Enhanced Potential Toxic Metal Removal Using a Novel Hierarchical SiO2–Mg(OH)2 Nanocomposite Derived from Sepiolite

Abstract

Clays are widely used as sorbents for heavy metals due to their high specific surface areas, low cost, and ubiquitous occurrence in most soil and sediment environments. However, the low loading capacity for heavy metals is one of their inherent limitations. In this work, a novel SiO2–Mg(OH)2 nanocomposite was successfully prepared via sequential acid–base modification of raw sepiolite. The structural characteristics of the resulting modified samples were characterized by a wide range of techniques including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and nitrogen physisorption analysis. The results show that a hierarchical nanocomposite constructed by loading the Mg(OH)2 nanosheets onto amorphous SiO2 nanotubes can be successfully prepared, and the nanocomposite has a high surface area (377.3 m2/g) and pore volume (0.96 cm3/g). Batch removal experiments indicate that the nanocomposite exhibits high removal efficiency toward Gd(III), Pb(II), and Cd(II), and their removal capacities were greatly enhanced in comparison with raw sepiolite, due to the synergistic effect of the different components in the hierarchical nanocomposite. This work can provide a novel route toward a hierarchical nanocomposite by using clay minerals as raw material. Taking into account the simplicity of the fabrication route and the high loading capacities for heavy metals, the developed nanocomposite also has great potential applications in water treatment.

Efficient Removal of Cd(II) Using SiO2-Mg(OH)2 Nanocomposites Derived from Sepiolite

“…The preparation process of the material refers to the research of Yao et al [26]. Specific steps are as follows: 4.0 g of sepiolite was first added to 100 mL of 20% (v/v) HCl solution, performing acid activation for 24 h with a stirring speed of 300 r/min, and then ammonia water was added dropwise to the solution under magnetic stirring until the pH of the solution reached 10.0.…”

“…Chen et al [25] studied and summarized the latest preparation strategies, properties and applications of magnetic nanoparticle/clay mineral (MNP/CM) nanocomposites and proposed that MNP/CM nanocomposites have excellent magnetic properties, stability, adsorption, catalytic properties, biocompatibility and good application prospect. Yao et al [26] carried out sequential acid-base composite modification of sepiolite to prepare SiO 2 -Mg(OH) 2 nanocomposites, which exhibited high removal efficiency toward Gd(III), Pb(II) and Cd(II). Sepiolite is a natural nanomaterial with a relatively stable structure and an excellent carrier for other nanoadsorbents [27,28].…”

Removal of heavy metal ions by porous sepiolite‐based membrane

“…Thus, many studies have been conducted to develop low‐cost adsorbents from cheap and readily available materials. Natural clay minerals, such as zeolites [20], kaolinite [21], montmorillonite [22, 23], bentonites [24] and sepiolite [25, 26] etc. have a complex porous structure with high specific surface area, which allow strong physical and chemical interactions with heavy metal ions.…”

Editorial for Special Issue “Nanomineralogy”

“…The other articles [28][29][30][31][32] in this special issue are devoted to ore deposits and mineral materials. The genesis of Carlin-type gold deposits is analyzed at the nano scale; the significance of using metallic nanoparticles to search for concealed deposits is discussed; and the preparation, characterization, and physicochemical properties of nanomineral materials are explored.…”

“…Although clays are widely used as sorbents for heavy metals due to their high specific surface areas, low cost, and ubiquity in most soil and sediment environments, they still face inherent limitations owing to the low loading capacity of heavy metals. Yao and coauthors [31] studied enhanced potential toxic metal removal using a novel hierarchical SiO 2 -Mg(OH) 2 nanocomposite derived from sepiolite. The structural characteristics of the resulting modified samples were characterized by a wide range of techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and nitrogen physisorption analysis.…”