Radiation-induced decoloration and sedimentation of colloidal disperse dyes in water

The aqueous solutions of disperse dyes can not be easily decolored and sedimented by γ radiation. The change of pH after irradiation into acidic conditions made sedimentation occur effectively. In oxygen-saturated solutions, absorption band, change of pH and total organic carbon decreased markedly, while in nitrogen-saturated solutions a smooth decrease was seen. Sedimentation was also induced by addition of various electrolytes. The mechanism of the sedimentation was also discussed.