Synthesis and characterization of heterogeneous catalyst EDTMPA-Cu-LDH and study of the mechanism of visible-light photocatalytic degradation of Rhodamine B

In this work, heterogeneous catalysts of Cu(II)-ethylenediamine tetramethylene phosphonic acid (Cu(II)-EDTMPA) complex intercalated layered double hydroxides (EDTMPA-Cu-LDH) was synthesized by co-precipitation method for visible-light photocatalytic degradation of Rhodamine B (RhB). The synthesized catalysts were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The results indicated that the EDTMPA-Cu-LDH showed a typical layered structure. After intercalation, layer spacing increased from 7.96 to 12.21 Å. The catalysts showed excellent catalytic activity for the degradation of RhB in visible light. The optimum conditions for RhB degradation were confirmed to be natural initial pH value 5.85, 10 mmol L –1 of RhB concentration, 7 mmol L –1 of H 2 O 2 concentration, and 0.3 g L –1 of catalyst dosage. The maximum degradation efficiency was 98.2% under the optimum conditions and excellent reusability and stability were obtained in the regeneration test. In the end, the reaction mechanism that might exist in the heterogeneous UV-Fenton system was proposed.