Double-network cross-linked aerogel with rigid and super-elastic conversion: simple formation, unique properties, and strong sorption of organic contaminants

Novel adsorbents with high adsorption capacity, broad-spectrum adsorption performance, and good reusability are needed for the treatment of diverse and complex contaminants in water. In this work, we used in situ hydrothermal reaction to fabricate graphene oxide (GO) and poly(vinyl alcohol) (PVA) based aerogels (GP(X)A, X represented the volume of PVA) through the cross-linking network that meets the above requirement. After adding Ca2+, GP(16)A (with 16 mL PVA) had surprisingly rigid and super-elastic conversion that is dependent on water stimulus. The strong adsorption of methylene blue (MB) on GP(16)A illustrated that it had excellent dye removal ability. The adsorption capacity of GP(16)A to MB was 698.38 mg g(-1) and it remained 85.62% after repeated adsorption-desorption cycles. The adsorption was controlled by multiple mechanisms including electrostatic interaction, pi-pi interaction, and hydrogen bond. In addition, hydrophobically modified GP(16)A (GP(16)A-MTMS) effectively absorbed common oils and organic solvents. Repeated absorption of GP(16)A-MTMS was re-activated by squeezing operation. This study provides an alternative technique for preparing aerogel materials with high recyclability, dimensional stability, and solvent resistance, and for dealing organic contaminants in water.

Automated summary

This study fabricated graphene oxide and poly(vinyl alcohol) based aerogels using in situ hydrothermal reaction, which exhibited excellent adsorption performance and reusability. The aerogels showed strong adsorption of methylene blue and other contaminants via multiple mechanisms. The study provides an alternative technique for preparing aerogel materials with high recyclability and dealing with organic contaminants in water.