Photocatalytic Degradation of Malachite Green by Titanium Dioxide/Covalent Organic Framework Composite: Characterization, Performance and Mechanism

In this paper, a titanium dioxide/covalent organic framework (TiO₂/COF) composite was prepared and its photocatalytic removal of dye was investigated. Using tetrabutyl titanate as a titanium source, TiO₂ nanomaterial was prepared by sol-gel method. In the presence of TiO₂, TiO₂/COF core-shell composite was prepared by solvothermal synthesis using melamine and 1,4-phthalaldehyde as ligands. The prepared materials are characterized by SEM, TEM, XPS, XRD, TG, FTIR, BET, EPR, PL, and UV-Vis-DRS techniques. Using malachite green (MG) as a model of dye wastewater, the photocatalytic degradation performance of TiO₂/COF composites was investigated under the irradiation of ultraviolet light. The results show that the modification of COF significantly improves the photocatalytic efficiency of TiO₂, the degradation rate increases from 69.77 % to 93.64 %, and the reaction rate constant of the first-order kinetic equation is increased from 0.0078 min⁻¹ to 0.0192 min⁻¹. Based on the free radical capture experiment, the photocatalytic degradation mechanism of TiO₂/COF was discussed, and the feasibility of its photocatalytic degradation of malachite green was theoretically clarified. Accordingly, a simple and practical method for photocatalytic degradation of malachite green was constructed, which has potential application value in the degradation of dye wastewater.

Abstract

In this paper, a titanium dioxide/covalent organic framework (TiO₂/COF) composite was prepared and its photocatalytic removal of dye was investigated. Using tetrabutyl titanate as a titanium source, TiO₂ nanomaterial was prepared by sol-gel method. In the presence of TiO₂, TiO₂/COF core-shell composite was prepared by solvothermal synthesis using melamine and 1,4-phthalaldehyde as ligands. The prepared materials are characterized by SEM, TEM, XPS, XRD, TG, FTIR, BET, EPR, PL, and UV-Vis-DRS techniques. Using malachite green as a model of dye wastewater, the photocatalytic degradation performance of TiO₂/COF composites was investigated under the irradiation of ultraviolet light. The results show that the modification of COF significantly improves the photocatalytic efficiency of TiO₂, the degradation rate increases from 69.77 % to 93.64 %, and the reaction rate constant of the first-order kinetic equation is increased from 0.0078 min⁻¹ to 0.0192 min⁻¹. Based on the free radical capture experiment, the photocatalytic degradation mechanism of TiO₂/COF was discussed, and the feasibility of its photocatalytic degradation of malachite green was theoretically clarified. Accordingly, a simple and practical method for photocatalytic degradation of malachite green was constructed, which has potential application value in the degradation of dye wastewater.

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