Construction of multifunctional NH2-UiO-66 metal organic framework: sensing and photocatalytic degradation of ketorolac tromethamine and tetracycline in aqueous medium

Photo-thermal conversion properties of MXene/metal-organic-frameworks-based nanofluids for solar energy harvesting

This study focuses on enhancing solar energy capture efficiency by introducing innovative hybrid nanofluids for use in solar thermal collectors, whose performance largely depends on the absorption properties of the working fluid. The newly developed hybrid nanofluids, MXene/NH2-UiO66 (Zr) (noted as MX/UO66) and MXene/MIL-88B (Fe) (noted as MX/ML88), were synthesized using an in-situ solvothermal method, combining annealed Ti3C2Tx MXenes with water-stable metal-organic frameworks (MOFs). These nanofluids achieved high efficiency at low concentrations, providing both economic and performance benefits. Comprehensive testing compared the photothermal properties of these hybrids with single-component UO66 and ML88 nanofluids. The MX structures significantly expanded the absorption range and intensity for UO66 and ML88, with MXUO66 and MXML88 displaying superior thermal conductivity and light absorption compared to single-component fluids. At a concentration of 220 ppm, MXUO66 and MXML88 achieved photothermal efficiencies of 85 % and 79 %, respectively, improving by 24.5 % and 11.3 % over UO66 and ML88 alone. Results indicate that the MX-UO66 combination is particularly effective, demonstrating the strong potential of these composites for optimizing solar energy systems. This work highlights the capability of nanoporous materials with enhanced photothermal properties, underscoring their adaptability for various solar applications and the importance of optimizing collector designs to minimize heat losses.

Hydrogen-rich syngas upgrading via CO2 adsorption by amine-functionalized Cu-BTC: the effect of different amines

Syngas produced from supercritical water gasification typically contain a high amount of CO2 along with H2. In order to improve the quality of syngas, amine-functionalized copper benzene-1,3,5-tricarboxylate (Cu-BTC) was synthesized as an effective adsorbent for selective removal of CO2 from syngas to increase the concentration of H2. The amines used in this study included monoethanolamine (MEA), ethylenediamine (EDA), and polyethyleneimine (PEI). The fundamental physicochemical character of adsorbents, CO2 adsorption capacity, and CO2/H2 selectivity were analyzed. The physicochemical characterization indicated that the structure of amine-functionalized Cu-BTC was partially damaged, which resulted in a decrease in specific surface area and pore volume. On the other hand, the enlarged pore size was beneficial for the mass transfer of gas in the adsorbent. Among these adsorbents, Cu-BTC/PEI exhibited the maximum CO2 adsorption capacity of 3.83 mmol/g and the highest CO2/H2 selectivity of 19.74. It was found that the adsorption pressure is the most significant factor for the CO2 adsorption capacity. Lower temperature and higher pressure were favored for CO2 adsorption capacity and CO2/H2 selectivity, so physical adsorption by Cu-BTC played a dominant role. Moreover, Cu-BTC/PEI can be well-regenerated with stable adsorption efficiency after five consecutive cycles. These findings suggested that Cu-BTC/PEI could be a promising alternative adsorbent for CO2 capture from syngas.

Fabrication of samarium doped MOF-808 as an efficient photocatalyst for the removal of the drug cefaclor from water

MOFs are emerging photocatalysts designed by tuning organic ligands and metal centers for optimal efficiency. In this study, a samarium decorated MOF-808(Ce) metal organic framework was fabricated by facile hydrothermal synthesis. The synthesized samarium decorated MOF-808(Ce) was characterized by using analytical techniques such as SEM, EDX, XRD and TGA to study its morphological, thermal and structural properties. SEM images showed that MOF-808(Ce) comprised of truncated octahedrons. The morphology of the material was changed upon Sm incorporation. Sm/MOF-808(Ce) exhibited better UV-vis light absorption properties than MOF-808(Ce) as evidenced by its slightly higher band gap value. This material was exploited for the degradation of the drug cefaclor from water. Cefaclor removal followed double a first order in parallel model (DFOP). Under UV light, 97.7% of the cefaclor was removed in only 20 minutes and after 60 minutes this removal efficiency was increased to 99.25%. These features exhibited that samarium decorated MOF has immense potential for the photocatalytic degradation of cefaclor as it generates e- and h+ to enhance the photocatalytic efficiency and it is a promising candidate to treat wastewater without formation of harmful byproducts.

Ketorolac removal through photoelectrocatalysis using TiO2 nanotubes in water system

Ketorolac, a highly persistent NSAID of environmental concern, was significantly removed from water (80% removal) through photoelectrocatalysis where titanium dioxide nanotubes prepared by Ti foil electrochemical anodization at 30 V were used as photoanodes. Fifteen milligrams per liter of ketorolac solutions in a 0.05 M Na2SO4 aqueous medium was subjected to irradiation from a 365-nm light with an intensity of 1 mWcm-2 and under an applied potential of 1.3 V (vs. Hg/Hg2SO4/sat.K2SO4) at pH 6.0. When each process (photo and electrocatalysis) was carried out separately, less than 20% drug removal was achieved as monitored through UV-vis spectrophotometry. Through scavenging experiments, direct oxidation on the photogenerated holes and oxidation by hydroxyl radical formation were found to play a key role on ketorolac's degradation. Chemical oxygen demand (COD) analyses also showed a significant COD decreased (68%) since the initial COD value was 31.3 mg O2/L and the final COD value was 10.1 mg O2/L. A 48% mineralization was also achieved, as shown by total organic carbon (TOC) analyses. These results showed that electrodes based on titania nanotubes are a promising alternative material for simultaneous photocatalytic and electrocatalytic processes in water remediation.

