• • SH-Ti3C2Tx achieved an adsorption capacity of 55.6 mg·g−1 for As(III) at pH 7, 2.8 times higher than pristine Ti3C2Tx (20 mg·g−1), enabling more efficient removal in high-load scenarios.
• • The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics, confirming monolayer chemisorption via As–S bond formation, which ensures strong binding and stability.
• • The SH-Ti3C2Tx@MS flow-through column achieved 99.5% removal of As(III) from both 100 μg·L−1 and 100 mg·L−1 solutions, consistently reducing concentrations below the WHO standard of 10 μg·L−1.
• • Regeneration with 1 mol·L−1 NaOH allowed five consecutive adsorption–desorption cycles while maintaining >80% removal efficiency, demonstrating operational reusability and cost-effectiveness.