Determination of the Dependence of Thermal Diffusivity with Moringa Concentration by Thermal Lens as a Sensitive Experimental Technique

The use of photothermal techniques has become of special importance due to their versatile application in the thermal characterization of materials. Therefore, the thermal lens technique in the mismatched dual-beam mode is an alternative, sensitive and non-evasive tool that was used in this research to determine the thermal diffusivity of Moringa oleifera. The dual arrangement of the thermal lens technique is based on the use of an Ar⁺Xe excitation laser (422 nm) and a He–Ne laser (632 nm) test laser. Moringa solutions were prepared by green synthesis with different concentrations ranging from 1.56 mg·mL⁻¹, 3.12 mg·mL⁻¹, 6.25 mg·mL⁻¹ to 12.50 mg·mL⁻¹. Different optical techniques (UV–vis, FTIR, XPS and EDS) were used to characterize the Moringa leaf powders. Results showed that the increase of thermal diffusivity could be related to the presence of functional groups and metallic elements in Moringa elemental composition. In this work, it was found that the thermal diffusivity of Moringa increases with increasing concentration. This study will be useful for application in heat transport and drug release.