2D Ti₃C₂ MXene AND TiO₂/Ti3C2 HETEROSTRUCTURE: SYNTHESIS, CHARACTERIZATION, AND APPLICATION IN WASTEWATER TREATMENT VIA METHYLENE BLUE ADSORPTION

Abstract

The escalating discharge of toxic, non-biodegradable dyes from industrial activities necessitates advanced remediation strategies. This study synthesizes two-dimensional Ti₃C₂Tₓ MXene via hydrothermal etching of Ti₃AlC₂ MAX phase using NaBF₄/HCl, followed by delamination, and constructs a TiO₂/Ti₃C₂ heterostructure through NaOH/H₂O₂ treatment to evaluate their methylene blue (MB) adsorption efficacy. Structural characterization reveals successful Al-layer removal in MXene, evidenced by XRD peak shifts from 9.5° to 6.39° and FESEM/TEM-confirmed multilayered nanosheets. The MXene exhibits a high specific surface area, mesoporosity, and negative zeta potential of -31.8 mV, enabling 99.42% MB removal within 90 minutes via electrostatic interactions. In contrast, the TiO₂/Ti₃C₂ heterostructure, despite a larger surface area and 3D safflower-like TiO₂ morphology, shows reduced adsorption of 66.4%, due to diminished surface charges (-16.9 mV). XPS confirms terminal - O/-OH/-Cl groups in MXene, while BET analysis underscores pore structure advantages for rapid dye uptake. The heterostructure’s inferior performance highlights MXene’s superior standalone efficacy. This work underscores hydrothermally synthesized Ti₃C₂Tₓ MXene as a potent, scalable adsorbent for water purification, with future potential in hybrid systems and compares its structural properties and dye adsorbing capacities with TiO₂/Ti₃C₂ heterostructure and explains why the hydrothermally synthesized pristine Ti₃C₂Tₓ MXene is better towards synthetic dye removal than the sophisticated nanohybrids and heterostructures.