Synthesis and characterization of low-cost carbon nanotubes by chemical vapor deposition for aluminum removal from aqueous solution

Abstract

This study investigates novel multi-walled carbon nanotubes (MWCNTs) grown on agricultural waste, using loaded iron nanoparticles as catalyst templates and acetylene as carbon source through chemical vapor deposition under specific conditions, to wit: 550°C reaction temperature, 47 min reaction time, and 1 gas ratio. The specifications of MWCNTs are analyzed and characterized with the use of field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, ther-mogravimetric analysis, Brunauer–Emmett–Teller surface area analysis, and zeta potential analysis. The results reveal that MWCNTs have high quality and unique morphologies. The removal and capacity of Al3+ are optimized through response surface methodology, whilst the adsorption kinetics results are well ascribed to the pseudo-second-order model, the isotherm data are effectively fitted using a Langmuir model. The maximum adsorption capacity is 393.52 mg/g. The results demon-strate that MWCNTs can be regarded as a new low-cost adsorbent in wastewater treatment for the removal of Al3+. © 2021 Elsevier B.V., All rights reserved.