Carbon composite membrane derived from MIL-125-NH2 MOF for the enhanced extraction of emerging pollutants.

Porous carbon derived from amine-functionalized MIL-125 metal-organic framework (C-MIL-125-NH2) was prepared by carbonization at high temperature under inert atmosphere, and used for adsorption of bisphenol A (BPA) and 4-tert-butylphenol (4-tBP). The obtained carbon showed bimodal porosity and fast extraction of both pollutants in batch conditions following a pseudo-second-order model. The adsorption mechanism was studied by the measurement of zeta potential, and the results suggested that π-π stacking interactions between the carbon material and the phenol molecules probably are the main sorption mechanism. The prepared C-MIL-125-NH2 was incorporated into mechanically stable membranes for flow-through solid-phase extraction of studied phenols prior to HPLC analysis. The hybrid material showed excellent permeance to flow, easy regeneration and good performance for the simultaneous enrichment of mixtures of BPA and 4-tBP, facilitating their determination when present at low concentration levels.

Nanoparticle@Metal-Organic Frameworks as a Template for Hierarchical Porous Carbon Sponges.

The preparation of hierarchical porous carbon sponges (HCS) from metal oxide nanoparticle@metal-organic frameworks is reported. ZnO nanoparticles are partially converted to zeolitic imidazolate framework-8 (ZIF-8) crystals in presence of n-butylamine to obtain ZnO@ZIF-8 porous hybrids. After direct carbonization, followed by ZnO acidic etching, ZnO@ZIF-8 crystals were converted to submicrometric HCS. Due to the high surface area and accessible porosity, combining micro- and mesoporosity of HCS, their application for the extraction of water pollutants was studied by preparing HCS/polymer membranes, and showed a high efficiency for the fast (650 L m-2 h-1 ) removal of plastic degradation by-products (DBP, dibutyl phthalate. DEHP, bis(2-n-ethylhexyl)phthalate). DBP and DEHP breakthroughs were lower than 3 % after the filtration of 100 mL of water containing simultaneously both phthalates at a high concentration level (300 µg L-1 , each). HCS/polymer membranes were reusable up to 5 times, maintaining their extraction capacity, with relative errors of 6 % for DBP, and <1 % for DEHP.

Incorporation of zeolitic imidazolate framework (ZIF-8)-derived nanoporous carbons in methacrylate polymeric monoliths for capillary electrochromatography.

A series of metal organic frameworks-derived nanoporous carbons originating from zeolitic imidazolate framework-8 (ZIF-8) crystals as precursors have been prepared via varying the preparation conditions. The ZIF-8-derived carbons were subsequently admixed in the methacrylate monomers containing polymerization mixtures and polymerized to obtain monolithic columns for capillary electrochromatography (CEC). The effect of particle size and content of the ZIF-8-derived carbon materials in the polymerization mixture on the performance of the hybrid monolithic columns was investigated in detail. The resulting composites were characterized using scanning electron microscopy. Using short time UV-initiated polymerization, monolithic beds with homogenously dispersed ZIF-8-derived carbons were obtained. The chromatographic performance of these composites was demonstrated with separations of polycyclic aromatic hydrocarbons and non-steroidal anti-inflammatory drugs as test solutes. The incorporation of the ZIF-8-derived carbons into the organic polymer monoliths led to an increase in the retention of all the analytes compared to the parent monolith. Finally, the hybrid monolithic columns exhibited satisfactory run-to-run and batch-to-batch reproducibility.

Superior Activity of Isomorphously Substituted MOFs with MIL-100(M=Al, Cr, Fe, In, Sc, V) Structure in the Prins Reaction: Impact of Metal Type.

The catalytic behavior of isomorphously substituted MIL-100(M) (M=Al, Cr, Fe, In, Sc, V) is investigated for the synthesis of nopol through the Prins condensation of ß-pinene with paraformaldehyde. The large mesoporous cages of the metal-organic frameworks provide a sustainable confinement for the formation of the target product (100 % selectivity for nopol over all materials studied). MIL-100(Sc) and MIL-100(V) exhibit the highest yields (up to 90 %) of nopol after just 20 min from the beginning of the reaction, owing to their high concentrations of accessible Lewis sites possessing intermediate acidity. The high catalytic activity (reaching almost 90 % ß-pinene conversion) even upon decreasing the amount of catalyst from 100 to 25 mg (0.025 and 0.0063 gcatalyst mmolsubstrate -1 , respectively), the stability of its structure, and the possibility to use it several times, make MIL-100(V) a promising material for applications in acid-catalyzed reactions under mild reaction conditions.