Microwave‐Assisted Synthesis of HKUST‐1 and Functionalized HKUST‐1‐@H₃PW₁₂O₄₀: Selective Adsorption of Heavy Metal Ions in Water Analyzed with Synchrotron Radiation

Abstract

A simple, rapid and efficient synthesis of the metal-organic framework (MOF) HKUST-1 [Cu3(1,3,5-benzene-tri-carboxilic-acid)2] by microwave irradiation is described, which afforded a homogeneous and highly selective material. The unusually short time to complete the synthesis by microwave irradiation is mainly attributable to rapid nucleation rather than to crystal growth rate. Using this method, HKUST-1-MW (MW=microwave) could be prepared within 20 min, whereas by hydrothermal synthesis, involving conventional heating, the preparation time is 8 h. Work efficiency was improved by the good performance of the obtained HKUST-1-MW which exhibited good selective adsorption of heavy metal ions, as well as a remarkably high adsorption affinity and adsorption capacity, but no adsorption of Hg(2+) under the same experimental conditions. Of particular importance is the preservation of the structure after metal-ion adsorption, which remained virtually intact, with only a few changes in X-ray diffraction intensity and a moderate decline in surface area. Synthesis of the polyoxometalate-containing HKUST-1-MW@H3PW12O40 afforded a MOF with enhanced stability in water, due to the introduced Keggin-type phosphotungstate, which systematically occluded in the cavities constituting the walls between the mesopores. Different Cu/W ratios were investigated according to the extrusion rate of cooper ions concentration, without significant structural changes after adsorption. The MOFs obtained feature particle sizes between 10-20 μm and their structures were determined using synchrotron-based X-ray diffraction. The results of this study can be considered important for potentially wider future applications of MOFs, especially to attend environmental issues.

Recent Progress in Metal–Organic Frameworks and Their Derived Nanostructures for Energy and Environmental Applications

“…For example,p ristine MOF-5, am ember of the zinc-based MOF family,w as reported as efficient absorbents for the removal of copperi ons from aqueouss ystems. [140] To furtheri mprove the adsorption capacity and selectivity of heavy-metal ions, various functionalization methodsh ave been developed to modify pristine MOFs with desirable functional groups for the selective removal of heavy-metal ions from aqueous systems. More recently,Z hang et al reported that pristine zeolitic imidazolate framework( ZIF-8) could be directly used as apromising absorbent for the removal of Cu 2 + with high adsorption capacity and removal efficiency for Cu 2 + in aqueous systems.…”

Remediation of pharmaceutical contaminated water by use of magnetic functionalized metal organic framework. Physicochemical study of doxycycline adsorption

“…FTIR analysis of the synthesized MOF showed that its spectrum was similar to that of the samples prepared by Wei Li (Zou et al . ). The adsorption bands of (Arc–H) correspond to aromatic groups and the –OH bending vibrations of the water molecules observed at 3000–3500 cm −1 (Supporting Information Fig.…”

“…where C i and C f are initial and final concentrations (mg/L), respectively, m is the amount of the adsorbent (g) and V is the volume of the solution (L). The effect of temperature on the adsorption capacity was evaluated at 298, 313, 328 and 343 K. The kinetic of adsorption process was studied between 5 and 120 min at 298 K. (Zou et al 2013). The adsorption bands of (Arc-H) correspond to aromatic groups and the -OH bending vibrations of the water molecules observed at 3000-3500 cm 21 (Supporting Information Fig.…”

Tuning the crystal size and morphology of the substituted imidazole material, SIM-1

“…In order to minimize the variables, optimize the yield, and control particle size, topology, and morphology, alternative synthesis methods have been investigated. These include in situ [12] and ex situ reaction methods [13,14], microwave assisted synthesis [15][16][17], electrochemical [18], mechanochemical [19], sonochemical [20], and ligand exchange [21,22].…”