Novel bio-based Pd/chitosan-perlite composite bead as an efficient catalyst for rapid decolorization of azo dye

Abstract

Perlite that is a volcanic glass was applied along with chitosan to form chitosan-perlite beads through a facile procedure. The as-prepared beads were then cross-linked with glutaraldehyde and utilized as a bio-based supporting material for the immobilization of Pd nanoparticles via wet impregnation method. The resultant catalyst was characterized via XRD, SEM, TEM, ICP, TGA, FTIR and elemental mapping analysis and its performance was then appraised for decolorization of Methyl orange dye in aqueous media at ambient temperature in the presence of sodium borohydride as a reducing agent. The results established that scant amount of the catalyst, 1.5 mg, could promote the reaction in 2 min to decolorize the dye with yield = 100 %. Using the experimental data, activation energy, enthalpy, and entropy of the decolorization reaction were calculated to be 35.98 kJ/mol, 33.44 kJ/mol, −166.22 J/mol.K, respectively. The catalyst was recyclable up to eight runs with insignificant loss of catalytic activity and Pd leaching.