High efficient and selective removal of Pb²⁺ through formation of lead molybdate on α-MoO₃ porous nanosheets array

2D hand-like structured α-MoO₃ porous nanosheets were grown in-situ onto a capillary by a simple hydrothermal route, on which titanium dioxide seed layer was sol-dip-coated in advance. The α-MoO₃ porous nanosheets array exhibits an exceptional lead ion uptake capacity up to 1450.0mg·g^-1, and can effectively reduce Pb²⁺ concentration from 20mg·L^-1 to a low level of smaller than 3μg·L^-1, well below the acceptable limits in drinking water standards (10μg·L^-1) and can efficiently remove 99.9% lead ion within a few minutes at room temperature. Furthermore, α-MoO₃ porous nanosheets array also has high selectivity toward Pb²⁺ better than Cu²⁺, Zn²⁺, Cr³⁺ and Cd²⁺. The mechanism for adsorption was discussed according to the results of Zeta potential, IR, XPS and XRD analyses. The excellent removal performance of the array to Pb²⁺ is resulted from the electrostatic adsorption interaction and the formation of new species lead molybdate.