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

Abstract

Chitosan is a typical hydrophilic biomass building block widely used in material science and engineering. However, its intrinsic amphiphilicity has been seldom noted so far. Herein, a series of glutaraldehyde-crosslinked chitosan cryogels with superamphiphilicity are fabricated at moderately frozen conditions through a freezing−thawing process. The micron-sized porous cryogel samples display a 0°contact angle toward both water and oil, 0°water contact angle under oil, and over 120°oil contact angle underwater. By comparing the wetting behavior of the tablet compressed by pure chitosan powders, the superamphiphilicity of the chitosan sample is proven to be independent on crosslinkers. This special wettability endows the chitosan cryogels with high separation efficiency for various surfactant-stabilized oil-in-water emulsions under continuous flow mode driven by gravity as well as a peristaltic pump.

Chitosan Glutaraldegyde Cryogels for Wastewater Treatment and Extraction of Silver Nanoparticles

“…Previously, some research has been conducted regarding the application of CHI-GA cryogel for oil recovery from an aqueous suspension. It was stated that the gel yields reached only 80% and were independent of crosslinking agent content (0.1-0.5%) for 2.0 vol.% chitosan loading [47]. In the current study, the process of AgNP removal with the help of CHI-GA cryogel was studied.…”

Chemical and Photochemical-Driven Dissipative Fe3+/Fe2+-Ion Cross-Linked Carboxymethyl Cellulose Gels Operating Under Aerobic Conditions: Applications for Transient Controlled Release and Mechanical Actuation

“…The cryo-conditions lead to the formation of crystalline solvent domains coated by surrounding concentrated cross-linked polymer scaffolds that, upon defrosting, yield gel matrices with interconnected solute macropores embedded in the polymer framework . The interconnected macropores comprising the cryogels yield solvent channels in the framework, introducing significant physical properties as compared to the hydrogel, reflected by material compressibility, , different mechanical strengths, , and most importantly, convection transport of the solute across the channels, , as compared to diffusion-controlled transport of the solute in hydrogel matrices. These features lead to substantially faster response times for the stimuli-responsive cryogels as compared to those of analogue hydrogels …”

Stiffness‐Switchable, Biocatalytic pH‐Responsive DNA‐Functionalized Polyacrylamide Cryogels and their Mechanical Applications

“…These are reflected by different mechanical strengths [61,62] and compressibilities [63] of the cryogels originating from the higher polymer content in the framework boundaries, and the solute squeezability, [64,65] of the interconnected macropores comprising the cryogels. In addition, the large interconnected solute macropores, allow the convectional transport of solute in the cryogels, [66][67][68][69][70] as compared to diffusionally-hindered transport in hydrogels, leading to enhanced mass-transport of the solute inside the cryogel and between the cryogel and its surrounding. These features of cryogels lead to enhanced physical and chemical responses of the cryogels as compared to hydrogels.…”