Zeolite imidazolate framework-11 for efficient removal of Bromocresol Green in aqueous solution, isotherm kinetics, and thermodynamic studies

Abstract

* Corresponding author.1944-3994/1944-3986 © 2021 Desalination Publications. All rights reserved.Desalination and Water Treatment www.deswater.comdoi: 10.5004/dwt.2021.27183224 (2021) 407–420JuneZeolite imidazolate framework-11 for efficient removal of Bromocresol Green in aqueous solution, isotherm kinetics, and thermodynamic studiesRachid Lamaria,*, Bénamar Benotmanea, Samira MezalibaURMPE, M’Hamed Bougara University, Boumerdes 35000, Algeria, Tel. +213 662044327/213 659010318; emails: r.lamari@univ-boumerdes.dz (R. Lamari), b.benotmane@univ-boumerdes.dz (B. Benotmane) bFaculty of Sciences, Chemical Department, M‘Hamed Bougara University, Boumerdes 35000, Algeria, Tel. +213 553726873; email: s.mezali@univ-boumerdes.dzReceived 16 May 2020; Accepted 19 February 2021abstractIn this study, zeolitic imidazolate framework (ZIF-11) type was synthesized by stirring method and used for the removal of Bromocresol Green (BCG) from aqueous solutions. For this purpose, the ZIF-11 particles were analysed by X-ray diffraction, scanning electron microscope, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. In batch experiments, the effective BCG adsorption parameters onto ZIF-11 particles were exam-ined. Based on the characterization results, the synthesized ZIF-11 showed a highly porous, irreg-ular, and inhomogeneous shapes and crystals with varying sizes as well as high thermal stability. The adsorption results indicated that the highest BCG removal (89%) was obtained when the solu-tion pH, the stirring speed, the contact time, and the temperature were adjusted to 6.8, 400rpm,30min, and 298K, respectively. The adsorption data fitted well to Langmuir and Temkin mod-els with maximum adsorption capacity of 150mg/g.The adsorption kinetics was compatible with the pseudo-second-order and the intraparticle diffusion models. Indeed, BCG molecules instanta-neously adsorbed on the external surface of ZIF-11 particles and gradually diffused within theirs pores. The negative value of free energy change and positive values of enthalpy and entropy changes showed the feasibility, randomness, and endothermicity of the BCG adsorption process, which was found to be physicochemical based