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Unique Lead Adsorption Behavior of Activated Hydroxyl Group in Two-Dimensional Titanium Carbide

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journal contribution
posted on 19.03.2014 by Qiuming Peng, Jianxin Guo, Qingrui Zhang, Jianyong Xiang, Baozhong Liu, Aiguo Zhou, Riping Liu, Yongjun Tian
The functional groups and site interactions on the surfaces of two-dimensional (2D) layered titanium carbide can be tailored to attain some extraordinary physical properties. Herein a 2D alk-MXene (Ti3C2(OH/ONa)xF2–x) material, prepared by chemical exfoliation followed by alkalization intercalation, exhibits preferential Pb­(II) sorption behavior when competing cations (Ca­(II)/Mg­(II)) coexisted at high levels. Kinetic tests show that the sorption equilibrium is achieved in as short a time as 120 s. Attractively, the alk-MXene presents efficient Pb­(II) uptake performance with the applied sorption capacities of 4500 kg water per alk-MXene, and the effluent Pb­(II) contents are below the drinking water standard recommended by the World Health Organization (10 μg/L). Experimental and computational studies suggest that the sorption behavior is related to the hydroxyl groups in activated Ti sites, where Pb­(II) ion exchange is facilitated by the formation of a hexagonal potential trap.