Lightweight hydrophobic cellulose foam material with low density and high porosity applications in Cu (II) adsorption

Abstract Cellulose foam, renowned for its lightweight properties and exceptional adsorption capacity, has emerged as a significant material of interest. In our study, a distinct functionalized cellulose foam adsorbent was developed using N , N ‐methylenebisacrylamide (MBA) as a cross‐linker. This foam was further chemically tailored with 3‐aminopropyltriethoxysilane (APTES) and tannic acid (TA) to optimize its affinity for Cu (II). Utilizing a green and efficient procedure at ambient temperature, MBA was directly crosslinked with MCC sol, the resultant foam features a distinguished three‐dimensional, multi‐walled porous configuration, marked by a strikingly low average density of 0.0306 g/cm 3 and an impressive average porosity surpassing 97%. Subsequently, more amino and oxygen‐containing groups were introduced by simple impregnation. The rich functional groups and unique structure enabled the adsorption of Cu (II) up to 93 mg/g, demonstrating an increasing trend in line with rising Cu (II) concentrations. Furthermore, this composite cellulose foam displayed commendable hydrophobic characteristics, evident from a hydrophobic angle surpassing 120°. From both environmental and economic perspectives, this chemically‐modified cellulose material epitomizes an ideal adsorbent, showcasing unparalleled adsorption capacity coupled with robust chemical and structural integrity. As such, it presents a viable option for the efficient sequestration of Cu (II) in wastewater treatments.