Synthesis of Magnesium hydroxide Whisker‐encapsulated Carbonized Chitosan and Basic Magnesium Carbonate Composite for Efficient Pb(II) Removal

Abstract

In this study, for magnesium hydroxide adsorbents, hydrothermal doping strategies were used to change their surface and structural properties to enhance adsorption. A novel adsorbent was prepared and used to remove low concentrations (<100 mg ⋅ L−1) of Pb2+ from water. The structure of the adsorbent was characterized a series of characterization methods with X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, fourier transform infrared spectroscopy, nitrogen adsorption‐desorption isotherms, and X‐ray photoelectron spectroscopy. The results showed that the adsorbent was a whisker composed of magnesium hydroxide, carbonized chitosan and basic magnesium carbonate (BMC@Mg(OH)2/CCS) with a specific surface area of 84.35 m2 ⋅ g−1, much higher than that of pure magnesium hydroxide whisker (37.84 m2/g). The adsorption isotherm, kinetic, and thermodynamic properties of the adsorbent for lead ions were studied in detail by batch adsorption. The Langmuir model fits the adsorption isotherm better, and the adsorption capacity is 416.67 mg ⋅ g−1. The adsorption mechanism, which mainly involves chemical precipitation and ligand chelation, is discussed.