Cellulose is a valuable natural resource for the development of innovative biomaterials with diverse applications, driving the growing demand for advancing sustainable and efficient methods for its modification.[1] Mechanochemistry has emerged as a powerful tool for green synthesis, allowing to eliminate or significantly reduce amounts of solvent usage,[2] which is particularly advantageous for modifying inherently insoluble cellulosic materials. Here, we present a solid-state approach for the efficient cationization of low processed cotton fibers (Whatman 1 filter paper, FP) via etherification reaction. Our results show that cationic cellulose material can be prepared in more efficient and sustainable way, while reducing waste generation. Moreover, the material demonstrated a strong ability for binding viruses,[3] thus offering promising applications in biotechnology and purification processes.