Acute Cr VI water pollution duet oa nthropogenic activities is an increasing worldwide concern. The high toxicity and mobility of Cr VI makesi tn ecessary to develop dual adsorbent/ion-reductive materialst hat are able to capture Cr VI and transform it efficiently into the less hazardous Cr III. An accurated escription of chromium speciationa tt he adsorbent/ion-reductive matrix is key to assessing whether Cr VI is completely reduced to Cr III ,o ri fi ts incomplete transformation has led to the stabilization of highly reactive, transient Cr V species within the material. With this goal in mind, a dual ultraviolet-visible and electron paramagnetic spectroscopy approachh as been applied to determine the chromium speciation within zirconium-basedm etal-organic frameworks (MOFs). Our findings point out that the generation of defects at Zr-MOFs boosts Cr VI adsorption, whilst the presence of reductiveg roups on the organic linkersp lay ak ey role in stabilizing it as isolated and/or clustered Cr III ions.

In this paper, the potential of 2D printing technologies to create thin film gas sensors from ionic liquid (IL)/metal-organic framework (MOF) composites is evaluated. To accomplish this, the MOF is synthesized solvothermally, and impregnated with the IL. The structure and basic properties of the IL/ MOF composites are characterized using thermal, spectroscopic, and X-ray diffraction techniques, and the resultant sensing capacity of the bulk material is evaluated by impedance spectroscopy. The IL/MOF systems are then integrated into a 2D printed silver capacitive circuit by spray and tested on a custom-made gas flow apparatus. Exposure of the IL/MOF based sensors to water, acetone, and ethanol induces a repetitive variation of the capacitance (from 0.05 to 7 pF) that is dependent on the nature of the gas. IL/MOF based sensors can detect changes in concentrations in the range of 10k-100k ppm in less than a second. The conclusions of this work are the first steps towards the development of 2D printed sensors based on IL/MOF materials. Such materials offer countless possibilities to tailor the porosity, chemistry, selectivity, and electrical response to make the sensor suitable to detect the desired analyte.

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The presence of hexavalent chromium water pollution is a growing global concern. Among the currently applied technologies to remove CrVI, its adsorption and photocatalytic reduction to CrIII less mobile and toxic forms are the most appealing because of their simplicity, reusability, and low energy consumption. However, little attention has been paid to bifunctional catalysts, that is, materials that can reduce CrVI to CrIII and retain both hexavalent and trivalent chromium species at the same time. In this work, the dual CrVI adsorption–reduction capacity of two iconic photoactive water-stable zirconium and titanium-based metal–organic frameworks (MOFs) has been investigated: UiO-66-NH2 and MIL-125. The bifunctionality of photoactive MOFs depends on different parameters, such as the particle size in MIL-125 or organic linker functionalization/defective positions in UiO-66 type sorbents. For instance, the presence of organic linker defects in UiO-66 has shown to be detrimental for the chromium photoreduction but beneficial for the retention of the CrIII phototransformed species. Both compounds are able to retain from 90 to 98% of the initial chromium present at acidic solutions as well as immobilize the reduced CrIII species, demonstrating the suitability of the materials for CrVI environmental remediation. In addition, it has been demonstrated that adsorption can be carried out also in a continuous flux mode through a diluted photoactive MOF/sand chromatographic column. The obtained results open the perspective to assess the bifunctional sorption and photoreduction ability of a plethora of MOF materials that have been applied for chromium capture and photoreduction purposes. In parallel, this work opens the perspective to develop specific chemical encoding strategies within MOFs to transfer this bifunctionality to other related water remediation applications.

Magnetoelastic resonators are gaining attention as an incredibly versatile and sensitive transduction platform for the detection of varied physical, chemical, and biological parameters. These sensors, based on the coupling effect between mechanical and magnetic properties of ME platforms, stand out in comparison to alternative technologies due to their low cost and wireless detection capability. Several parameters have been optimized over the years to improve their performance, such as their composition, surface functionalization, or shape geometry. In this review, the working principles, recent advances, and future perspectives of magnetoelastic resonance transducers are introduced, highlighting their potentials as a versatile platform for sensing applications. First, the fundamental principles governing the magnetoelastic resonators performance are introduced as well as the most common magnetoelastic materials and their main fabrication methods are described. Second, the versatility and technical feasibility of magnetoelastic resonators for biological, chemical, and physical sensing are highlighted and the most recent results and functionalization processes are summarized. Finally, the forefront advances to further improve the performance of magnetoelastic resonators for sensing applications have been identified.

Abstract:The development of polymer membranes with tailored micro-morphology and wettability is a demand in the areas of filtration, sensors, and tissue engineering, among others. The thermoplastic copolymer poly(vinylidene fluoride-cohexafluoropropylene) (PVDF-HFP), is one of the most widely used polymers for these applications due to its good mechanical and thermal properties, biocompatibility and low density. Although the control of the PVDF-HFP morphology is a complicated task, the introduction of ionic liquids (ILs) in the PVDF-HFP matrix opens news perspectives in this area. This

While melt electrowriting (MEW) can result in complex microstructures, research demonstrating such fabrication with active materials is limited. Herein, magnetoresponsive poly(𝝐-caprolactone) (PCL) inks containing up to 10 wt% of iron-oxide (Fe 3 O 4 ) nanoparticles are used to produce fiber with diameters of 9.2 ± 0.6 μm in ordered microstructures when processed by MEW. Introducing the Fe 3 O 4 nanoparticles has a minimal overall effect on printing quality compared to pure PCL under similar conditions. The magnetic response of Fe 3 O 4 containing fibers allows magnetic actuation, which is one of the first steps to control movement in such structures. Printed samples show different magnetic responses that can be controlled by the micro-and macro-structure design, the nanoparticle concentration, and multi-material design. The potential of MEW to print active magnetic complex micro-and macro-structures for 4D printing designs is demonstrated, in which active properties can be further tailored with magnetoresponsive fillers with varying characteristics and by changing MEW fiber diameters.