Cellulose-based aerogel from wastepaper by lyophilization for the removal of oil in polluted water bodies

The present work was performed with the purpose of developing a cellulose-based aerogel with hydrophobic properties to be used as an absorbent for the removal of oil pollutants in water. The produced aerogel was obtained from waste office paper cellulose via lyophilization and used biodegradable materials to gain hydrophobicity. The physical properties of the obtained aerogels showed a high porosity value, above 90% and low densities, less than 0.15 g/cm3. These properties are essential for absorbents as they allow pollutants to permeate through their bodies filling their internal porous network. To prove the usefulness of the synthesized cellulose-based aerogels, an oil absorption capacity test was performed, the results indicate that the produced aerogels could absorb 7 times their original weight. For hydrophobicity, two types of surface modifications were performed. The first one was done with polycaprolactone achieving a water contact angle of 129°, while the second modification used candelilla wax, obtaining a contact angle of 123°, both achieved hydrophobicity by surpassing an angle of 90°. The scanning electron microscopy images provided proof of the surface modifications, while the Fourier-transform infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry experiments further demonstrated the presence of both materials in the tested samples. Lastly, the reusability of the produced aerogels was tested, the candelilla wax coating degraded after the first cycle, while the PCL coating managed to keep its hydrophobic properties and most of its absorbent capacity after 5 adsorption–desorption cycles. These results show that a cellulose-based aerogel is able to function as an oil absorbent with potential practical applications.

https://orcid.org/0000-0002-1377-3569