Supplementary material to 'Fenton-like oxidative degradation of Orange G dye and binary dye mixtures using Oxone® activated with cobalt-doped alumina catalysts'

Two texturally and structurally different Co-doped aluminas were obtained by using the sol-gel method followed by calcination at temperatures of 1000 °C and 1100 °C. The obtained materials were tested as catalysts in anionic textile dye Orange G (OG) degradation using Oxone® as a precursor of sulfate anion radicals, the main reactive oxygen species. Effects of temperature and initial pH on degradation efficiency was investigated. The increase in temperature accelerated the reaction rate and the maximal degradation efficiency was obtained at 60 °C. Different kinetic models were applied and pseudo-first order rate was found to be the most appropriate. Both catalysts showed the optimal performance in the pH range around neutral. Coexisting cations (Ca2+, Mg2+, K+ and Na+) enhanced the OG degra­dation rate, as well as anions: Clˉ and H2PO4ˉ, while NO3ˉ, SO42ˉand HCO3ˉ inhibited the degradation. The catalysts were also proved effective in degradation of the other investi­gated dyes: Methylene blue, Basic blue 41, and Remazol brilliant blue R. Finally, simulta­neous degradation of OG in binary dye mixtures was investigated showing that the synthesized catalysts can be also used in simultaneous processes of dye degradation. However, differences in structural and textural properties of the two catalysts affected their catalytic performance.
Dva kobaltom dopirana katalizatora na bazi aluminijum oksida, sa ra zličitim teksturalnim i strukturnim karakteristikama, dobijena su sol-gel postupkom sinteze, nakon koje su uzorci žareni na tempreturi od 1000 °C odnosno 1100 °C. Dobijeni materijali su ispitani kao katalizatori u procesu degradacije anjonske tekstilne boje Orange G (OG) uz korišćenje Oksona kao prekursora sulfatnih anjon radikala, koji su glavna oksidativna vrsta. Ispitan je uticaj temperature i početnog pH na efikasnost degradacije, i uočeno je da porast temperature povećava brzinu reakcije. Maksimalna efikasnost degradacijeje dobijena na 60 °C. Primenjeni su različiti kinetički modeli i pokazalo se da kinetički model pseudo-prvog reda najbolje opisuje kinetiku ispitanog procesa. Takođe je za oba katalizatora utvrđeno da je optimalna vrednost pH za ispitivanu reakciju u oblasti blizu neutralne. Koegzistirajući katjoni (Ca2+, Mg2+, K+ and Na+) i anjoni Clˉ and H2PO4ˉ su ubrzavali degradaciju OG, dok su je anjoni NO3ˉ, SO4 2ˉ i HCO3ˉ usporavali. Katalizatori su se pokazali efikasnii u degradaciji boja: metilensko plavo, osnovno plavo 41 i boje “Remazol brilliant blue”, kao i u degradaciji boja u binarnim smešama. Ipak, razlike u strukturnim i teksturalnim svojstvima su uticale na razlike u katalitičkoj efikasnosti ova dva katalizatora.