High adsorption capacity of two Zn-based metal-organic frameworks by ultrasound assisted synthesis

Micro- and nano-rods and plates of two 3D, porous Zn(II)-based metal-organic frameworks [Zn(oba) (4-bpdh)(0.5)](n)(DMF)(1.5) (TMU-5) and [Zn(oba)(4-bpmb)(0.5)] (DMF)(1.5) (TMU-6) were prepared by sono-chemical process and characterized by scanning electron microscopy, X-ray powder diffraction and IR spectroscopy. These MOFs were synthesized using a non-linear dicarboxylate (H(2)oba = 4, 4-oxybisbenzoic acid) and two linear N-donor (4-bpdh = 2,5-bis(4-pyridy1)-3,4-diaza-2,4-hexadiene and 4-bpmb = N-1,N-4-bis((pyridin-4-yl)methylene)benzene-1,4-diamine) ligands by ultrasonic irradiation. Sonication time and concentration of initial reagents influencing size and morphology of nano-structured MOFs, were also studied. Calcination of TMU-5 and TMU-6 at 550 degrees C under air atmosphere yields ZnO nanoparticles. TMU-5 and TMU-6 exhibited maximum percent adsorption of 96.2% and 92.8% of 100 ppm rhodamine B dye, respectively, which obeys first order reaction kinetics. (C) 2016 Elsevier B.V. All rights reserved.