Photocatalytic degradation of crystal violet dye using sulphur-doped carbon quantum dots

The oil palm industry is the most advanced industry in Malaysia, which producing abundant biomass resources with limited applications. Empty fruit bunches (EFB) is one of the by-products of palm oil mill industry that containing lignin, which can potentially be used as raw material in the fabrication of sulphur-doped carbon quantum dots (SCQDs). SCQDs have been synthesised through a hydrothermal treatment using deionized water as a reaction medium. The as-fabricated SCQDs showed good fluorescent properties. The fluorescence SCQDs remained unchanged after several hours of UV-light exposure and over eight months of storage, indicating an outstanding stability and reactivity. The average particle size of SCQDs was found to be 2.9 nm. The potential application of SCQDs as photo-catalyst was explored in the photocatalytic activity through the degradation of crystal violet (CV) dye under UV-light irradiation (100 W). SCQDs showed a high-efficiency in the photo-degradation, which degraded about 99.7% of the CV dye within 200 min of UV-light irradiation. This research demonstrates a sustainable approach of producing a highly efficient photocatalyst towards the photo-degradation of organic dyes in wastewater treatment.