A high-performance adsorbent of 2D Laponite in-situ coated on 3D diatomite for advanced adsorption of cationic dye

A one-step hydrothermal method was used to synthesize two-dimensional layered Laponite nanosheets (Laponite@diatomite) in situ on the three-dimensional biological template diatomite. The cationic dye removal ability of Laponite@diatomite with different diatomite content was studied. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transformed-infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and N 2 adsorption-desorption technology were used to characterize synthetic materials. The effects of pH, initial concentration, dynamics, and thermodynamics behavior on the adsorption performance were further studied. La@D-0.1 had the highest adsorption efficiency, and the adsorption rate of methylene blue (MB) solution (450 mg L −1 ) reached 76.7% in the initial 5 min. At the time of adsorption equilibrium (1 h), methylene blue adsorption rate reached 86.4%. The adsorption behavior of La@D-0.1 on MB was characterized by Langumuir isotherm and with better fitting to the quasi-second-order kinetic model curve. By calculating the adsorption process’s thermodynamic parameters, we were able to illustrate that the adsorption process was exothermic. This work provides a novel idea for the synthesis of an economical and ideal, cationic dye nano-adsorbent and provides a potential application for the purification of actual dye wastewater.