The Influence of Oxygen on the Adsorption of Metal Cyanides on Activated Carbon

Merwe, P. F. Van Der; Deventer, J.S.J. van

doi:10.1080/00986448808940248

Cited by 29 publications

(6 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Though direct comparison to gold isotherms found in literature is difficult due to the many factors, that affect the adsorption of metal cyanide complexes, for example the activity 1 of the activated carbon used, the adsorption equipment and stream constituents like oxygen, electrolytes, pH and cyanide (Fleming and Nicol, 1984;Van der Merwe and Van Deventer, 1988;Woollacott and Nino de Guzman, 1993), the Pt and Pd isotherms in this case were plotted against gold isotherms obtained from literature to serve as a reference for Pt and Pd. The gold isotherm ( Fig.…”

Section: Equilibrium Isothermsmentioning

confidence: 99%

The effect of temperature, cyanide and base metals on the adsorption of Pt, Pd and Au onto activated carbon

et al. 2014

View full text Add to dashboard Cite

Section: Equilibrium Isothermsmentioning

confidence: 99%

The effect of temperature, cyanide and base metals on the adsorption of Pt, Pd and Au onto activated carbon

et al. 2014

View full text Add to dashboard Cite

“…The adsorption of complex gold cyanides is an important industrial application of active carbon adsorbents and has been extensively investigated all over the world. − There is still no agreement on the exact mechanism of the selective adsorption of gold complexes onto activated carbons from aqueous solution. A number of adsorption mechanisms of gold from potassium aurocyanide solutions onto activated carbons have been proposed over the years. − The most recent theories 12,13,15,17-19,21,24,26,27 favor the adsorption of gold as Au(CN) 2 - without chemical change. There is much controversy about the nature of the adsorption sites in carbon adsorbents.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study on the Adsorption of Cyanide Gold Complexes onto Different Carbonaceous Samples: Measurement of the Reversibility of the Process and Assessment of the Active Surface Inferred by Flow Microcalorimetry

et al. 1999

View full text Add to dashboard Cite

In this paper, adsorption of potassium gold cyanide from water onto three activated carbon samples, four graphites, and two carbon blacks (Graphon and Vulcan) is compared. The present work collects the results of flow microcalorimetric studies for each carbonaceous adsorbent so as to obtain estimates of their polar and accessible apolar graphitic basal plane surface areas. The relative polar and graphitic nature of the carbons is evaluated and related where possible to their capacity of adsorption for gold complexes. Finally, the thermodynamic reversibility of gold adsorption on the carbonaceous adsorbents from an aqueous solution of potassium aurocyanide at room temperature has also been studied. A flow adsorption microcalorimetry method was used to measure the amounts of aurocyanide adsorbed and desorbed in one adsorption−desorption cycle, as well as the corresponding enthalpic changes upon adsorption and desorption. On the basis of the adsorption and enthalpy values obtained in adsorption and desorption cycles, estimates could be made of the reversible and irreversible contributions to the total adsorption capacity and the integral molar enthalpy of adsorption. The degree of adsorption irreversibility ranges from 25% for Graphon to 54% for G212. The irreversible and reversible enthalpy components have respective values of about −50 and −25 kJ mol-1. A large part of the microporous structure in activated carbons is not accessible to the adsorption of gold complexes. One part of the aurocyanide is believed to irreversibly adsorb as an unpaired anion Au(CN)2 - through electrostatic interactions on the very active surface sites having polar character. The less active sites are occupied by the ion-paired neutral molecular species (KAu(CN)2) through the action of van der Waals forces and account for the reversible adsorption. In reversible and irreversible processes, the active sites are thus expected to be associated with the graphitic-like structure containing nonideal aromatic rings and polar structures located at the edge defects in the graphite structure.

show abstract

“…The same mechanisms can be utilized to adsorb contaminants from a water column. At the present time only experimental studies have been carried out (Hegenberger et al 1987;McEnamey 1988;van der Merwe & van Deventer 1988). The technique has also been applied to volatile and dense organic solvents (Pankow & Cherry 1996).…”

Section: Ph = Hydraulic Pressure Po = Osmotic Pressurementioning

confidence: 99%

Chemical containment of mine waste

Bowell¹,

Williams²,

Connelly³

et al. 1999

View full text Add to dashboard Cite

The safe disposal of material considered hazardous is a natural part of good housekeeping for any industrial development. This is particularly so for the mining industry which has historically not always been so well managed in this aspect and as such has a high political profile today. Typical problems associated with mineral processing and mine waste are:9 poor water quality, through the release of sulphate, acidic waters, metals, metalloids and other undesirable substances 9 poor air quality, through the release of mineral dust and gases such as SO2, As203, Hg vapour and CO2 amongst others 9 contamination of land by the above with elevated levels of metals, sulphate and metalloids.

show abstract

The Influence of Oxygen on the Adsorption of Metal Cyanides on Activated Carbon

Cited by 29 publications

References 2 publications

The effect of temperature, cyanide and base metals on the adsorption of Pt, Pd and Au onto activated carbon

The effect of temperature, cyanide and base metals on the adsorption of Pt, Pd and Au onto activated carbon

Comparative Study on the Adsorption of Cyanide Gold Complexes onto Different Carbonaceous Samples: Measurement of the Reversibility of the Process and Assessment of the Active Surface Inferred by Flow Microcalorimetry

Chemical containment of mine waste

Contact Info

Product

Resources

About