Adsorption of [Au(CN)2]− ions from aqueous solutions on an activated carbon surface

Evaluation of gold adsorption on activated carbon from real cyanide and thiourea leachate solutions

“…The equilibrium data were fitted to Freundlich's isothermal model [ 17 , 41 ]. Taking into account the literature [ 3 , 35 , 42 , 43 ], the amount of metal adsorbed (equilibrium adsorption capacity) by the activated carbon, q e (mg/g), was evaluated using equation (7) ; where C o and C e (mg/L) are the initial and equilibrium concentration of ions in solution, respectively, V (L) is the solution volume, and m (g) the weight of activated carbon.…”

“…The process of gold adsorption on activated carbon active sites was described by Ibraginova et al [ 17 ], in a series of stage: i) transfer of [Au(CN) 2 ] - ions from within the solution to the boundary layer surrounding the activated carbon particle; ii) transfer of the [Au(CN) 2 ] - anion and a cation into the adsorbent particle, from the pore mouth; iii) adsorption of gold-containing particles onto the active sites of the adsorbent and, iv) transfer of the adsorbed gold complex ion particles along the pore walls into the active sites of the activated carbon (surface diffusion). The initial rate of adsorption of the gold di-cyanide complex is fast and controlled by mass transport in the liquid film surrounding the activated carbon particles [ 5 , 18 ].…”