Bentonite-assisted construction of magnesium-silicate-based composite as efficient adsorbent for organic dye removal

Abstract

Fabricating highly efficient and low-cost absorbents to remove organic contaminants in industrial effluents is urgent yet of great importance. Herein, a facile one-pot hydrothermal approach was developed to successfully construct magnesium silicate and bentonite composite (MS-Bt) with uniform multilayer porous structure by using Bt as structural promoter. The specific surface area of MS-Bt can reach up to 392 m2·g−1 along with an average pore diameter of 2.29 nm and a pore volume of 0.22 cm3·g−1. MS-Bt composite exhibits a maximal adsorption capacity of 253.92 mg·g−1 for methylene blue (MB) in model wastewater treatment. Adsorption behavior fitted well with Langmuir isotherm and pseudo-second-order kinetics adsorption equations. The adsorption pathways of MB on MS-Bt mainly include chemical precipitation by Mg-OH, electrostatic attraction and surface hydroxyl functional group capture. This work is anticipated to give a new insight into constructing organic contaminants adsorbent by using clay mineral material as an auxiliary agent.