Synthesis and characterization of silica nanoparticles from solar panel glass cullet

The rapid growth of solar energy as a renewable resource has led to a significant increase in discarded solar panels. Recycling their glass components, especially fine cullet fragments, remains a major challenge due to impurity levels and processing limitations. This study proposes a sustainable approach to recycle solar panel glass cullet into high-purity silica nanoparticles using alkali fusion followed by acid precipitation. Process conditions including cullet to NaOH ratio, fusion temperature, and surfactant addition were optimized. The highest silica yield of 60.26% was achieved at a 1:1.4 cullet to NaOH ratio and 500℃. Polyethylene glycol (PEG 1000) was used as a surfactant to reduce agglomeration and enhancing surface characteristics. BET analysis showed that PEG addition increased the specific surface area to 372.34 m2∙g‒1 and formed a compact mesoporous structure with an average pore size of 8.91 nm. In comparison, samples without PEG exhibited a larger pore size of 12.36 nm and a lower surface area of 360.24 m2∙g‒1. EDX confirmed the high purity of the synthesized silica, with 95.12% SiO2. These findings demonstrate a practical and environmentally beneficial method to convert problematic solar panel waste into valuable nanomaterials, supporting sustainable resource recovery and circular economy goals.