Surface enriched ternary hybrid via interfacial polymerization as an effective adsorbent for dye removal

Abstract

Methylene blue (MB) is a carcinogenic pollutant that can negatively affect both human health and marine life. Developing effective adsorbents for MB removal is therefore crucial for ensuring safe human life and mitigating environmental issues. Herein, we present an interfacial polymerization to synthesize polydopamine assisted multi-walled carbon nanotubes stitched graphene oxide (PDA@MWNTs/GO) as an effective adsorbent for MB removal. Stitching the PDA layer interfacially onto MWNTs/GO effectively prevents disintegration, diminishes agglomeration/restacking issues, and maximizes adsorption sites. The inherent catecholamine functionality within the PDA layer significantly enhances hydrophilicity. These distinctive characteristics endowed the PDA@MWNTs/GO composite with exceptional adsorption capacity for the cationic MB. The effects of MB concentration, pH, and temperature on the dye solution were thoroughly investigated. The results of the adsorption isotherm and kinetics analysis revealed conformity with the Langmuir isotherm model and adherence to the pseudo-second-order kinetic model. Moreover, PDA@MWNTs/GO demonstrated removal efficiency, exceeding 90% after three consecutive cycles of reuse. The adsorption mechanism was driven by electrostatic attraction and π–π stacking. The superior adsorption performance, attributable to the diverse functionalities and high removal efficiency, demonstrates the potential of PDA@MWNTs/GO as an efficient adsorbent for MB and can also function for other cationic dye impurities.