Solution Shearing of Zirconium (Zr)-Based Metal-Organic Frameworks NU-901 and MOF-525 Thin Films for Electrocatalytic Reduction Applications

Solution shearing, a meniscus-guided coating process, can create large-area metal-organic framework (MOF) thin films rapidly, which can lead to the formation of uniform membranes for separations or thin films for sensing and catalysis applications. Although previous work has shown that solution shearing can render MOF thin films, examples have been limited to a few prototypical systems, such as HKUST-1, Cu-HHTP, and UiO-66. Here, we expand on the applicability of solution shearing by making thin films of NU-901, a zirconium-based MOF. We study how the NU-901 thin film properties (i.e., crystallinity, surface coverage, and thickness) can be controlled as a function of substrate temperature and linker concentration. High fractional surface coverage of small-area (∼1 cm2) NU-901 thin films (0.88 ± 0.06) is achieved on a glass substrate for all conditions after one blade pass, while a low to moderate fractional surface coverage (0.73 ± 0.18) is obtained for large-area (∼5 cm2) NU-901 thin films. The crystallinity of NU-901 crystals increases with temperature and decreases with linker concentration. On the other hand, the adjusted thickness of NU-901 thin films increases with both increasing temperature and linker concentration. We also extend the solution shearing technique to synthesize MOF-525 thin films on a transparent conductive oxide that are useful for electrocatalysis. We show that Fe-metalated MOF-525 films can reduce CO2 to CO, which has implications for CO2 capture and utilization. The demonstration of thin film formation of NU-901 and MOF-525 using solution shearing on a wide range of substrates will be highly useful for implementing these MOFs in sensing and catalytic applications.

Solar-light-driven photocatalytic degradation of pharmaceutical pollutants utilizing 2D g-C3N4/BiOCl composite

Pharmaceuticals, which have been praised for protecting countless lives, have become a new category of environmental pollutants in recent decades as most of these pharmaceutical compounds are discovered in water bodies in concentrations ranging from ng/L to mg/L. Recently, metal-free g-C₃N₄ (GCN)-based composites have received considerable attention for the degradation of pharmaceutical compounds. In this study, GCN/BiOCl composite was prepared using a simple ultrasonication-assisted stirring method and characterized using various analytical and spectroscopic techniques including XRD, FTIR, PL, Elemental mapping, UV-DRS, FESEM, HRTEM, and TGA. The as-prepared composite was utilized to degrade levofloxacin (LVX) under solar light irradiation and showed excellent stability for the degradation of LVX. Furthermore, the universality of the GCN/BiOCl composite was investigated by degrading diverse pharmaceuticals such as ofloxacin (OFX), norfloxacin (NOX), ciprofloxacin (COX), and ketorolac tromethamine (KTC) in an aqueous phase. Therefore, this work provides an effective method to degrade pharmaceutical contaminants simultaneously in water using GCN/BiOCl composite.

Peroxymonosulphate Activation by Basolite® F-300 for Escherichia coli Disinfection and Antipyrine Degradation

In this study, the removal of persistent emerging and dangerous pollutants (pharmaceuticals and pathogens) in synthetic wastewater was evaluated by the application of heterogeneous Advanced Oxidation Processes. To do that, a Metal-Organic Framework (MOF), Basolite® F-300 was selected as a catalyst and combined with peroxymonosulfate (PMS) as oxidants in order to generate sulphate radicals. Several key parameters such as the PMS and Basolite® F-300 concentration were evaluated and optimized using a Central Composite Experimental Design for response surface methodology for the inactivation of Escherichia coli. The assessment of the degradation of an analgesic and antipyretic pharmaceutical, antipyrine, revealed that is necessary to increase the concentration of PMS and amount of Basolite® F-300, in order to diminish the treatment time. Finally, the PMS-Basolite® F-300 system can be used for at least four cycles without a reduction in its ability to disinfect and degrade persistent emerging and dangerous pollutants such as pharmaceuticals and pathogens.

TiO2-La2O3 as Photocatalysts in the Degradation of Naproxen

The indiscriminate use of naproxen as an anti-inflammatory has been the leading cause of pollution in sewage effluents. Conversely, titanium dioxide is one of the most promising photocatalyst for the degradation of pollutants. Ti-La mixed oxides containing 0, 1, 3, 5, and 10 wt.% of lanthanum were synthetized by sol-gel and tested as photocatalysts in the degradation of naproxen (NPX). The materials were further characterized by X-ray diffraction (XRD), nitrogen physisorption (BET), scanning electron microscopy (SEM), UV-Vis and Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The XRD patterns resembled that of anatase titania. The Eg values, determined from the UV-Vis spectra, vary from 2.07 to 3.2 eV corresponded to pure titania. The photocatalytic activity of these materials showed a degradation of naproxen from 93.6 to 99.8 wt.% after 4 h under UV irradiation.