Assembling polypyrrole coated sepiolite fiber as efficient particle adsorbent for chromium (VI) removal with the feature of convenient recycling

Abstract

To overcome the inherent defect of particle adsorbent that difficult to be recycled from waterbody, a new adsorbent was successfully prepared based on the surface polypyrrole (PPy) functionalized sepiolite fiber (SEP), with properties of magnetism and floatation. This adsorbent can be recovered easily from water surface by a magnet. The resultant MSEP/PPy retains the feature of sepiolite fiber template, along with a large surface area to have more surface adsorption sites. Batch experiment shows the experiment data is in good agreement with the pseudo-second order kinetic and Langmuir isotherm model. The adsorption mechanism reveals that the ion exchange occurs between Cl− and Cr(VI), followed by the reduction of Cr(VI) to Cr(III) via the surface PPy moiety. Additionally, most of the adsorption capacity of the adsorbent can be maintained in the cyclic regeneration, ranging from 87.93 to 58.36 mg/g even in the incomplete desorption.