Fabrication of three-dimensional MXene-MWCNT composite for the swift removal of cationic BB3 Dye from aqueous solution

Abstract

The contamination of aquatic ecosystems with synthetic dyes is a considerable environmental concern due to their detrimental properties and persistence. Basic blue 3 (BB3), an aromatic dye, poses significant hazards owing to its cancer-causing properties, hence requiring efficient removal techniques. Investigating versatile materials that effectively remove contaminants from wastewater is of paramount significance for ecological restoration. This study developed an MXene-Multi-walled carbon nanotube (MXene-MWCNT) composite adsorbent for the removal of BB3 dye from aqueous solutions. Multi-layered MXene was produced via the etching of the Ti 3 SiC 2 MAX phase employing HF–H 2 O 2 , followed by the preparation of the MXene-MWCNT composite via a solvothermal approach. The synthesized composite was analyzed by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Brunauer–Emmett–Teller (BET), Raman, and infrared (IR) spectroscopic techniques, suggesting the effective incorporation of MWCNT with MXene nanosheets. BET studies revealed that MXene-MWCNT maintained a mesoporous structure (39.46 Å) with a specific surface area (SSA) of 15.37 m 2 g − 1 . The adsorbent exhibited swift and effective BB3 elimination, attaining 99% removal within 27 min and showcasing an adsorption capacity of 217 mg g − 1 . Adsorption kinetics adhered to a pseudo-second-order model. Adsorption isotherm analysis demonstrated a strong correlation with the Langmuir model (R 2  = 0.9996), implying the occurrence of monolayer adsorption. Thermodynamic analysis indicates that the adsorption process is spontaneous and endothermic in nature. Electrostatic attraction, hydrogen bonding, and π–π stacking govern the mechanisms of adsorption between BB3 molecules and the functional groups of MXene-MWCNT. The composite demonstrated a removal efficacy over 90% after five rejuvenation cycles, affirming its notable reusability. These findings indicate that the MXene-MWCNT nanocomposite shows potential for BB3 removal from aqueous solutions.