Preparation of titania-containing photocatalysts from metallurgical slag waste and photodegradation of 2,4-dichlorophenol

A low cost, high performance titania-containing metallurgical slag photocatalysts (TCMSPx, x = H2SO4, HNO3, HCl) were prepared using a hydrothermal method. The prepared TCMSPx were characterized in terms of visual, physical and chemical properties. The photocatalytic activity of the TCMSPx was evaluated via the photodegradation of 2,4-dichlorophenol (2,4-D) in aqueous solution. The results showed that the characteristics and photocatalytic activity of TCMSPx were strongly affected by acidic solutions used during the acidolysis. TCMSPH2SO4TCMSPH2SO4 exhibited better characteristics and higher photocatalytic activity than TCMSPHNO3TCMSPHNO3 and TCMSPHCl. OH radicals from TCMSPH2SO4TCMSPH2SO4 were produced under UV, visible and solar light irradiation. The degree of photodegradation of 2,4-D by TCMSPH2SO4TCMSPH2SO4 was 80.1%, 50.0% and 61.5% under UV, visible and solar light irradiation respectively. In addition, the removal of chlorine functional group on the 2,4-D benzene ring and the production of intermediates during 2,4-D photodegradation were monitored using ion chromatography, UV–vis spectra and high performance liquid chromatography of 2,4-D before and after photodegradation.