Degradation of 2,4-dichlorophenol using palygorskite-supported bimetallic Fe/Ni nanocomposite as a heterogeneous catalyst

Abstract

Abstract A functional palygorskite-supported Fe/Ni (Pal-Fe/Ni) nanocomposite material is synthesised to remove 2,4-dichlorophenol (2,4-DCP) in an aqueous solution. The hypothesis is that Pal-Fe/Ni has superior efficacy than other Fe materials, such as Pal-Fe and Fe/Ni with regard to 2,4-DCP removal even though it requires less loading amount of metallic influencing the reaction. The surface morphology and surface chemical environments of Pal-Fe/Ni are studied using SEM, TEM, XRD and XPS characterisation methods. As revealed from batch experiments, initial pH, sample amount and reaction time are the key parameters influencing the 2,4-DCP removal efficiency. A further experiment reveals that iron leaching plays a main role for 2,4-DCP removal. Kinetic study reveals that removal of 2,4-DCP can be described by pseudo first-order model. A synergistic adsorption and catalytic reduction mechanism for the removal of 2,4-DCP by Pal-Fe/Ni is studied using UV–Vis, total organic carbon and HPLC-MS analyses. The results reveal complete dechlorination and 2,4-DCP degradation together with high total organic carbon removal. This study on immobilising Fe/Ni bimetallic nanoparticles onto palygorskite creates a new prospect for the practical application of Pal-Fe/Ni nanocomposite in remediation of contaminated aqueous solutions.