Influence of Manganese Ions on Physical and Optical Property of Glass made from Sugarcane Leaf Ash from Biomass Power Plants

Abstract

This research investigates the influence of manganese ions on the physical and optical properties of glass synthesized from sugarcane leaf ash (SLA) obtained from biomass power plants. The SLA was utilized as the primary raw material to replace pure chemicals, specifically silica and calcium oxide. Chemical composition analysis via the EDXRF technique revealed that SLA contains SiO2 and CaO as major constituents at 66.77% and 17.26% by weight, respectively. Glass samples were prepared using the melt-quenching method at 1,200°C, followed by an annealing process at 500°C. Experimental results indicated that increasing the concentration of manganese dioxide (MnO2) from 0.0 to 0.5 mol% led to a decrease in glass density from 2.8756 to 2.8501 g/cm3, while the molar volume increased from 22.2437 to 22.4892 cm3/mol. This phenomenon reflects the expansion of the glass network due to the formation of non-bridging oxygen (NBO). Regarding optical properties, the refractive index showed a declining trend from 1.5703 to 1.5651, consistent with the density variations according to the Lorentz-Lorenz theory. The optical absorption spectra exhibited broad absorption bands centered around 500 nm, resulting from the 5Eg  5T2g electronic transition of Mn3+ ions. This led to a significant physical color transformation from the brownish-yellow observed in the control group to an intensified brownish-yellow hue. These findings align with the CIE L*a*b* color analysis, which showed a decrease in brightness (L*) and an increase in the b* value (yellowness) as the dopant concentration increased. In conclusion, sugarcane leaf ash demonstrates high potential as a sustainable alternative material for developing functional glass with unique optical properties and environmental benefits.