Terminalia catappa leaf extract as a bio-reducing agent to synthesize Cu2O nanoparticles for methylene blue photodegradation

Abstract

The large tree species Terminalia catappa is a member of the Combretaceae family and is mainly found in tropical climates. They are commonly cultivated for shade because they have huge, dense foliage. Numerous polyphenols, including flavonoids, tannins, saponins, and phytosterols, are present in the leaves. In this study, the green chemical method was used to extract polyphenols from dried green almond leaves. They were employed in the synthesis of Cu2O nanoparticles as a reducing agent. FTIR and UV–Vis were used to describe the leaf extract of Terminalia catappa after the chlorophyll was removed. Copper salt was used to create Cu2O nanoparticles via a reduction process. The extract's potential for photocatalytic dye degradation has also been explored. The obtained Cu2O had a spherical shape with dimensions of 50–100 nm, and its band gap energy reached 1.945 eV to remove methylene blue from aqueous media under visible light irradiation conditions. At an initial MB concentration of 10 ppm, the decomposition efficiency reached 71.99% after only 2 h of exposure to simulated sunlight. The decomposition process occurred according to a pseudo-first-order kinetic model with a rate constant of 0.0084 min−1.