Sustainable, Highly Efficient and Superhydrophobic Fluorinated Silica Functionalized Chitosan Aerogel for Gravity-Driven Oil/Water Separation

Abstract

A superhydrophobic fluorinated silica functionalized chitosan (F-CS) aerogel is constructed and fabricated by a simple and sustainable method in this study in order to achieve highly efficient gravity-driven oil/water separation performance. The fluorinated silica functionalization invests the pristine hydrophilic chitosan (CS) aerogel with promising superhydrophobicity with a water contact angle of 151.9°. This novel F-CS aerogel possesses three-dimensional structure with high porosity as well as good chemical stability and mechanical compression property. Moreover, it also shows striking self-cleaning performance and great oil adsorption capacity. Most importantly, the as-prepared aerogels exhibits fast and efficient separation of oil/water mixture by the gravity driven process with high separation efficiency. These great performances render the prepared F-CS aerogel a good candidate for oil/water separation in practical industrial application.

Bioinspired Multiscale Micro-/Nanofiber Network Design Enabling Extremely Compressible, Fatigue-Resistant, and Rapidly Shape-Recoverable Cryogels

“…The cryogel can be made into various 3D shapes such as pentagram, square, 3D-molded crab, and sphere, exhibiting excellent formability (Figure 1F). More attractively, benefiting from the synergistic effect of microfibers and nanofibers, the obtained CMNF cryogel presents high compressibility (97% strain with 50 cycles), outstanding fatigue resistance, and rapid watertriggered shape recovery (in ∼1 s), outperforming previously reported gel materials such as chitosan/polymer composite cryogels/hydrogels, 8,14−19 chitosan/inorganic matter composite cryogels/hydrogels, 4,20,21 and other polymeric cryogels/ hydrogels 9,22−29 in terms of compression cycle numbers and corresponding ultimate compression strain (Figure 1G). Interestingly, this flexible CMNF cryogel shows excellent adsorption and assembly capacities for nanoscale building blocks, ranging from zero-dimensional (0D), one-dimensional (1D), and two-dimensional (2D) to three-dimensional (3D) nanoparticles.…”

“…(F) Optical photographs of CMNF cryogels with diverse shapes. (G) Comparison among the CMNF cryogel and previously reported gel materials including chitosan–polymer composite cryogels/hydrogels, ,− , chitosan–inorganic matter composite cryogels/hydrogels, ,, and other polymeric cryogels/hydrogels ,− in terms of compression times and corresponding compression strain.…”

Modification of chitosan with cellulose and gelatin for the removal of Cu2+, Fe2+, and Pb2+ from oily wastewater

“…It is worth noting that the functionalized surface retains its porous shape (with micro‐sized pores). [ 39 ] Figure 5D–F shows cross‐sectional topologies of chitosan membranes with almost the same three‐dimensional structure and large porosity, revealing that surface functionalization happened solely on the surface. It has been found that separation polymers with high adsorption capacity and high porosity can give excellent oil/water removal efficiency.…”

“…It has been found that separation polymers with high adsorption capacity and high porosity can give excellent oil/water removal efficiency. [ 39 ] The chitosan surface was already rougher. It remained rough after alteration but with more irregularly shaped particles, which was linked to the breakage of hydrogen bonding, resulting in microfibrils.…”

Superamphiphilic Chitosan Cryogels for Continuous Flow Separation of Oil-In-Water Emulsions

“…We noted that chitosan is well known as a kind of hydrophilic building block. In order to achieve separation of oil/water mixture or emulsion, several chitosan aerogels are reported to convert their hydrophilic surfaces into hydrophobic ones before treatment of wastewater. − During our preliminary tests on chitosan-based cryogels, we unexpectedly observed that the near chitosan cryogels displayed superamphiphilic wetting behavior because the samples show 0° contact angle toward both water and oil in air. Based on the literature and our previous experience, ,, the superamphiphilic foams are of high separation efficacy of oil-in-water emulsion.…”