3D hierarchical MnO₂ aerogels with superhydrophobicity for selective oil–water separation

Abstract

Inorganic nanowire aerogel with low density, high specific surface area and high porosity has received increasing attention in the field of materials physics and chemistry because of not only the unique structural and physical features of metallic oxide but also low cost, environmental friendliness and earth abundant of precursor materials. In this work, MnO2 nanowire aerogels (MNA) with ultralow density, and stable 3D hierarchical structures was successfully fabricated by freeze‐drying processes using MnO2 nanowire as building blocks. The length of MnO2 nanowires exceeds 100 μm, making it easier to cross‐link and self‐assemble into a 3D network of aerogels, and the acid and alkali resistance of MnO2 enables it to adapt to extreme environments. Simultaneously, the monodispersed MnO2 nanowire was prepared by the hydrothermal method, followed by acid treatment. To obtain superhydrophobic properties and achieve selective oil adsorption, the surfaces of nanowire aerogels were grafted the hydrophobic groups with low surface energy via vapor deposition. It is indicated that the obtained 3D hierarchical MNA show both superhydrophobic and super‐lipophilic properties simultaneously with a high‐water contact angle of 156° ± 2° and an oil contact angle of 0°. And the MNA exhibited a high oil adsorption capacity of 85–140 g/g, thereby indicating its potential applications in oil/water separation. More importantly, the resulting MNA can be recycled ten cycles without loss of oil absorption capacity (more than 120 g/g). The results presented in this work demonstrate that the as‐prepared nanowire aerogel may find applications in chemical separation and environmental remediation for large‐scale absorption of oils from water.

In Situ Redox Strategy to Fabricate Superhydrophobic Sponges for Efficient Oil–Water Separation

“…Manganese dioxide (MnO 2 ), an inorganic nanomaterial with a high surface area and unique morphology, is suitable for fabricating rough structures. 21,22 However, MnO 2 nanoparticles are prone to aggregation. As a material for building the rough structure of sponges, they can easily block the pores of the sponges and affect their oil absorption capacity.…”

Design and Performance Comparison of Polymer-Derived Ceramic Ambigels and Aerogels

“…Aerogels are highly porous materials containing mostly air in their structure (usually above 80 vol %), having submicron pores resulting in medium to high specific surface area (SSA) (∼100–1000 m 2 g –1 ) and thus relatively low densities below <0.5 g cm –3 . – A number of aerogel types have already been investigated for applications, including catalysis, sensors, , thermal , and electric insulation, wastewater management, , energy storage, , electromagnetic absorber, and drug delivery …”

Durable 3D Porous Superhydrophobic Composites for Versatile Emulsion Separation in Multiple Environments

“…However, current methods of dealing with both types of contaminations are relatively primitive and time-consuming . Although there are a variety of new materials available for water pollution treatment, such as hydrogels, , aerogels, − and inorganic adsorbents, − due to their cost and the fact that the preparation process is not environmentally friendly, there are still gaps in their practical application.…”