Surface Modification of MWCNTs with Carboxylic-to-Amine and Their Superb Adsorption Performance

Abstract

In this study, multi-walled carbon nanotubes (MWCNT) surface functionalization with amine group is studied for methyl orange (MO) dye removal from aqueous solution. The adsorbent was prepared using 1,2-ethylenediamine as amine via a microwave combination to functionalize the carbon nanotubes with carboxylic acid (–COOH) then converting to acyl chloride (–COCl) as intermediate using thionyl chloride. The prepared material shows a suburb adsorption performance of MO removal with a high adsorption capacity of 96 mg g−1. In addition, the equilibrium data are introduced by the Langmuir and Freundlich isotherms, and showed Langmuir is the best fit with the adsorption capacity of 25.73 mg g−1. Moreover, pseudo-second order is found to be the best kinetic model to fit the experimental data. According to kinetics results, the adsorption process involves chemisorption step. MWCNT–NH2 is an excellent candidate to be used as an effective adsorbent for pollution removal from the aqueous environment.