Redox-driven green synthesis of silver nanoparticle/cellulose nanofiber composites using high-pressure wet-type jet-milling

A sustainable method for efficiently producing and depositing silver nanoparticles (AgNPs) onto cellulose nanofibers (CNFs) was developed in this study by harnessing high-pressure wet-type jet milling-induced redox reactions.An aqueous solution of silver nitrate was mixed with a CNF suspension and subsequently subjected to 0-4 jet-milling passes at a discharge pressure of 200 MPa.Additionally, the influence of the pipe fitting material on the formation of nanoparticles (NPs) was evaluated by using either 304 stainless steel (SUS304) or brass pipe fittings between the feed tank and the collision chamber.The X-ray diffraction pattern of the sample prepared using brass fittings and subjected to one jet-milling pass exhibited distinct peaks corresponding to metallic silver, confirming the presence of AgNPs, in addition to those from cellulose crystallites.In contrast, the sample prepared using SUS304 fittings exhibited only peaks corresponding to cellulose crystallites, with no detectable peaks attributable to metallic silver.Transmission electron microscopy revealed that the CNF surface of the sample processed with brass fittings were uniformly and densely covered with spherical AgNPs (diameters