Utilization of water hyacinth (Eichhornia crassipes) biomass as eco-friendly sorbent for petroleum oil spill cleanup

Abstract

This study focuses on the removal of spent engine oil (SEO) spill from the water surface using water hyacinth biomass (WHB)-based sorbents. The raw WHB was modified using extra virgin coconut oil (mainly consisting of lauric acid) to enhance the hydrophobicity and floating ability. With varying amounts of coconut oil and solvent, six diverse types of modified water hyacinth biomass (MWHB) were prepared. Among these MWHBs, an equal proportion of coconut oil and raw WHB with 10% methanol solution exhibited the highest removal of SEO reaching 96%. Various sorption kinetics and isotherm models were examined to understand the SEO sorption process on MWHB. The pseudo-second-order kinetics (R2 0.999) and both the Langmuir and Freundlich isotherm models (R2 0.992 and R2 0.999, respectively) were found to be the best-fitting models. These findings indicated a chemisorption mechanism involving the initial monolayer coverage of SEO molecules on the MWHB surface followed by the development of multilayers. The MWHB achieved a maximum sorption capacity of 4.75 g/g within 60 min. Furthermore, the reusability tests showed that MWHB maintained a sorption capacity of over 90% even after the third sorption–desorption cycle. HIGHLIGHTS Water hyacinth biomass was applied as an eco-friendly sorbent for the removal of simulated petroleum oil spills.; The hydrophobicity of biomass was enhanced by modifying it with extra virgin coconut oil.; The most suitable models describing the oil sorption were pseudo-second-order kinetics and Langmuir and Freundlich isotherm models.; The sorption capacity remained above 90%, even after the third sorption–desorption cycle.;

Keywords

• modified sorbent
• oil spills
• petroleum oil
• water hyacinth biomass