Magnetite nanoparticles decorated on multi-walled carbon nanotubes for removal of Cu<sup>2+</sup> from aqueous solution
Natcha Temnuch, A. Suwattanamala, Saowaluk Inpaeng, Karaked Tedsree
Abstract
Acid-functionalized multi-walled carbon nanotube (MWCNTs-COOH) was prepared by acid treatment followed by decoration with magnetite (Fe3O4) nanoparticles (Fe3O4/MWCNTs-COOH) by co-precipitation of Fe2+/Fe3+ in the colloidal suspension of MWCNTs-COOH. The adsorption capacity and separation efficiency of these two adsorbents were investigated for the removal of Cu2+ ions in aqueous solution as water treatment adsorbents. The effect of reaction conditions, such as contact time, initial concentration of Cu2+ ions, and adsorbent dosage, on the adsorption capacity of MWCNTs-COOH was investigated. It was found that contact time of 10 min, adsorbent dosage of 0.2 g/L and 15 mg/L as initial concentration of Cu2+ ions are ideal conditions for maximum adsorption capacity (10.45 mg/g). The adsorption capacity of synthesized Fe3O4/MWCNTs-COOH containing different weight percent of Fe3O4 (10, 25, 50 wt%) was explored for removal of Cu2+ ions from aqueous solution and the best results achieved with 25 wt% Fe3O4/MWCNTs-COOH, which exhibited optimum adsorption capacity of 9.50 mg/g and 97% separation efficiency. Further, Langmuir and Freundlich isotherm models were applied to validate experimental data obtained in this work for Cu2+ adsorption.