Copper ions removal from water using functionalized carbon nanotubes–mullite composite as adsorbent

•CNTs–mullite composite was prepared via chemical vapor deposition (CVD) method.•The prepared composite was modified with concentrated nitric acid and chitosan.•The modified CNTs–mullite composites were used as novel adsorbents.•Copper ion removal from water by the prepared adsorbents was performed.•Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data.

Carbon nanotubes–mullite composite was synthesized by direct growth of carbon nanotubes on mullite particles via chemical vapor deposition method using cyclohexanol and ferrocene as carbon precursor and catalyst, respectively. The carbon nanotubes–mullite composite was oxidized with concentrated nitric acid and functionalized with chitosan and then used as a novel adsorbent for copper ions removal from water. The results demonstrated that modification with concentrated nitric acid and chitosan improves copper ions adsorption capacity of the prepared composite, significantly. Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. The carbon nanotubes growth on mullite particles to form the carbon nanotubes–mullite composite with further modification is an inherently safe approach for many promising environmental applications to avoid some concerns regarding environment, health and safety. It was found that the modified carbon nanotubes–mullite composite can be considered as an excellent adsorbent for copper ions removal from water.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide