Ti3C2Tx MXene playing as a strong methylene blue adsorbent in wastewater

Abstract

Layer-structured MXenes recently attract a great deal of interest due to their intriguing properties. Despite the broad and intensive research, some of their application areas have been scarcely highlighted. In this work, it was demonstrated that the mostly F-terminated Ti3C2Tx MXene could play as a strong adsorbent of methylene blue (MB) in wastewater. For this, the MXene was synthesized by Al-selective etching of Ti3AlC2 MAX phase using HF. At a standard condition, the MXene turned out to be terminated mostly with F functional groups. Remarkably, the mostly F-terminated MXene adsorbed approximately 92% of MB in 20 M of MB aqueous solution within 5 min. It was found that the surface termination groups could be controlled simply by adjusting cleaning cycles, and the MB removal efficiency had a strong dependence on the pH of MXene suspension. Furthermore, the MXene exhibited relatively good recyclability, enabling its repeated use. The adsorption capability of the MXene was revealed to become weaker for the other organic dyes. The results of this work may give an insight into practical application of MXene for remediation of polluted water.