Copper single-site engineering in MOF-808 membranes for improved water treatment

MOF-808, a metal-organic framework containing Zr6O8 clusters, can serve as a secure anchoring point for stabilizing copper single-sites with redox activity, thus making it a promising candidate for catalytic applications. In this study, we target the incorporation of Cu-MOF-808 into a mixed-matrix membrane for the degradation of tyrosol, an emerging endocrine-disrupting compound commonly found in water sources, through Fenton reactions, developing innovative technologies for water treatment. We successfully demonstrate the effectiveness of this approach by preparing catalytic membranes with minimal metal leaching, which is one of the primary challenges in developing copper-based Fenton heterogeneous catalysts. Furthermore, we utilized advanced synchrotron characterization techniques, combining X-ray absorption spectroscopy and pair distribution function analysis of X-ray total scattering, to provide evidence of the atomic structure of the catalytic copper sites within the membranes. Additionally, we observed the presence of weak interactions between the MOF-808 and the organic polymer, potentially explaining their enhanced stability.

A Straightforward Method to Prepare MOF-Based Membranes via Direct Seeding of MOF-Polymer Hybrid Nanoparticles

Metal Organic Frameworks (MOFs) present high surface areas, various pore topology as well as good stabilities. The functionalities and porosity can be tuned by using different linkers with various functional groups and a wide range of linker lengths. These properties make them good candidates in membrane separation applications. In this work, we propose a simple UiO-66 MOF-based membrane fabrication method following two steps. First, the α-alumina tubular membrane support was dip-coated with MOF-polymer hybrid nanoparticles (NPs). These NPs were prepared via one-pot synthesis by adding poly (methacrylic acid)-b-poly (methyl methacrylate) (PMAA-b-PMMA) NPs to the classical acetic acid-modulated UiO-66 or UiO-66-NH₂ synthesis formulation. Second, secondary membrane growth was applied to give rise to a continuous and homogeneous crystalline MOF membrane layer. The gas permeances (He, N₂, CO₂ and SF₆) tests confirmed high membrane permeability with no macro-defects. The as-prepared membranes that were used for dye separation (Rhodamine B) showed relatively good separation capacity.

A systematic study of a polymer-assisted carboxylate-based MOF synthesis: multiple roles of core cross-linked PMAA-b-PMMA nanoparticles

Colloidaly stable carboxylate-based metal organic frameworks (MOFs), grown from acid decorated nanoparticles synthesized via PISA.

How Reproducible are Surface Areas Calculated from the BET Equation?

Porosity and surface area analysis play a prominent role in modern materials science. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory, which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro- and mesoporous materials. Despite its widespread use, the calculation of BET surface areas causes a spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, for this analysis, 18 already-measured raw adsorption isotherms were provided to sixty-one labs, who were asked to calculate the corresponding BET areas. This round-robin exercise resulted in a wide range of values. Here, the reproducibility of BET area determination from identical isotherms is demonstrated to be a largely ignored issue, raising critical concerns over the reliability of reported BET areas. To solve this major issue, a new computational approach to accurately and systematically determine the BET area of nanoporous materials is developed. The software, called "BET surface identification" (BETSI), expands on the well-known Rouquerol criteria and makes an unambiguous BET area assignment possible.

Metal and Covalent Organic Frameworks for Membrane Applications

Better and more efficient membranes are needed to face imminent and future scientific, technological and societal challenges. New materials endowed with enhanced properties are required for the preparation of such membranes. Metal and Covalent Organic Frameworks (MOFs and COFs) are a new class of crystalline porous materials with large surface area, tuneable pore size, structure, and functionality, making them a perfect candidate for membrane applications. In recent years an enormous number of articles have been published on the use of MOFs and COFs in preparation of membranes for various applications. This review gathers the work reported on the synthesis and preparation of membranes containing MOFs and COFs in the last 10 years. Here we give an overview on membranes and their use in separation technology, discussing the essential factors in their synthesis as well as their limitations. A full detailed summary of the preparation and characterization methods used for MOF and COF membranes is given. Finally, applications of these membranes in gas and liquid separation as well as fuel cells are discussed. This review is aimed at both experts in the field and newcomers, including students at both undergraduate and postgraduate levels, who would like to learn about preparation of membranes from crystalline porous materials.

Covalent organic framework nanosheets: preparation, properties and applications

Covalent organic frameworks are crystalline porous materials with 2- or 3-dimensional structures designed modularly from their molecular precursors. Using bottom-up or top-down strategies, single- or few-layer materials can be obtained from them.

Textile/metal-organic-framework composites as self-detoxifying filters for chemical-warfare agents

The current technology of air-filtration materials for protection against highly toxic chemicals, that is, chemical-warfare agents, is mainly based on the broad and effective adsorptive properties of hydrophobic activated carbons. However, adsorption does not prevent these materials from behaving as secondary emitters once they are contaminated. Thus, the development of efficient self-cleaning filters is of high interest. Herein, we report how we can take advantage of the improved phosphotriesterase catalytic activity of lithium alkoxide doped zirconium(IV) metal-organic framework (MOF) materials to develop advanced self-detoxifying adsorbents of chemical-warfare agents containing hydrolysable P-F, P-O, and C-Cl bonds. Moreover, we also show that it is possible to integrate these materials onto textiles, thereby combining air-permeation properties of the textiles with the self-detoxifying properties of the MOF material.

Toxic gas removal – metal–organic frameworks for the capture and degradation of toxic gases and vapours

The adsorptive and catalytic properties of metal–organic frameworks are advantageous for the capture, sensing and degradation of harmful gases and vapors.

A linear model suitable for assessing graft patency in controlled clinical trials. SINBA Group

In clinical trials carried out to assess the efficacy of different drugs in reducing the frequency of occlusion after coronary artery bypass, the ratio of the number of patients with at least one occluded anastomosis to the number of patients catheterized up to a given day is a widely adopted statistic. In the early evaluation (at 1 or 2 months after surgery), this is affected by the distribution of timing of angiography and it tends to underestimate the cumulative probability of occlusion because patients whose anastomoses are all patent at angiography and occlude between angiography and the day at which the ratio is estimated do not contribute their events to the numerator of the ratio. One may sensibly assume that this underestimate does not affect the evaluation of the efficacy of treatments tested "within" the trial. In contrast, since the distributions of the timing of angiography vary substantially from trial to trial, it can make comparisons "between" trials unclear and possibly biased. The aim of this article is to suggest an alternative approach of statistical analysis in terms of logistic regression. By modeling the dichotomous response given by each patient in function of time at angiography, type of treatment, and other possible covariates, asymptotically unbiased estimates of the cumulative probability of occlusion are attained. Furthermore, the pertinent hazard function can be estimated. The main features of the model are discussed and the results obtained by fitting early data collected in the Studio Indobufen Nel Bypass Aortocoronarico (SINBA) are given.