Process for cellulose-alginate core–shell microspheres fabrication and the influence of drying conditions on their structural and adsorption performances

Herein, we present a novel and straightforward process for fabricating highly porous three-dimensional cellulose microspheres. This technique relies on the mechanical agitation of bleached natural fibers in a rotating vessel at low speed, without the need for additional chemicals. The notable advantage of this process is its ease of implementation, allowing for control of various operating conditions such as the shape of the rotator, rotation speed, fiber/reagent ratio, and reaction time. As a result, the process enables the production of cellulose microspheres with high porosity, sphericity, and narrow size distribution. To enhance the durability and stability of the cellulosic beads, and to expand their potential for large-scale applications, the cellulose microspheres were encapsulated with sodium alginate, serving as a core structure. We successfully developed five different kinds of microspheres with diverse appearances by varying the drying conditions. We thoroughly investigated the effects of the operating and drying conditions on various aspects; morphology, stability, and physicochemical characteristics of the resulting microspheres. The results demonstrated that all beads exhibited fascinating characteristics with high porosity. Furthermore, the encapsulation of the cellulose beads had advantageous effects on their thermal, mechanical, and adsorption performances for methylene blue adsorption as an initial gauge of the adsorption capacity for molecules/dyes of interest.