Superhydrophilic Sandwich Structure Aerogel Membrane for Emulsion Separation and Heavy Metal Ion Removal

Abstract

Water pollution has been increasingly becoming a serious environmental and health challenge in recent years. This is compounded by the often coexisting oil pollution and heavy metal pollution. It is of great practical significance to develop materials that can simultaneously deal with these two kinds of water pollution problems. In this study, a simple and green approach is proposed for preparing matrix-free citric acid modified alginate-based aerogel membrane by simple sol spraying, chemical cross-linking, and freeze-drying methods. The aerogel membrane with dense upper and lower surfaces and a loose interlayer possesses the properties of superhydrophilicity and underwater superoleophobic and strong antiadhesion performances, and it can realize the separation of highly viscous miscible oil–water emulsions with a separation efficiency of over 99.5%, even in corrosive and high-salt environments. The membrane has shown strong stability during 3000 min of uninterrupted cross-flow filtration of emulsion, which reflects the good long-term separation performance of the membrane. The prepared membrane can also be used for the removal of various heavy metal ions from water under gravity, with a removal efficiency >99% and an adsorption capacity of about 240 mg/g for Pb2+. The modified membrane which features low cost, a simple and green preparation process, excellent oil–water separation, and heavy metal removal capabilities possesses great application potential in the treatment of polluted water.

Synergistic Effect of Functionalization and Crystallinity in Nanoporous Organic Frameworks for Effective Removal of Metal Ions from Aqueous Solution

“…To more precisely describe the adsorption kinetics and test its anti-interference ability, we then plotted the adsorption isotherms of TPPA-SO 3 H to Fe 3+ , Cr 3+ , and Cd 2+ ions against the initial concentrations and adsorption times (Figure e,f). , The studies of the pH value effect revealed that TPPA-SO 3 H showed the most excellent adsorption capability to all three ions under near neutral conditions (pH ≈ 6.5, Figure S16). Meanwhile, the imine bonds are easily hydrolyzed under strongly acidic and basic conditions.…”

“…Membrane filtration as a simple and easy ion removal method has wide applicability in industry. , We then pressed the powders of three samples into three membranes with diameters of about 2.0 cm (Figure a–c) and tested their capabilities for removal of metal ions by membrane filtration separation methods. Before each membrane is fixed in the middle of the home-made equipment, as shown in Figure d, the water contact angle was first tested.…”

Nature-Inspired Polyethylenimine-Modified Calcium Alginate Blended Waterborne Polyurethane Graded Functional Materials for Multiple Water Purification

“…Fabrication of GPM Purification Material. According to a previous report, 37 the above prepared sols were uniformly sprayed onto the ice surface of calcium chloride (2%) to form solid sol. In particular, the SA sol and SA@PEI@WPU blended sol were sprayed in stages.…”

“…On the basis of our previous work, a kind of graded functional purification material was designed in this study to purify complex sewage through filtration. As shown in Figure , the purification material herein reported has a secondary structure, consisting of an SA@WPU@WPU functional layer and an SA isolation layer.…”

Flexible Aerogel Materials: A Review on Revolutionary Flexibility Strategies and the Multifunctional Applications

“…Zhang et al reported a citric acid free modified alginate based aerogel film, which possessed a hierarchical microstructure with dense upper and lower surfaces and loose middle layers as shown in Figure 23b. 220 The prepared aerogel film exhibited super hydrophilic and underwater super oil repellent properties and strong adhesion resistance and could realize the separation of highly viscous miscible oil−water emulsions even in a orrosive and high salt environment, and the separation efficiency was more than 99.5%. In the process of continuous cross-flow filtration of emulsion for 3000 min, the membrane showed strong stability, which reflected that the membrane had good long-term separation performance.…”