Adsorption characteristics of directional cellulose nanofiber/chitosan/montmorillonite aerogel as adsorbent for wastewater treatment

Currently, the preparation of environmentally friendly and sustainable adsorbents with excellent adsorption performance has attracted researcher's attention, because of the shortage of water resources and environmental pollution caused by wastewater pollution. In this work, we report a novel, environmentally friendly and simple liquid nitrogen directional freezing method in which acid-modified montmorillonite was introduced into the cellulose nanofiber/chitosan system to successfully prepare cellulose nanofiber/chitosan/montmorillonite aerogel (CCMA). Compared with other aerogels, CCMA forming a homogeneous three-dimensional directional pore structure, showing excellent mechanical properties, good adsorption performance and reusability. The results show that the aerogel can withstand heavy objects 1124 times own weight, while maintaining a stable structure in a strong acid environment. The most important thing is that the adsorption capacity for Cu2+, Pb2+ and Cd2+ can reach 181.92 mg/g, 170.19 mg/g and 163.85 mg/g. Moreover, the aerogels could retain 80% of their initial adsorption capacity after 5 cycles. CCMA has the opportunity to become a good adsorbent for adsorbing heavy metal ions.