MXene-based 2D Ti3C2Tx nanosheets for highly efficient cadmium (Cd2+) adsorption

In aqueous streams, pollutants such as heavy metals, textile dyes, medicines, salts, and aromatic chemicals pose a threat to the environment. In the present study, Ti3C2Tx (MXene) was synthesized from Ti3AlC2 (MAX phase) using hydrofluoric acid (HF) etching and its morphology and functionalities were investigated. The performance of the synthesized MXene as an adsorbent was evaluated to remove cadmium (Cd2+) from an aqueous solution. The effects of operating parameters, including contact time, temperature, pH, adsorbent dose, and initial pollutant concentration were studied to determine optimized conditions for Cd2+ adsorption. The adsorption capacity of MXene for 100 mg·L−1 of Cd2+ was 475.6 mg·g−1. Thermodynamic models analysis showed that the adsorption of Cd2+ was a spontaneous and exothermic process. The Langmuir isotherm (R2 = 0.981), and pseudo-second-order kinetic (R2 = 0.999) were found to better describe a homogenous monolayer sorption dominated by surface complexation. This study provides valuable insights into the adsorption characteristics of 2-D MXene sheets for the removal of Cd2+ from wastewater.