Preparation And Property Research Of Composite Catalyst-Metal-Organic Frameworks Loading With TiO₂

Nowadays, water pollution has become a serious factor limiting the development of our society, and more attentions are focused on water treatment technology. Photocatalysis of TiO2 has great potential in wastewater treatment field. TiO2 would exhibit excellent dispersion, large specific surface area and then enhanced photocatalytic activity when loaded on MOFs, which usually possess microporous structures. So in this paper, a series of MOF supported composite photocatalysts were fabricated and their photocatalysis (or adsorption) properties were investigated, which would have some reference value to wastewater treatment.Firstly, Co-MOFs were prepared according to literature and TiO2/Co-MOFs were obtained by the hydrolysis of tetrabutyl titanate in ethanol. The morphology, structure and chemical composition of TiO/Co-MOFs were characterized using IR, SEM, XRD and EDS and suitable experimental parameters were obtained. After being soaked in the solution of Na3PO4, TiO2/Co-MOFs showed excellent adsorption activity to methylene blue, attributed to the electrostatic interaction between phosphate anions and methylene blue and disordered structure of TiO2. Composite photocatlyst couldn’t be obtained by hydrothermal synthesis since Co-MOFs were thermosensitive and this part was just exploration for subsequent experiments.Secondly, Cu-MOFs were prepared according to literature and Cu-MOFs supported photocatalyst (TiO2/Cu-MOFs) was obtained by the hydrolysis of tetrabutyl titanate in ethanol. The TiO2 content in TiO2/Cu-MOFs could be changed by altering the amount of tetrabutyl titanate and methylene blue was chosen as organic pollutant to study the photocatalysis of TiO2/Cu-MOFs. We investigated the influence of amount of tetrabutyl titanate, hydrothermal temperature, hydrothermal time, morphology of Cu-MOFs and concentration of substrate to the photocatalytic activity of TiO2/Cu-MOFs and obtained suitable experimental parameters: 0.60mL of tetrabutyl titanate, hydrothermal treatment at 160℃ for 24h and 6ppm of substrate. Then, the photocatalytic activity of TiO2/Cu-MOFs and P25 was compared and TiO2/Cu-MOFs possessed higher activity than P25.Finally, MIL-101 was prepared according to literature and MIL-101 supported photocatalyst (TiO2/MIL-101) was obtained by the hydrolysis of tetrabutyl titanate in ethanol. The TiO2 content in TiO2/MIL-101 could be changed by altering the amount of tetrabutyl titanate. The adsorption property of TiO2/MIL-101 to various organic dyes and the photocatalysis to methyl orange were investigated in the experiment. With increased content of TiO2, adsorption of TiO2/MIL-101 to methyl orange and methylene blue decreased. With longer reaction time, the adsorption of TiO2/MIL-101 to methylene blue decreased, attributed to the dissolution of CO2 in air. The photocatalytic activity of TiO2/MIL-101 was lower than that of TiO2/Cu-MOFs, which may be the result of electrostatic adsorption affecting the electron transfer and higher substrste concentration.