Study On The Photocatalysis Of Degradation Of Parts Of Reactive Dyes With Composite Catalyse

The photocatalytic degradation of two reactive dyes, reactive orange KGN and reactive red M3B, have been investigated with phospho-tungstic acid(H₃PO₄·12WO₃·XH₂O, abbreviated as PW₁₂), silicotungstic acid (SiO₂·12WO₃·26H₂O, abbreviated as SiW₁₂ ), titanium dioxide(TiO₂), hydrogen peroxide(H₂O₂) and composite systems in water. The effect factors such as pH value, catalyse concentration, gross and proportion of the catalyst were studied in the paper by the method of orthogonal experiment. DC, DTOC and the change of pH value and conductivity were studied too.The main results of experiments with each catalyst were as follows: The optimum pH value of KGN photocatalysed by PW₁₂, SiW₁₂, TiO₂ and H₂O₂ were 2, 3.5, 3.5 and 3 respectively; The optimium concentrations of the catalyst were 0.6, 0.1, 0.5g/L and 43.14mmol/L respectively. The optimium pH value of M3B photocatalyzed by PW₁₂ , SiW₁₂, TiO₂ and H₂O₂ were 2, 5.2, 10 and 3 respectively; The optimium concentrations of the catalyst were 0.1, 0.1, 0.7g/L and 43.14mmol/L respectively.The main experimental results with composite catalyst were as follows: 1.When KGN and M3B were photocatalytically degraded with composite catalyst of PW₁₂/SiW₁₂, there were no synergistic effect on DC, but there were that on DTOC; 2. When KGN were photocatalytically degraded with composite catalyst of PW₁₂/TiO₂, there were no synergistic effect on DC and DTOC but there were synergistic effect on DC and DTOC in M3B system; 3. When with composite catalyst of TiO₂/SiW₁₂ and H₂O₂/SiW₁₂, there were no synergistic effect on DC and DTOC. 4. When with composite catalyst of PW₁₂/H₂O₂ and TiO₂/H₂O₂, the synergistic effect on DC decreased with increasing of hydrogen peroxide concentration. There were no synergistic effect on DTOC expect TiO₂/H₂O₂ in KGN system.The photocatalytic degradation reaction of KGN and M3B with all kinds of catalysts were first-order. The photocatalytic degradation...