Highly Hydrophobic All-Biomass Aerogels with Advanced Oil Absorption and Recyclability

Abstract

Biomass resources are abundant, diverse, and widely available in nature. The renewable and environment-friendly nature of biomass resources is in line with the theme of sustainable development of society. Herein, we report a facile and environmentally friendly route to prepare highly hydrophobic biomass aerogels for the adsorption of oil and organic solvents. The main features of our preparation approach are reflected by the use of natural animal gelatin and water-soluble chitosan as raw materials and dialdehyde carboxymethyl cellulose (DCMC) as a cross-linking agent through effective cross-linking between the aldehyde group and amino group, followed by hydrophobic coating of natural wax to create an entire biomass-based hydrophobic aerogel. The results showed that the WC-Gel/CMCS/DCMC aerogel had low density (12.3 mg/cm3), high porosity (>95%), and high hydrophobicity (144.2°). In addition, the aerogel can rapidly and selectively adsorb oil substances in oil–water mixtures and has a high absorption capacity (27.5∼46.2 g/g). The adsorption–extrusion repeated tests showed that the material has good adsorption performance and recyclability for various oil-containing liquids and organic solvents. Overall, the as-prepared biomass composite aerogel has great potential for application in the field of oil–water separation. The constructive concept of preparing composite aerogels by a simple method using biomass substrates also provides ideas for the development of biomass-based functional materials.

A Novel, Controllable, and Efficient Method for Building Highly Hydrophobic Aerogels

“…Aerogels made from silane [1][2][3][4][5], carbon [6][7][8][9], biomass [10][11][12][13][14][15][16][17][18][19][20][21][22][23], polymers [24][25][26], metal oxides [27], inorganic salts [28,29], etc., have the advantages of low density, high porosity, and high specific area [18]. This combination of properties makes them have a huge number of applications in the fields of industry [30], architecture [8,31,32], agriculture [17], etc., some of which have been commercialized already.…”

“…Chemical vapor deposition (CVD) is a feasible method, with the obvious advantages of effect and size retention, but it cannot rebuild rough morphology. In fact, according to the Wenzel model, the hydrophobicity of the surface is highly dependent on the roughness [18,21]. Adding or coating nano-micro-materials is an effective method, but it complicates the process and increases the cost.…”

Peroxidase-Catalyzed Fabrication of a Mechanically Robust Nanofibrillated Cellulose-Based Aerogel with Antibacterial Activity for Efficient Oil–Water Separation

“…In recent years, large amounts of industrial wastewater containing organic pollutants discharged from petrochemicals, textiles, and food industries have exacerbated the scarcity of clean water resources. − Therefore, the efficient separation of oil–water mixtures and recycling of water resources are urgently increasing. Various techniques have been utilized for oil–water separation, such as gravity separation, centrifugal separation, incineration, chemical flocculation, bioremediation, and oil adsorption. − Among them, physical oil adsorption method is commonly considered as a relatively economical and effective way to treat oily wastewater . Many hydrophobic and lipophilic materials such as carbon-based materials, polytetrafluoroethylene-coated meshes, polymeric porous materials, and polydimethylsiloxane-coated nanowire films, have been developed for the adsorption of residue oil from oily wastewater. − However, due to their inherent lipophilic nature, it is difficult to effectively separate the adsorbed oil from the interior of the above-mentioned materials, which easily leads to scaling on the material surfaces or blocking the internal porous structures, affecting the reuse effect of the oil-adsorbing materials .…”