Abstract:The equilibrium and kinetics of methyl isobutyl ketone (MIBK) extraction resin for adsorption and separation of zirconium and hafnium were studied under the different conditions of acidity, initial total concentrations of zirconium and hafnium and temperature. The equilibrium data of both zirconium and hafnium are found to follow the Freundlich adsorption isotherm, and the Freundlich isotherm constants (K_F) are 3.53 and 0.64 mg/g, respectively. The equilibrium data of zirconium also fit the Langmuir adsorption isotherm, and the saturation adsorption capacity (Q_max) and the Langmuir isotherm constant (K_L) are 75.93 mg/g and −0.012 7 L/g, respectively. The obtained kinetic data of both zirconium and hafnium are found to fit the HO pseudo-second-order kinetic model, and the rate constants of pseudo-second-order equation (k₂) are −0.019 and 0.41 g/(mg·min), respectively. Column tests show that the MIBK extraction resin could be used as efficient adsorbent material for separating hafnium from zirconium.

Key words: equilibrium; kinetics; adsorption; methyl isobutyl ketone; extraction resin; zirconium; hafnium; separation