Photocatalytic Removal of Copper and Selenium from Waste water under Visible Light

Abstract

Zirconia and silica mixed titanium oxides were synthe-sized by modified sol-gel method in presence of a surf-actant (CETAB). Materials were characterized by surface area, XRD, SEM and UV-Vis spectroscopy. Materials are found to be in uniform size and mostly spherical when synthesized in presence of CETAB. Effect of sum factant concentration on the particle size, shape and the catalytic activity is also evaluated. Calcination temp-erature plays an important role on the phase stability and catalytic activity of the materials. It is well observed that without any hole scavenger the efficiency of photocatalytic metal removal is quite low for both the metal ions within 30minuites of reaction. However, addition of hole scavenger increases the activity many folds and hence complete removal of Se and Cu was possible in 30 minutes of reaction. Among all the organic hole scavengers used, sodium formate is found to be the most active one for selenium whereas for copper EDTA is the most suitable one. Reaction pH also plays important role in the efficiency of the metal removal. Above all synth-esized materials are found to be efficient catalyst for visible light reaction. The same catalyst is found to be reusable at least for 5-6 times with 4-5% decrease in the activity.