Fe3S4 intercalated alkalized MXenes to enhancement of Au(III) and Cr(VI) removal by reduction and immobilization synergistic effect

Abstract

Herein, Fe3S4 particles were introduced into an alkalized-Nb2CTx MXenes to construct Fe3S4@Alk-Nb2CTx composite for simultaneous reduction-immobilization of Au(III)/Cr(VI) from water aqueous. Spectrum analysis revealed that the –OH groups on the Alk-Nb2CTx surface assisted improving the dispersion and stability of Fe3S4, resulting in a favorable morphology and structure. The synthesized composites exhibited superior adsorptive property with a maximum adsorption values for Au(III) (2544.3 mg/g) and Cr(VI) (204.8 mg/g). Meanwhile, the removal of targeted pollutants on Fe3S4@Alk-Nb2CTx followed Pseudo-second order kinetics model and showed a good fit with the Langmuir isotherm model, indicating the nature of monolayer chemisorption. Besides, high adsorption selectivity of Fe3S4@Alk-Nb2CTx was still observed in the presence of interference ions, and it could be separated conveniently from solution by a magnet. More importantly, the model-fitting and characterization results manifested that high-density Fe, S and O groups were the main active factors in the as-prepared adsorbents, while the electrostatic attraction, complexation, redox and precipitation dominated the adsorption process. Hence, Fe3S4@Alk-Nb2CTx was a promising candidate employed for in situ environmental pollution incidents, especially competent for the reduction and removal of Au(III)/Cr(VI).