Recovery Process for Critical Metals: Selective Adsorption of Nickel(II) from Cobalt(II) at Acidic Condition and Elevated Temperature

Table 5

Correlation between proton release per adsorbed metal ion during adsorption, stability constant , and molar equilibrium loading at °C in different competitive adsorption experiments at Ni(II) : Co(II) molar ratio of 1 : 1.

Adsorptives	(μmol·L^-1)	Metal ion : ligand ratio; (μmol(M(II)) · μmol(Ligand)^-1)	pHeq	Released H^+ : adsorbed metal ion ratio; (μmol(H^+) · μmol(M(II))^-1)		(μmol(M(II))·μmol(Ligand)^-1)
Ni(II) and	1000	0.4 : 1	2.3	3.0	4.36	0.17
Co(II)	1000				2.84	0.13
Ni(II) and	2800	1 : 1	2.2	2.2	3.32	0.45
Co(II)	2800				1.68	0.06
Ni(II) and	5600	2 : 1	2.1	2.4	2.69	0.54
Co(II)	5600				1.52	0.07
Ni(II) and	15000	6 : 1	2.0	1.8	2.76	0.85
Co(II)	15000				1.47	0.09