Phosphotungstic acid supported on silica-coated LaCoO3: Synthesis, characterization and application as a novel and efficient adsorbent for the removal of organic pollutants

摘要

In this work, phosphotungstic acid (H3PW12O40, PW12) was supported successfully onto the surface of the silica-coated lanthanum cobaltite (LaCoO3@SiO2) and was characterized using different physicochemical techniques including FT-IR, XRD, SEM, TEM, EDX and AFM. Initially, single-phase perovskite-type LaCoO3 nanomaterial was synthesized via the decomposition of La[Co(CN)6]center dot 5H(2)O precursor and then was coated with a SiO2 shell by the Stober method. The as-prepared LaCoO3@SiO2 was used as a support for immobilizing phosphotungstic acid. This novel LaCoO3@SiO2/PW12 nanomaterial was used as an adsorbent for the removal of methylene blue (MB) and methyl orange (MO) organic dyes from aqueous solutions. The results reveal that the newly synthesized hybrid nanomaterial displays enhanced adsorption ability for cationic MB dye compared to bare LaCoO3 nanomaterial, probably due to enhanced electrostatic attraction interactions. The effects of initial pH, initial concentration and temperature of MB solution on adsorption ability of LaCoO3@SiO2/PW12 were also investigated. The hybrid nanomaterial was separated and reused without any observable change in its efficiency. Thus, it could be a promising green adsorbent for removing organic pollutants in water. (C) 2018 Elsevier Ltd. All rights reserved.