This review sheds some light on the emerging niche of the reuse of spent adsorbents in electrochemical devices. Reuse and repurposing extend the adsorbent’s life cycle, remove the need for long-term storage, and generate additional value, making it a highly eco-friendly process. Main adsorbent-type materials are overviewed, emphasising desired properties for initial adsorption and subsequent conversion to electroactive material step. The effects of the most frequent regeneration procedures are compared to highlight their strengths and shortcomings. The latest efforts of repurposing and reuse in supercapacitors, fuel cells, and batteries are analysed. Reuse in supercapacitors is dominated by materials that, after a regeneration step, lead to materials with high surface area and good pore structure and is mainly based on the conversion of organic adsorbents to some form of conductive carbon adlayer. Additionally, metal/metal-oxide and layered-double hydroxides are also being developed, but predominantly towards fuel cell and battery electrodes with respectable oxygen reduction characteristics and significant capacities, respectively. Repurposed adsorbents are being adopted for peroxide generation as well as direct methanol fuel cells. The work puts forward electrochemical devices as a valuable avenue for spent adsorbents and as a puzzle piece towards a greener and more sustainable future.

This study investigated the environmental application of FAU type zeolites modified with cationic surfactants which act as promising adsorbents for tannic acid and pesticide and modulators of pesticide cytotoxicity.

Ecotoxicity caused by neonicotinoid pesticides is largely due to oxidative stress on non-target species. Due to the fact that reactive radical species reach the environment, materials intended for pesticide removal should be applicable for the simultaneous removal of reactive radicals, as well. This work uses the spectroscopic, adsorptive and antioxidant responses from MFI, FAU and BEA zeolites as descriptors of their potential environmental importance. Different network structures and Si/Al ratios were correlated with excellent zeolite adsorption properties, as over 200 mg g⁻¹ of investigated neonicotinoids, acetamiprid and imidacloprid, was achieved in one cycle. Additionally, after two regeneration steps, over 450 mg g⁻¹ adsorbed pesticides were retained, in three adsorption cycles. Overall the best results were detected for the FAU zeotype in both tested applications, insecticide adsorption and radical-scavenging performance, with and without insecticides present. The proposed mechanism for adsorption relies on kinetic investigation, isotherm modelling and spectroscopic post-adsorption analysis and targets zeolite hydroxyl/siloxane groups as active sites for insecticide adsorption via hydrogen bonding. Neat, well-defined zeolite structures enable their prospective application in ecotoxic species removal.

Neutrophils release decondensed chromatin or extracellular traps (NETs) in response to various physiological and pharmacological stimuli. Apart from host defensive functions, NETs play an essential role in the pathogenesis of various autoimmune, inflammatory, and malignant diseases. In recent years, studies have been performed on photo-induced NET formation, mainly activated by UV radiation. Understanding the mechanisms of NET release under the influence of UV and visible light is important to control the consequences of the damaging effects of electromagnetic radiation. Raman spectroscopy was applied to record characteristic Raman frequencies of various reactive oxygen species (ROS) and low-frequency lattice vibrational modes for citrulline. NETosis was induced by irradiation with wavelength-switchable LED sources. Fluorescence microscopy was used to visualize and quantify NET release. The ability of five wavelengths of radiation, from UV-A to red light, to induce NETosis was investigated at three different energy doses. We demonstrated, for the first time, that NET formation is activated not only by UV-A but also by three spectra of visible light: blue, green, and orange, in a dose-dependent manner. Using inhibitory analysis, we established that light-induced NETosis proceeds through NADPH oxidase and PAD4. The development of new drugs designed to suppress NETosis, especially when induced by exposure to intense UV and visible light, can help to mitigate light-induced photoaging and other damaging effects of electromagnetic radiation.

The environmental application of the carbonized composites of the Zn-containing metal-organic framework MOF-5 and polyaniline (PANI) in its emeraldine salt and base forms (C-(MOF-5/PANI)) was investigated for the first time. Textural properties and particle size distributions revealed that composites are dominantly mesoporous and nanoscale in nature, while Raman spectroscopy revealed the ZnO phase beneath the carbon matrix. Adsorption of pesticide, dye, and metal cation on C-(MOF-5/PANI) composites in aqueous solutions was evaluated and compared with the behavior of the precursor components, carbonized MOF-5 (cMOF), and carbonized PANIs. A lower MOF-5 content in the precursor, a higher specific surface area, and the pore volume of the composites led to improved adsorption performance for acetamiprid (124 mg/g) and Methylene Blue (135 mg/g). The presence of O/N functional groups in composites is essential for the adsorption of nitrogen-rich pollutants through hydrogen bonding with an estimated monolayer capacity twice as high as that of cMOF. The proton exchange accompanying Cd²⁺ retention was associated with the Zn/Cd ion exchange, and the highest capacity (9.8 mg/g) was observed for the composite synthesized from the precursor with a high MOF-5 content. The multifunctionality of composites was evidenced in mixtures of pollutants where noticeably better performance for Cd²⁺ removal was found for the composite compared to cMOF. Competitive binding between three pollutants favored the adsorption of pesticide and dye, thereby hindering to some extent the ion exchange necessary for the removal of metal cations. The results emphasize the importance of the PANI form and MOF-5/PANI weight ratio in precursors for the development of surface, porosity, and active sites in C-(MOF-5/PANI) composites, thus guiding their environmental efficiency. The study also demonstrated that C-(MOF-5/PANI) composites retained studied pollutants much better than carbonized precursor PANIs and showed comparable or better adsorption ability than cMOF.