Excellent adsorption performance for Congo red on hierarchical porous magnesium borate microsphere prepared by a template-free hydrothermal method

The hierarchical porous 2MgO center dot B2O3 center dot H2O (MBO) microsphere has been prepared by a template-free hydrothermal method, which was characterized by XRD, FT-IR, TG, SEM and TEM. The microsphere nanostructure is assembled by nanobelts array with the thickness of 10 nm and width of 10-30 nm. The possible growth mechanism of the 3D hierarchical MBO nanostructure is also proposed. It has been demonstrated that the as-prepared MBO nanostructure has a porous hierarchical structure with a high specific surface area of 93.64 m(2)/g measured by N-2 adsorption-desorption. It exhibits excellent adsorption performance with maximum adsorption capacity of 183.15 mg/g for Congo red (CR), as well as good recyclability. Moreover, the adsorption process of CR on hierarchical porous MBO was systematically investigated, which was well fitted with the pseudo-second-order rate equation and Langmuir adsorption model. It needs to indicate that the as-prepared hierarchical porous MBO microsphere can be considered as a promising candidate for wastewater treatment. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.