RESUMEN
MIL-53(Fe) was successfully prepared and deposited on the surface carboxylated polyester (PET) fiber by an optimized conventional solvothermal or industrialized high temperature pressure exhaustion (HTPE) process to develop a PET fiber supported MIL-53(Fe) photocatalyst (MIL-Fe@PET) for the degradation of polyvinyl alcohol (PVA) in water under light emitting diode (LED) visible irradiation. On the basis of several characterizations, MIL-Fe@PET was tested for the photocalytic ability and degradation mechanism. It was found that temperature elevation significantly enhanced the formation and deposition of MIL-53(Fe) with better photocatalytic activity. However, higher temperature than 130°C was not in favor of its photocatalytic activity. Increasing the number of surface carboxyl groups of the modified PET fiber could cause a liner improvement in MIL-53(Fe) loading content and photocatalytic ability. High visible irradiation intensity also dramatically increased photocatalytic ability and PVA degradation efficiency of MIL-Fe@PET. Na2S2O8 was used to replace H2O2 as electron acceptor for further promoting PVA degradation in this system. MIL-Fe@PET prepared by HTPE process showed higher MIL-53(Fe) loading content and slightly lower PVA degradation efficiency than that prepared by solvothermal process at the same conditions. These findings provided a practical strategy for the large-scale production of the supported MIL-53(Fe) as a photocatalyst in the future.
Asunto(s)
Colorantes , Alcohol Polivinílico , Peróxido de Hidrógeno , Luz , PoliésteresRESUMEN
Three aliphatic polycarboxylic acids (PCAs) including tartaric acid (TA), citric acid (CA) and 1,2,3,4-butanetetracarboxylic acid (BTCA) were used for the surface modification of waste cotton fiber by an industrialized pad-dry-cure process to introduce carboxyl groups, which then coordinated with Fe3+ ions to obtain three PCA modified cotton fiber Fe complexes. TA modified cotton fiber could easily react with Fe3+ ions to form its complex with high Fe content. Furthermore, TA modified cotton fiber Fe complex showed a better enhanced effect of activated Na2S2O8 to produce free oxygen radicals for the degradation of an azo dye, Reactive Red 195 than the other two complexes. Different critical Fe contents were found for three complexes to obtain the best enhanced effect.