Nanoporous Cellulose Aerogels for Methylene Blue Removal from Wastewater

Nanotechnology offers a powerful tool to overcome the issue of clean water shortage. In particular, dyestuff abundance in industrial wastewater pollutes the environment and can affect negatively even human health, entering the food chain. Indeed, adsorption represents a good strategy for dye withdrawal, and this unit operation could be optimized by using nanostructured sorbents, like aerogels, that show remarkable properties in terms of active sites availability, large surface area, low density, etc. In this work, microcrystalline cellulose aerogels were produced employing the sol-gel route followed by supercritical gel drying, combining the utilization of a bio-based source with a both highly performing and eco-friendly process. The produced aerogels were characterized and tested batchwise for methylene blue removal from water, exploring the effect of initial pH and sorbent regeneration on process efficiency; the maximum removal efficiency, in the range of the adopted operating conditions, was about 90%. Eventually, the experimental data were described using kinetic models, that further proved that cellulose aerogels are promising candidates for cationic dyes removal from aqueous solutions.