Macroporous Aerogels Using High Internal Phase Pickering Emulsions for Adsorption of Dyes

Abstract

The treatment of industrial printing and dyeing wastewater is the focus of the chemical environmental protection industry. Noticeably, the physical adsorption has attracted wide attention due to the selective dye adsorption, simple process, and convenient operation. New aerogels featuring low density and high porosity are regarded as ideal physical adsorption materials for sewage treatment. In this work, high internal phase Pickering emulsions were designed and prepared. The polysaccharide complex originating from sodium octenylsuccinate starch and chitosan serves as the stabilizer, water and hexane act as the external and internal phase, respectively. Acrylic acid was introduced into the external phase to initiate UV polymerization. The high internal phase Pickering emulsions as templates were removed through freeze-drying to produce aerogel materials with macroporous structures, the size of the pores: 43.54 ± 12.75 μm. The scanning electron microscopy (SEM) images show that the pore size of aerogel materials was similar to that of emulsion droplets, verifying the template role of emulsion in the polymerization process. In addition, aerogels possess good mechanical properties and can withstand a pressure of megapascal, exhibiting favorable stability when floating in water for a long time (6 months). Methyl violet, malachite green, methylene blue, and acridine orange in aqueous solution were selected as model dyes to explore the removal process and the mechanism. The adsorption was conformed to be the pseudo-second-order kinetic model and the Freundlich adsorption isotherm, namely, the dye adsorption of the aerogels was the multilayer adsorption on the uneven surface, and the mechanism of the adsorption was related to the π–π interaction.

Particle–Polymer Union with Changeable Wettability for Constructing Bijels Using a Simple Mixing Method

“…After the semidried process, as shown in Figure c–e, wrinkles appeared on the surfaces of emulsion droplets for all three samples. This phenomenon was a typical characteristic of the Pickering emulsions because the particles as stabilizers were firmly adsorbed at the water–oil interface to form rigid elastic films in order to decrease the interfacial energy, for which the desorption of particles to disperse in liquid phases was a very difficult process . Thus, during the volatilization of water and toluene, with the shrinkage of the droplet surfaces, folded films with deformed morphologies of droplets could be presented.…”

Design of Infused-Liquid-Switchable Superamphiphilic and Flame-Retardant Hierarchically Porous Materials from Emulsion-Templated Technique

“…To determine the mechanical property of polyHIPE@PSZs, the samples were compressively tested (Figure S11). The E values of polyHIPE@PSZ-1, polyHIPE@PSZ-2, polyHIPE@PSZ-3, and polyHIPE@PSZ-4 were 0.30 ± 0.02, 0.22 ± 0.09, 0.15 ± 0.05, and 0.10 ± 0.01 MPa, respectively, which is higher than those of the reported foam that could be used for water treatment, reflecting that the as-prepared polyHIPE@PSZs are mechanically stable to be used for oil–water separation. The stability of polyHIPE@PSZs in harsh environments, such as acid, alkali, and salt corrosion, was also tested.…”

Biobased Aerogels Fabricated by the Ice Crystal Method for Smoke Purifying

“…34−36 Our group previously adopted a high internal phase Pickering emulsion as template to fabricate macroporous aerogels for the adsorption of dyes in water, which needed a complicated preparation process. 33 Lei's group utilized the Sonogashira-Hagihara cross-coupling reaction to prepare conjugated microporous polymers with a 3D porous network structure, which showed high PM 2.5 removal efficiency and excellent antibacterial activity. 37,38 However, the preparation process required toxic organic solvent, which was not environmental-friendly.…”

“…Aerogel is a desirable porous purification material for polluted air, with interconnected three-dimensional (3D) solid networks and huge amounts of air-filled pores, possessing excellent properties such as low density, excellent specific surface area, and high porosity. − In general, aerogels can be fabricated by diverse approaches, such as hydrothermal method, − Pickering emulsion template, − and 3D printing. − Our group previously adopted a high internal phase Pickering emulsion as template to fabricate macroporous aerogels for the adsorption of dyes in water, which needed a complicated preparation process . Lei’s group utilized the Sonogashira-Hagihara cross-coupling reaction to prepare conjugated microporous polymers with a 3D porous network structure, which showed high PM 2.5 removal efficiency and excellent antibacterial activity. , However, the preparation process required toxic organic solvent, which was not environmental-friendly.…”