Production of a Composite Based on Alumina Nanofibers and Detonation Nanodiamonds for Creating Phenol Indication Systems

Abstract

A composite of alumina nanofibers (ANF) and modified detonation nanodiamonds (MDND) was produced by mixing aqueous suspensions of the components in a weight ratio of 5 : 1 with subsequent incubation of the mixture for 15 min at 32°C. It was assumed that the formation of the composite is ensured by the difference of the zeta potentials of the components, which is negative for MDND and positive for ANF. Vacuum filtration of the mixture through a fluoroplastic filter (pore diameter 0.6 μm) formed disks 40 mm in diameter, which were then heat-treated at 300°C to impart structural stability to the composite. Scanning electron microscopy detected that the obtained composite has a network structure, in which MDND particles are distributed over the surface of ANF. It was determined that the MDND particles incorporated in the composite catalyze the phenol–4-aminoantipyrine–H₂O₂ oxidative azo coupling reaction to form a colored product (quinoneimine). The applicability of the composite to repeated phenol detection in aqueous samples was demonstrated.