Synthesis, characterization of Mg-Al-CO3 hydrotalcites modified by Cu2+ ions using as photocatalyst for degradation of methylene blue in water

Abstract

The CuMgAl hydrotalcite materials were synthesized by co-precipitation method using nitrate salts of Mg²⁺, Al³⁺, Cu²⁺ and Na₂CO₃ (Merck), at pH = 9.5, aged in a teflon flask at 100 ^oC for 24 hours. The synthesized materials were characterized by the following methods: XRD diagram, TEM image, EDS spectrum, the adsorption/desorption isotherm N₂ (BET), UV-Vis DRS spectroscopy. The characterization results showed that the 8 synthesized samples have a double layered structure of hydrotalcite, the average particle sizes in the range of 15.09-21.20 nm and the absorption margin shifts strongly to the visible light region. The conversion of methylene blue (MB) increases when the ratio molars of ion Cu²⁺ in the samples arrange in 0 to 3.5, and set of the CuMgAl-2.5, CuMgAl-3.0 and Cu-MgAl-3.5 materials showed that they are able to degradate MB very well under visible light. The conversion of MB 30 ppm can reach 94 % after 90 min on CuMgAl-3.0 sample using irradiation of LED lamp 30 W light. The catalytic activity of the materials depends on the amount of Cu²⁺ in the sample, the concentration of H₂O₂, MB and the pH values of the medium.