Adsorption Behavior of Quaternary Amine Types of Lignophenol Compounds for Some Precious Metals

Two kinds of quaternary amine type lignophenol derivatives were prepared and tested for the adsorption behavior of Au(III), Pd(II), Pt(IV), Cu(II), Fe(III), and Zn(II) in hydrochloric acid medium. Both the derivatives were found to exhibit excellent selectivity for precious metals with negligible adsorption for other metal ions. The adsorption isotherm study established the Langmuir type adsorption model, and from the respective adsorption isotherms, the maximum loading capacities for Au(III), Pd(II), and Pt(IV) were evaluated. Ionic interaction between the positive moiety of quaternary amine functional groups and the anionic chloride complexes formed by the precious metal ions in acidic chloride media was concluded as the main adsorption mechanism.