Preparation and hydrophobic modification of carboxymethyl chitosan aerogels and their application as an oil adsorption material

Abstract

Carboxymethyl chitosan (CMCS) aerogels were prepared through sol-gel combining with freeze drying technology. The effects of CMCS concentration on the gelation time, volume shrinkage, density, porosity, compressive strength and hygroscopicity were investigated. Meanwhile, the CMCS aerogel was characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Then the CMCS aerogel was hydrophobic, modified through cold plasma modification technology, and oil absorbency of hydrophobic modified CMCS (HMCMCS) aerogel was researched. The results showed that the CMCS aerogel had the lowest density of 0.022 g/cm3, the maximum porosity of 95.34%, the highest compressive strength reached 1.74 MPa and a three-dimensional (3D) network heterogeneous porous structures in the inner areas. After hydrophobic modification, the water contact angle of 2% for HMCMCS aerogel with 20 min under 60 W reached 117 °. Besides, the HMCMCS aerogel represented excellent oil adsorbing property and outstanding recyclability, for the oil adsorption rate was up to 31.6 g/g and stable in multiple cycles.