Robust and Versatile Cellulose Aerogel with a Self-Wettable Surface for Efficient Dual Separations of Oil-in-Water and Water-in-Oil Emulsions

Abstract

Separation materials with unique surface wettability have been regarded as promising candidates for oily sewage treatment. However, simple and facile fabrication of superwettable materials integrating robust and tunable surface features is still a challenge. Inspired by the unique molecular structure of cellulose with a rigid skeleton and abundant hydroxyl groups, this work proposed highstrength, superhydrophilic, and underwater superoleophobic cellulose aerogels prepared via facile chemical cross-linking without any surface modification. Benefiting from the superporous microstructure and unique surface wettability, the cellulose aerogels exhibited on-demand separation performances for oil-in-water (O/W), water-in-oil (W/O) emulsions, and crude oil. The superior separation flux of 19,602 L/ (m 2 h) and a rejection of 99.5% were acquired for O/W emulsion, while 5158 L/(m 2 h) of flux and 98.9% of rejection were acquired for W/O emulsions. Importantly, the cellulose aerogels show an outstanding efficiency for crude oil/water emulsions with flux from 7815 to 26,648 L/(m 2 h) based on water content. Moreover, owing to the rigid skeleton and cross-linked cellular architecture, the aerogels displayed significant flexibility and toughness with tiny deformation of 0.15% after 60 cycles underwater, endowing it with excellent reusability. Thereby, this proposed cellulose aerogel with unique advantages of a robust, superhydrophilic, and underwater superoleophobic surface exhibits a promising application in versatile and efficient dual oil/water separation.

Designing magnetic and superhydrophobic cellulose nanofibers based‐aerogel for efficient oil water separation

“…Efficient adsorbents usually exhibit high capacity, a substantial specific surface area, low density and robust oilwater selection. [11][12][13][14] Ren et al prepared graphene aerogels with ultra-low density, excellent compressibility and hydrophobicity by introducing water-soluble polyimides into graphene, enabling the rapid and efficient separation of oil and water. 15 Wang et al introduced two-dimensional MXene into polyimide (PI), followed by freeze-drying and hot imylation to obtain a sturdy, lightweight, and hydrophobic three-dimensional structure.…”

“…Efficient adsorbents usually exhibit high capacity, a substantial specific surface area, low density and robust oil–water selection 11–14 . Ren et al prepared graphene aerogels with ultra‐low density, excellent compressibility and hydrophobicity by introducing water‐soluble polyimides into graphene, enabling the rapid and efficient separation of oil and water 15 .…”

Magnetic Hyperporous Elastic Material with Excellent Fatigue Resistance and Oil Retention for Oil–Water Separation

“…Oily wastewater is a serious threat to the environment, especially to water resources, raising urgent demands for effective strategies for oil–water separation. − The commonly used oil–water separation technologies mainly include combustion, purification, membrane technology, and absorption. − Among them, absorption is the most potential development direction at present due to the advantages of recoverability and low secondary pollution to the environment. Traditional absorbents commonly exploit porous materials such as activated carbon, , aerogel, − modified sponge, − fabrics, − etc. In particular, sponges with interconnected pores have gained widespread attention due to their large absorption capacity, high efficiency, and good mechanical properties as well as multifunctionalities. − However, the following challenges still exist in practical applications.…”

Study of Salidroside and Its Inflammation Targeting Emulsion Gel for Wound Repair

“…The emulsion is a biphasic formulation that consists of immiscible dispersed and dispersion phases stabilized via an emulsifier. Several types of emulsions, such as particle-stabilized oil/water and water/oil emulsions, have been fabricated for various applications in pharmaceuticals [ 14 , 15 ]. Emulsion gel systems have advantages over emulsions and hydrogels in their application.…”