Efficient Adsorption of Cu(II) Ions by a Laminar Nanocomposite of Multi-Walled Carbon Nanotubes Coupled with Fungal Mycelium in Aqueous Solution

Abstract

Nowadays, extensive use of copper in electric industries has severely contaminated aquatic environments. To address this issue, combining fungal biomass with nanomaterials is considered as an efficient way for adsorbing heavy metals from wastewater. In this work, a novel composite material "Fungal mycelium coupled with Carbon nanotubes" (FM-CNTs) was synthesized and used for adsorption of Cu(II) ions in aqueous solution. To begin with, potassium permanganate and concentrated nitric acid were used as strong oxidants to modify the surface of CNTs, creating additional carboxyl groups for coupling with amine groups from the surface of FM. Next, various characterization approaches such as SEM-EDX, FT-IR, XPS and TGA, were used to investigate the interaction between FM-CNTs and Cu(II) ions. Characterization results showed that the surface of FM-CNTs were significantly changed after absorbing Cu(II) ions. Further, the effect of pH on adsorption capacity of FM-CNTs for Cu(II) was explored, showing that FM-CNTs had the best adsorption performance at pH of 5. Finally, Langmuir-Freundlich isothermal models were performed to analyze the adsorption behavior of FM-CNTs for Cu(II). The experimental data from the adsorption of Cu(II) by FM-CNTs were best fitted to the Langmuir model, and the maximum adsorption amount of the FMCNTs for Cu(II) was found to be 342.22 mg/g. More importantly, FM-CNTs showed better adsorption capacity than fungal mycelium alone. Overall, FM-CNTs exhibited excellent performance for adsorption of Cu(II) ions, thus greatly broadening its application prospects in copper-contaminated wastewater treatment.