Sulfhydryl functionalized two-dimensional Ti₃C₂T_x MXene for efficient removal of Hg²⁺ in water samples

This study describes an adsorption method for the removal of Hg²⁺ from aquatic environments using sulfhydryl-functionalized Ti₃C₂T_x (SH-Ti₃C₂T_x). SH-Ti₃C₂T_x materials were synthesized through covalent interactions between dithiothreitol and two-dimensional Ti₃C₂T_x. The insertion of -SH groups increased the interlayer spacing of Ti₃C₂T_x, resulting in a 3-fold increase in the specific surface area of SH-Ti₃C₂T_x compared with the original Ti₃C₂T_x. The maximum Hg²⁺ adsorption capacity of SH-Ti₃C₂T_x was 3042 mg/g, which was 2.3-fold greater than that of Ti₃C₂T_x. After Hg²⁺ adsorption, SH-Ti₃C₂T_x was regenerated for repeated used by rinsing with HCl-thiourea. Next, SH-Ti₃C₂T_x was loaded onto a melamine sponge to construct SH-Ti₃C₂T_x adsorption columns suitable for continuous flow Hg²⁺ removal with extremely low flow resistance. Hg²⁺ removal rates exceeded 95 % when treating both high and low-concentration solutions (20 mg/L Hg²⁺ and 10 μg/L Hg²⁺). This study demonstrates the excellent adsorption-regeneration performance of SH-Ti₃C₂T_x, which has broad application prospects for the in-situ treatment of water contaminated with Hg²⁺.