LaMnO3/ZnO/NGP composite: Synthesis, characterization and its application for wastewater treatment

Abstract

A series of LaMnO3/ZnO/NGP samples was successfully synthesized using co-precipitation method in 3 weight percentage of nanographene platelets (NGP) on LaMnO3/ZnO (3, 5, 10 wt.%). The structure of the sample was studied by X-ray diffraction (XRD) and Raman spectroscopy. The morphology and element structure of the sample was studied by Transmission electron microscopy (TEM) and Energy dispersive x-ray (EDX) spectroscopy, respectively. The thermal stability of the sample was characterized by thermogravimetric analysis (TGA). The XRD pattern confirmed the following structures: orthorhombic for LaMnO3 nanoparticles, hexagonal wurtzite for ZnO nanoparticles and graphitic like for NGP. The samples were tested for methylene blue (MB) removal and they show successful results in wastewater treatment through the adsorption test. The removal of MB was investigated by changing experimental variables such as the LaMnO3/ZnO/NGP dosage, the weight percentage of NGP on LaMnO3/ZnO and initial MB concentration. The experimental analysis of adsorption kinetics was best fit using pseudo second-order and Langmuir kinetic model. The increasing weight ratio of NGP shows higher adsorption of MB. Among the three different synthesized weight ratio of NGP in LaMnO3/ZnO (3, 5, 10 wt.%), 10 wt.% of NGP on LaMnO3/ZnO shows the maximum adsorption capacity than others.