229 Tab., DM 198,–, ISBN 3-433-00906-6     

H.-J. Walther 《洁净——土壤、空气、水》1987,15(2):148-148

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Festschrift zur Emeritierung von Professor Dr.-Ing., Dr. h. c. Botho Böhnke am 31. März 1987. Gewässerschutz – Wasser – Abwasser 95, Aachen 1987, 506 S., 124 Abb., 48 Tab., DM 45,–, ISSN 0342-2-6068     

H.-J. Walther 《洁净——土壤、空气、水》1987,15(6):687-687

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Zur Aufbereitung von Oberflächenwässern unter Einsatz von Kalkhydrat     

H.-J. Walther 《洁净——土壤、空气、水》1982,10(6):623-630

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