Physicochemical properties of nano fish bone prepared by wet media milling

Nano fish bone (NFB) was prepared using high-energy wet media milling. The characteristics of NFB including particle size distribution, morphology, elemental composition, ZETA potential, calcium ion concentration and chemical structure were investigated. The suitable operational parameters of milling were determined to be 0.5 mm diameter bead, agitation speed at 3000 rpm and a filling ratio of 85%. Under these conditions, fish bone particles were downsized to a nanometer scale within 2 h of milling and reached a minimum average size of 115 nm after 6 h. NFB particles showed polyhedron crystal morphology. Milling did not change the chemical structure of NFB. NFB particles were negatively charged and the absolute ZETA potential value significantly increased as the particle size decreased. Atomic proportion of calcium in the NFB particles decreased after milling and calcium ion concentration in the NFB suspension increased, indicating calcium was steadily released from the particles to the suspension during milling.