Impact of metal ions concentration on effects of fluorescent whitening agents for cellulose substrates

Abstract

The influence of metal ions, iron and copper, in the concentration range of 1, 5, 10 and 30 ppm added to the solution of fluorescent whitening agent (FWA) in concentrations of 0.08, 0.12 and 0.25% for processing cellulose substrates at room temperature was investigated. The properties of cellulose substrates were monitored through optical and protective effects, fluorescence spectra, degree of whiteness and UPF (Ultraviolet Protection Factor) values, were analysed. The analysed optical and protective phenomena differ for treated cellulose substrates, fabric and filter paper. FWAs increase the whiteness and UV protection of the material. It was found that the metal ion added in different concentrations affects the reduction and quenching of fluorescence and the reduction of the whiteness of cellulose substrates. The influence of metal ions on UPF depends on the substrate, the type and concentration of the metal ion, and the concentration of the fluorescent whitening agent to which they were added.