Extraction of Copper in ZSM-5 with a RTIL

Abstract

Speciation of copper extracted with a RTIL (room temperature ionic liquid) ([C₄mim][PF₆], 1-butyl-3-methylimidazolium hexafluorophosphate) has been studied by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopy in the present work. The extraction of copper in the channels of ZSM-5 with the RTIL turns out to be very effective. The least-square fitted XANES spectra show that the main copper species (Cu²⁺_(ads) (99%)) in the channels of ZSM-5 can be extracted with the RTIL and form the Cu(mim)₄²⁺ complex. The bond distance of Cu-N in the Cu(mim)₄²⁺ is 1.96 Å with a coordination number of 3.6.