Cobalt impregnated acid modified smectite in heterogeneous catalytic oxidation of azo dye using Oxone®

The starting clay from Bogovina (Serbia) rich in smectite was submitted to acid modificattion in order to improve textural properties. The acid modified sample was further impregnated with cobalt using 1 mol dm-3 solution of Co(NO3)2 followed by calcination at 450°C during 6 hours and used as heterogeneous catalyst. It was reported that sulfate radicals have high oxidattion potential and should be considered as efficient oxidants. The potassium peroxymonosulfate (Oxone® i.e. 2KHSO5∙KHSO4∙K2SO4) was used as radical source. Radicals were generated by presence of transition metal cation (Co2+) incorporated into smectite structure of the synthesized catalyst. The obtained catalyst was investigated in decolorization of azo dye Acid Orange 10 (AO10) in the presence of Oxone® at 30 and 50 °C. Kinetic of catalytic process was studied up to 4h. The AO10 concentration monitored using UV–Vis spectrophotometry, lmax=478 nm. The obtained results monfirmed that cobalt impregnated acid modified smectite can be successfully applied as catalyst in heterogenous Fenton-like reaction of azo dye and corresponding aromatic amines