Facile ultrasound-assisted synthesis of CuFe-Layered double hydroxides/g-C3N4 nanocomposite for alizarin red S sono-sorption

Abstract

BackgroundLayered double hydroxides (LDHs) have gained significant attention due to their exceptional performance and wide range of applications. In the present work, an ultrasound-assisted method was used to prepare novel CuFe-LDH/g-C3N4 (CFL/CN) nanocomposites. MethodsA sonicator tank was used as the source of ultrasonic waves to synthesize nano-sorbents called CFL/CN. The hydrothermal method was also used to determine the effect of ultrasonic waves on the morphology of CFL/CN nano-sorbents. In addition, the characterization of nano-sorbents prepared by hydrothermal and sonication methods was performed by techniques including XRD, FTIR, XPS, SEM, TEM, and BET. Also, the performance of the as-prepared nanomaterials was evaluated in removing alizarin red S (ARS) as a pollutant model by both adsorption and sono-sorption methods. Significant FindingsThe results showed that due to the presence of strong shock waves and the production of microbubbles in the reaction media, the thickness of diffusion layers was diminished for the sono-sorption method and this technique presented a promoted adsorption capacity, subsequently. The FESEM imaging confirmed that the sono-synthesis method led to a more well-dispersed shape and uniform morphology of nanoparticles. The results of XRD analysis showed that the sono-synthesized sample (Sono-CFL/CN) possessed a short-range ordered and high-crystalline structure in comparison to the hydrothermally-synthesized one (Hydro-CFL/CN). Also, TEM revealed the layered morphology of Sono-CFL/CN nanosorbents. The results of BET analysis also showed that sono-CFL/CN has a uniform morphology and improved BET surface area, pore volume, and pore size distribution. The sono-sorption efficiency of ARS was more effective on sono-CFL/CN samples (96.16%) in comparison to hydro-CFL/CN samples (53.4%). Moreover, the isothermal studies revealed that ARS adsorption onto the fabricated nanosorbents had good accordance with the Langmuir isotherm suggesting uniform surface energies. Also, kinetics investigations confirmed that the ARS adsorption data was well-matched with Ho's pseudo-second-order kinetics model. Finally, the high stability and activity of Sono-CFL/CN for ARS sono-sorption after 4 cycles showed that this material can be used as an efficient and economic nanosorbent to remove various organic dyes from the aqueous effluents.