Photocatalytic decolorization of methyl violet dye using Rhamnolipid biosurfactant modified iron oxide nanoparticles for wastewater treatment

Abstract

Wastewater discharged by some industries under uncontrolled and unsuitable conditions is leading to significant environmental concern. Dyes are one of the major constituents in wastewater. Industrial dyes are stable, toxic and also considered potentially carcinogenic. Their release into the environment can lead to serious environmental and health problems. Hence, it is important to treat dye wastewater before it gets discharged in outer environment. In this study, Iron oxide nanoparticles (IONPs) were synthesized by co-precipitation method. The iron oxide nanoparticles were then surface functionalized by the Glycolipid biosurfactant, Rhamnolipid (RL) which was produced by Pseudomonas aeruginosa ATCC 9027. The surface functionalization of iron oxide nanoparticles by biologically obtained Rhamnolipid reduces toxicity and at the same time makes the material biodegradable and highly selective due to presence of some reactive functional groups on the surface. IONPs and Rhamnolipid functionalized iron oxide nanoparticles (RL@IONPs) were characterized by UV–VIS spectroscopy, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Photo catalytic activity of IONPs and RL@IONPs was studied for methyl violet dye. In addition to this, sodium dodecyl sulphate (SDS) was used as an efficient adsorbent and the dye removal efficiency with SDS as a binding agent was found to be 92.72%. The high adsorption and dye removal efficiency of RL@IONPs establishes its potential in detoxifying wastewater streams from hazardous dyes.