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TiO 2 photocatalyst beads were synthesised using the circulating fluidised bed-chemical vapour deposition (CFB-CVD) method. Their photocatalytic activity was compared with the TiO 2 photocatalyst balls synthesised using the conventional CVD (C-CVD) method. The TiO 2 film synthesized by CFB-CVD showed (110) oriented anatase crystal structure. Compared to the film synthesised by C-CVD, the CFB-CVD synthesised film had much less dense crystal structure owing to TiO 2 powders precipitated during the film growth. When the CFB-CVD synthesised TiO 2 beads were used in the photocatalytic decomposition of RhB in a fluidised bed reactor, the decomposition rate increased with increasing UV intensity and circulating flowrate and with decreasing initial RhB concentration. One important shortcoming of the TiO 2 photocatalyst beads synthesised by CFB-CVD turned out to be that the photocatalytic activity was decreased significantly by repeated reuse, calling for further investigation to improve the durability.

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In this study, zero-valent iron (ZVI) was produced using iron oxide that is a by-product of a pickling line at a steel works. The reaction activity of the produced ZVI was evaluated through a series of decomposition experiments of Orange II aqueous solution. The size of ZVI particles increased with reduction temperature due to coalescence. Correspondingly, the specific surface area of ZVI decreased with increasing reduction temperature. The decomposition efficiency of synthesized ZVI particles was higher at a lower pH. In particular, no significant decomposition reaction was observed at pH of 4 and higher. The rate of the ZVI-assisted decomposition of Orange II was increased by addition of H2O2 at pH of 3, whereas it was reduced by addition of H2O2 at a higher pH of 6. Nevertheless, simultaneous use of ZVI, UV and H2O2 led to a considerable increase in the decomposition rate even at a high pH condition (pH = 6).