Adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface: a spectroscopic study.

The adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface at 30 degrees C in the dark was investigated. The color reduction was monitored by spectrophotometry at 503 nm. The FTIR and Raman spectra of the Direct Red 23 adsorption as a function of ZnO concentration were registered.