Fenton-based processes for the regeneration of catalytic adsorbents

Abstract

In the present study, natural phyllosilicate clays, Illite and Montmorillonite, were stablished as efficient adsorbents for the removal of the ionic liquid 1-butyl, 2,3-dimethyl imidazolium chloride, achieving, respectively, 14 and 25mg/g of adsorption. In addition, the regeneration of both adsorbents was hereby firstly performed by Fenton-based processes, using the catalytic action of the iron naturally present in clays. Two different reactor configurations, with regard to the ratio of adsorbent to liquid phase, were tested: fluidized and fixed bed reactors. The desorption equilibrium was the main limiting factor for the effective regeneration of the Illite clay by electro-Fenton process in the fluidized bed reactor. On the other hand, the fixed bed reactor, based on electrokinetic-Fenton phenomenon, proved to be suitable for the regeneration of the Montmorillonite clay and it would be an appropriate solution for the implementation of adsorbent regeneration by Fenton-based technology at large adsorbent/solution ratios. Both reactor configurations were suitable for the adsorbents regeneration, and 80% of ionic liquid degradation has been accomplished. Additionally, the adsorption capability of both clays was confirmed after the regeneration process, achieving almost the same initial uptake.