Adsorption Kinetics at Silica Gel/Ionic Liquid Solution Interface

Molecules

Jolanta Flieger¹  Małgorzata Tatarczak-Michalewska²  Anna Groszek²  Eliza Blicharska²  Ryszard Kocjan² 

[1] Department of Analytical Chemistry, Faculty of Pharmacy with Division of Medical Analytics, Medical University of Lublin, 4a Chodźki St., Lublin PL-20093, Poland

关键词: ionic liquids;    silica gel;    sorption kinetics;    pseudo-second-order equation;   

DOI  :  10.3390/molecules201219833

来源: mdpi

【 摘 要 】

A series of imidazolium and pyridinium ionic liquids with different anions (Cl⁻, Br⁻, BF₄⁻, PF₆⁻) has been evaluated for their adsorption activity on silica gel. Quantification of the ionic liquids has been performed by the use of RP-HPLC with organic-aqueous eluents containing an acidic buffer and a chaotropic salt. Pseudo-second order kinetic models were applied to the experimental data in order to investigate the kinetics of the adsorption process. The experimental data showed good fitting with this model, confirmed by considerably high correlation coefficients. The adsorption kinetic parameters were determined and analyzed. The relative error between the calculated and experimental amount of ionic liquid adsorbed at equilibrium was within 7%. The effect of various factors such as initial ionic liquid concentration, temperature, kind of solvent, kind of ionic liquid anion and cation on adsorption efficiency were all examined in a lab-scale study. Consequently, silica gel showed better adsorptive characteristics for imidazolium-based ionic liquids with chaotropic anions from aqueous solutions in comparison to pyridinium ionic liquids. The adsorption was found to decrease with the addition of organic solvents (methanol, acetonitrile) but it was not sensitive to the change of temperature in the range of 5–40 °C.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.