Lotus-Root-like Supermacroporous Cryogels with Superphilicity for Rapid Separation of Oil-in-Water Emulsions

Abstract

The separation of surfactant-stabilized oil-in-water emulsions is a challenging issue as such state-of-art technologies usually suffer from energy-intensive, time-consuming, and inefficient processes. Here, we constructed a series of superphilic cryogels of regular, ordered, and oriented porous structures that are similar to that of lotus root. Using dimethyl sulfoxide as a solvent and its crystals as porogens, monolithic cryogels were obtained by polymerization of polyethylene glycol diacrylate (PEGDA) embedded with polydivinylbenzene (PDVB) particles at the nondeeply frozen condition. The as-prepared cryogels were of interconnected micrometer-sized porous structure in the range of several micrometers to several tens of micrometers in pore diameter. The pristine polyPEGDA cryogels displayed superphilicity in air, superhydrophilicity under oil, and oleophobicity underwater, and the addition of PDVB particles into the matrix increased the surface roughness and thus led to a higher oleophobicity underwater as well as an enhancement in mechanical strength. The composite cryogels showed a rapid separation of the surfactant-stabilized oil-in-water emulsion with high separation efficacy up to 99.9% driven solely by gravity, and they exhibited a good recyclability after eight time treatments. Owing to the combination of the special interfacial interactions and pore-size effect, the three-dimensional supermacroporous monoliths with superwettability are a potential alternative for separation of oil-in-water emulsion with high separation efficacy and low cost.

Janus Membranes with Asymmetric Wettability Applied in Oil/Water Emulsion Separations

“…polymerized polydivinylbenzene particles with PEGDA to form lotus‐root‐like super‐macroporous cryogels under the nondeeply frozen condition to rapidly separate oil‐in‐water emulsions. [ 83 ] The cryogel had superphilicity in air, superhydrophilicity under oil, and higher oleophobicity under water, which separated the water from the oil‐in‐water emulsion under gravity, with the separation efficiency of 99.9% and good recyclability after eight treatments. Similarly, the asymmetric wettability of Janus membranes prepared by gel also has outstanding advantages in the separation of oil/water emulsions.…”

“…Reproduced with permission. [ 83 ] Copyright 2017, Wiley‐VCH Verlag GmbH & Co. KGaA. c) Microscopic images of oil droplets at different demulsification times in the BPEF with its voltage 900 V, frequency 50 Hz, and duty cycle 0.5.…”

“…Copyright 2007, Elsevier B.V. b) Ideal cross-sectional structure for an oil droplet stabilized by a free surfactant and the grafted copolymer polysoap bearing pendant oligo (ethylene glycol) monolaurate (EL) chains. Reproduced with permission [83]. Copyright 2017, Wiley-VCH Verlag GmbH & Co. KGaA.…”

Biomass-based materials for green lithium secondary batteries

“…1). [70][71][72][73][74][75][76][77][78][79][80][81][82] In short, biomass can be transformed into functionalized scaffolds for optimizing cathode/anode materials or itself function as the active material. Moreover, there have been mature procedures to extract natural chemicals [carbohydrates (starches, terpenes, low-molecular sugars), celluloses, hemicelluloses, lignins, uronic acids, oil, proteins, etc.…”

Preparation of Dextran Cryogels and Some of Their Applications

“…Cryogels have superior properties such as fast swelling-shrinkage, high mechanical strength and elasticity (Sengel et al, 2017;Suner et al, 2019;Tavsanli and Okay., 2020). Because of these innate properties, cryogels are commonly used in biomedical fields including tissue engineering, drug carrier systems, immunotherapy as well as having applications in environmental use such as separation and purification (Sahiner and Demirci, 2016;Sahiner et al, 2017;Topuz and Uyar, 2017;Ciolacu et al, 2016;Hixon et al, 2017;Akilbekova et al, 2018;Guo et al, 2019).…”