PHOTODECOMPOSITION OF HEXACYANOFERRATE(II I) ION IN ALKALINE-SOLUTIONIN THE PRESENCE OF OZONE AND EFFECT OF CU TIO2 COMPOSITE POWDERS ADDITION/

The photochemical decomposition behavior of hexacyanoferrate(III) ion ([Fe(CN)(6)](3-)) in alkaline solution using ultraviolet light in nitr ogen atmosphere was reported in a previous paper. In this paper, Cu/Ti O2(anatase) composite powders were added to promote the photochemical decomposition of [Fe(CN)(6)](3-), and ozone(O-3) was used as oxidizing agent of CN-, based on the reports of titanium(N) oxide(TiO2) as the photocatalyst of [Fe(CN)(6)](3-) to aquapentacyanoferrate(III) ion([Fe (CN)(5)(OH2)](3-)) and copper(Cu) as the oxidizing catalyst of CN- to OCN- in ozone atmosphere. Effect of Cu/TiO2 composite powders addition to [Fe(CN)(6)](3-), CN- and OCN- solutions in the flow stream of O-3 under irradiation was studied by means of VIS-UV spectroscopy, ion chr omatograpy and chemical analysis. As the results, it was found that th e reduction-decomposition of [Fe(CN)(6)](3-) to [Fe(CN)(5)(OH2)](3)- a nd CN- was accelerated due to suppression of the reaction of [Fe(CN)(6 )](3-) to hexacyanoferrate(II) ion ([Fe(CN)(6)](4-)), by the addition of Cu/TiO2 in O-3 atmosphere under irradiation. However, under the sam e condition in dark, [Fe(CN)(6)](3-) did not degrade even in the flow stream of O-3 The oxidation reaction of CN- to OCN- by the addition of Cu/TiO2 in O-3 under irradiation was found to be promoted much more t han under the same condition in the absence of Cu/TiO2. In addition, t he decomposition of OCN- to CO2 and N-2 in O-3 Seemed to occur simulta nously with the hydrolysis of OCN- in acidic solution.