Application of cellulose-based flocculants in microalgae flocculation: A review

The development of green and sustainable flocculants is critical for addressing the global environmental challenge of harmful algal blooms (HABs) through algal water separation techniques. Cellulose-based flocculants have garnered significant attention due to their biodegradability, substantial potential for surface modification, natural abundance, and high flocculation efficiency. Currently, the application of cellulose in microalgae flocculation primarily involves native cellulose fibers and cellulose nanocrystals. The flocculation performance of cellulose-based flocculants can be effectively enhanced through etherification modification and graft copolymerization. However, microalgae species, culture media, flocculant properties, and environmental factors may influence flocculation efficiency, necessitating the selection of appropriate cellulose sources and modification methods for specific application scenarios. This review examines recent advancements in cellulose-based flocculants for microalgae flocculation, including their sources, preparation methods, flocculation mechanisms, modification techniques, and factors affecting efficiency. The potential value of cellulose-based flocculants and the key technical challenges they face are evaluated, with the aim of providing theoretical support for future research and advancing microalgae harvesting technologies using cellulose-based flocculants.