Graphene quantum dots functionalised with rhamnolipid produced from bioconversion of palm kernel oil by Pseudomonas stutzeri BK-AB12MT as a photocatalyst** Samuel Ivan, Fera Faridatul Habibah, Atthar Luqman Ivansyah, Rukman Hertadi
Bandung Institite of Technology
Abstract
Methylene blue (MB) is a common organic dye found in textile wastewater and can harm the environment. Rhamnolipid-functionalized graphene quantum dots (RL-GQDs) are a newly developed eco-friendly photocatalyst to degrade MB. This photocatalyst is synthesized from graphene quantum dots (GQDs) and rhamnolipid. GQDs are already promising visible-light photocatalysts to degrade organic dyes. However, GQDs are not promising photocatalysts due to their reusability and photocatalytic performance. In this work, we used rhamnolipid to modify GQDs^ structure and enhance their photocatalytic performance. The rhamnolipid used in this work was produced from bioconversion of palm kernel oil by mutated bacterial cells of Pseudomonas stutzeri BK-AB12MT. Meanwhile, GQDs were synthesized using the bottom-up method by pyrolysing citric acid. Transmission electron microscopy and Fourier-Transform Infrared spectroscopy were used to characterize these hybrid materials. These characterization techniques verified the formation of RL-GQDs. To prove the photocatalytic performance of RL-GQDs, we investigated the photocatalytic activity under visible light compared to some common photocatalysts, such as zinc oxide and titanium dioxide. Our findings showed that RL-GQDs could be applied as an eco-friendly photocatalyst to replace TiO2 with a degradation efficiency of 59 (percent) aproximaly 3 (percent) under visible light irradiation, higher than TiO2.
Keywords: Methyleb Blue Degradation, Photocqtalyst, Rhamnolipid Functionalized Quantum Dots
