Asmamaw Taye*, Alemayehu Yifru, Solomon Mehretie, Negash Getachew, Shimelis Admassie
Water Hyacinth Leaf Protein Concentrate/Graphene Oxide/Chitosan/Polyvinyl Alcohol (WHLPC/GO/CS/PVA) composite was synthesized for the removal of Cr (VI) from wastewater. About 80% of the prepared composite material constitutes WHLPC which is extracted from water hyacinth plant leaf. The prepared material was characterized by FT-IR and XRD. The process variables such as pH, contact time, dosage, initial Cr (VI) concentration and temperature were optimized using a batch mode experiment. Kinetic studies were conducted using pseudo-first-order and pseudo-second-order models and it was observed that the chemosorptive pseudo-second-order model described the adsorption system in a better way, with a high value of R2. The highest adsorption capacity of 171.22 mg/g was achieved at pH 1.0 and equilibrium was achieved within 330 min. Langmuir and Freundlich isotherm models were analyzed using non linear fitting. It was found that the Freundlich model gives the best fit indicating multilayer adsorption of Cr (VI) on the WHLPC/GO/CS/PVA. The reuse efficiency of the synthesized material was also found to be greater than 65% for five consecutive cycles. Thermodynamic studies were conducted and results revealed that the adsorption was natural and endothermic.