Unveiling nano-empowered catalytic mechanisms for PFAS sensing, removal and destruction in water.

Per- and polyfluoroalkyl substances (PFAS) are organofluorine compounds used to manufacture various industrial and consumer goods. Due to their excellent physical and thermal stability ascribed to the strong CF bond, these are ubiquitously present globally and difficult to remediate. Extensive toxicological and epidemiological studies have confirmed these substances to cause adverse health effects. With the increasing literature on the environmental impact of PFAS, the regulations and research have also expanded. Researchers worldwide are working on the detection and remediation of PFAS. Many methods have been developed for their sensing, removal, and destruction. Amongst these methods, nanotechnology has emerged as a sustainable and affordable solution due to its tunable surface properties, high sorption capacities, and excellent reactivities. This review comprehensively discusses the recently developed nanoengineered materials used for detecting, sequestering, and destroying PFAS from aqueous matrices. Innovative designs of nanocomposites and their efficiency for the sensing, removal, and degradation of these persistent pollutants are reviewed, and key insights are analyzed. The mechanistic details and evidence available to support the cleavage of the CF bond during the treatment of PFAS in water are critically examined. Moreover, it highlights the challenges during PFAS quantification and analysis, including the analysis of intermediates in transitioning nanotechnologies from the laboratory to the field.

Fabrication, functionalization and advanced applications of magnetic hollow materials in confined catalysis and environmental remediation.

Magnetic hollow-structured functional hybrid materials with unique architectures and preeminent properties have always been an area of extensive research. They represent a subtle collaboration of hollow architecture, mesoporous nanostructure and magnetic character. Owing to the merits of a large void space, low density, high specific surface area, well-defined active sites and facile magnetic recovery, these materials present promising application projections in numerous fields, such as drug delivery, adsorption, storage, catalysis and many others. In this review, recent progress in the design, synthesis, functionalization and applications of magnetic hollow-meso/nanostructured materials are discussed. The first part of the review has been dedicated to the preparation and functionalization of the materials. The synthetic protocols have been broadly classified into template-assisted and template-free methods and major trends in their synthesis have been elaborated in detail. Furthermore, the benefits and drawbacks of each method are compared. The later part summarizes the application aspects of confined catalysis in organic transformations and environmental remediation such as degradation of organic pollutants, dyes and antibiotics and adsorption of heavy metal ions. Finally, an outlook of future directions in this research field is highlighted.

An Efficient and Sustainable Approach to Decarboxylative Cross-Coupling Using Silica Coated Magnetic Copper Nanocatalyst for the Synthesis of Internal Alkynes.

A highly efficient magnetically separable copper nanocatalyst has been developed for decarboxylative cross-coupling reaction for the alkynylation of haloarenes using alkynoic acid as a reaction partner. The chemical nature, morphology, size, and magnetic properties of the prepared nanocatalyst were studied by SEM, TEM, EDS, FT-IR, VSM, and ICP techniques. Remarkably, this catalyst represents the first successful copper based heterogeneous system for this type of coupling that provides a low-cost, stable, and environmentally friendly magnetically recoverable entity that can be re-used for seven consecutive runs without appreciable loss in its catalytic performance.

A template free protocol for fabrication of a Ni(ii)-loaded magnetically separable nanoreactor scaffold for confined synthesis of unsymmetrical diaryl sulfides in water.

In the present report, an environmentally benign magnetically recoverable nickel(ii)-based nanoreactor as a heterogeneous catalyst has been developed via a template free approach. The catalytic performance of the synthesized catalyst is assessed in the confined oxidative coupling of arenethiols with arylhydrazines to form unsymmetrical diaryl sulfides under aerobic conditions. The salient features of our protocol include oxidant- and ligand-free conditions, use of water as a green solvent, room temperature and formation of nitrogen and water as the only by-products. Moreover, a broad range of functional groups are tolerated well and provide the corresponding diaryl sulfides in moderate to good yields. Moreover, the heterogeneous nature of the catalyst permits facile magnetic recovery and reusability for up to seven runs, making the present protocol highly desirable from industrial and environmental standpoints.

Silica-Coated Magnetic-Nanoparticle-Supported DABCO-Derived Acidic Ionic Liquid for the Efficient Synthesis of Bioactive 3,3-Di(indolyl)indolin-2-ones.

In this work, biologically significant 3,3-di(indolyl)indolin-2-ones have been synthesized using a silica-coated magnetic-nanoparticle-supported 1,4-diazabicyclo[2.2.2]octane (DABCO)-derived and acid-functionalized ionic liquid as the catalytic entity. The fabricated nanocomposite catalyzes the pseudo-three-component reaction of isatins and indoles explicitly via hydrogen-bonding interactions between substrates and the catalyst. The nanocatalytic system utilizes water as the green reaction medium to obtain a library of indolinones in good to excellent yields under mild reaction conditions. Besides, the catalyst could be easily recovered from the reaction mixture through simple external magnetic forces, which enables excellent recyclability of the catalyst for successive runs without appreciable loss in catalytic activity. Hence, the outcomes of the present methodology make the nanocatalyst a potential candidate for the development of green and sustainable chemical processes.

An efficient copper-based magnetic nanocatalyst for the fixation of carbon dioxide at atmospheric pressure.

In the last few decades, the emission of carbon dioxide (CO2) in the environment has caused havoc across the globe. One of the most promising strategies for fixation of CO2 is the cycloaddition reaction between epoxides and CO2 to produce cyclic carbonates. For the first time, we have fabricated copper-based magnetic nanocatalyst and have applied for the CO2 fixation. The prepared catalyst was thoroughly characterized using various techniques including XRD, FT-IR, TEM, FE-SEM, XPS, VSM, ICP-OES and elemental mapping. The reactions proceeded at atmospheric pressure, relatively lower temperature, short reaction time, solvent- less and organic halide free reaction conditions. Additionally, the ease of recovery through an external magnet, reusability of the catalyst and excellent yields of the obtained cyclic carbonates make the present protocol practical and sustainable.

Synthesis of Iron Oxide Palladium Nanoparticles and Their Catalytic Applications for Direct Coupling of Acyl Chlorides with Alkynes.

A new, magnetic, silica-based, palladium nanocatalyst has been synthesized and employed for the first time in the direct coupling of acyl chlorides with terminal alkynes to prepare a variety of ynones. The synthesized nanocomposite is an excellent heterogeneous catalyst for copper-free, phosphine-free, C-C bond formation through the Sonogashira reaction under aerobic conditions at room temperature without the use of any additives and inert conditions. The synthesized catalyst has been comprehensively characterized by various techniques, such as XRD, SEM, TEM, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, FTIR spectroscopy, vibrating sample magnetometry, and atomic absorption spectroscopy. This nanocatalyst can be magnetically recovered and reused in multiple runs without any noticeable loss in catalytic activity.