Highly efficient adsorptive removal of phosphate using novel perovskite lanthanum ferrite/graphene oxide (LaFeO3-GO) hybrids from water

In current research, novel perovskite lanthanum ferrite/graphene oxide (LaFeO3-GO) hybrids were synthesized to evaluate its PO4-3 adsorption performance from water. Current study also compares viability of bimetallic LaFeO3-GO hybrids with lanthanum/graphene oxide (La-GO) and iron/graphene oxide (Fe-GO) composites under a series of systematically designed adsorption experiments. The superior adsorption capacity of (103.11 mg/g) LaFeO3-GO for PO4-3 was observed as compared to (83.67 mg/g) La-GO and (84.22 mg/g) Fe-GO, which was attributed to its highly amorphous characteristics, stable structure, and larger specific surface area. Moreover, the PO4-3 adsorption data of GO composites were well fitted with Pseudo second order and Freundlich model. Thermodynamic studies indicated that PO4-3 uptake using GO composites is spontaneous (negative value of Delta G) and endothermic (positive value of Delta H) in nature. The interfering ions investigations revealed the selective PO4-3 uptake by GO composites from water. Moreover, the reusability potential of LaFeO3-GO hybrids up to fifth cycle for PO4-3 uptake was observed to be 49.50 %. In accordance, the dominant role of charge neutralization, multilayered physio-chemisorption, and complexation reactions between bimetallic LaFeO3-GO and PO4-3 ions were evidenced, as revealed by XRD and FT-IR. In comparison, La-GO and Fe-GO also indicated involvement of ligand exchange and reduction pathways during PO4-3 adsorption process. Overall, these findings suggested that perovskite LaFeO3-GO hybrids had excellent adsorption capability, high selectivity, and stability towards PO4-3 ions, thus presenting sustainable solution in improving water quality.