Macroporous cellulose microspheres derived from cigarette butts waste: preparation, characterization, and application in proteins adsorption

Cigarette butts properly serve as one of the most commonly littered wastes in the social world. Instead of landfilling and incineration, identifying a methodologically feasible way to valorize cigarette butts with the more considerable value is crucial. In this context, we efficiently utilize cellulose acetate from cigarette butts as the precursor to prepare macroporous cellulose microspheres through an emulsion-evaporation-induced phase separation method, together with deacetylation. The results reveal that these macropores with a size of about 100 nm are created by the evaporation of the solvent during the emulsion. And the pore size is controlled by adjusting the fabrication parameters. To demonstrate the practical potential of macroporous cellulose microspheres, they were chemically modified by sodium alginate to achieve a cationic adsorbent. It is worth mentioning that the sodium alginate-modified macroporous microspheres display excellent adsorption capacity of 110.5 mg/g for lysozyme, rapid separation (equilibrium within 30 min) and excellent mechanical strength. The proposed low-cost and eco-friendly macroporous cellulose microspheres are considered to be green and sustainable, and have great potential for bio-separation.