Enhancing CO2 chemisorption on lithium cuprate (Li2CuO2) at moderate temperatures and different pressures by alkaline nitrate addition.

Lithium, sodium and potassium nitrate-containing Li2CuO2 samples were prepared to analyze the CO2 capture process at moderate temperatures, using different pressure conditions. Initially, in a CO2 saturated atmosphere, all these samples showed high CO2 capture efficiencies between 150 and 350 °C, in comparison to the pristine Li2CuO2 (T≥ 500 °C). These results evidenced that Li-, Na- and K-nitrate addition on Li2CuO2 importantly enhances the whole CO2 capture. These results were corroborated kinetically. Moreover, the effects and reaction mechanism of alkaline nitrate addition were determined by X-ray diffraction, infrared spectroscopy and differential scanning calorimetric analyses. Nitrate anions melt and work as donor/acceptor oxygen anion intermediates during the Li2CuO2 carbonation process. Moreover, the carbonation may be completed (Li2CO3 and CuO production) through Li3Cu2O4 formation. When the CO2 capture process was evaluated using low partial pressures, the results presented similar efficiencies to those obtained using a saturated CO2 condition, showing differences only during the decarbonation process (T > 700 °C), as the CO2 chemisorption-desorption equilibrium was shifted. Finally, pristine Li2CuO2 and alkaline nitrate-containing Li2CuO2 samples were evaluated at high pressures. The pristine Li2CuO2 sample did not show any CO2 capture improvement, while alkaline nitrate-containing Li2CuO2 samples did improve. This was attributed to the alkaline nitrate melting process and the pressure equilibrium conditions.

SO2 capture and detection with carbon microfibers (CMFs) synthesised from polyacrylonitrile.

SO2 emissions not only affect local air quality but can also contribute to other environmental issues. Developing low-cost and robust adsorbents with high uptake and selectivity is needed to reduce SO2 emissions. Here, we show the SO2 adsorption-desorption capacity of carbon microfibers (CMFs) at 298 K. CMFs showed a reversible SO2 uptake capacity (5 mmol g-1), cyclability over ten adsorption cycles with fast kinetics and good selectivity towards SO2/CO2 at low-pressure values. Additionally, CMFs' photoluminescence response to SO2 and CO2 was evaluated.

MFM-300(Sc): a chemically stable Sc(III)-based MOF material for multiple applications.

Developing robust multifunctional metal-organic frameworks (MOFs) is the key to advancing the further deployment of MOFs into relevant applications. Since the first report of MFM-300(Sc) (MFM = Manchester Framework Material, formerly known as NOTT-400), the development of applications of this robust microporous MOF has only grown. In this review, a summary of the applications of MFM-300(Sc), as well as some emerging advanced applications, have been discussed. The adsorption properties of MFM-300(Sc) are presented systematically. Particularly, this contribution is focused on acid and corrosive gas adsorption. In addition, recent applications for catalysis based on the outstanding hemilabile Sc-O bond character are highlighted. Finally, some new research areas are introduced, such as host-guest chemistry and biomedical applications. This highlight aims to showcase the recent advances and the potential for developing new applications of this promising material.

Modulated self-assembly of three flexible Cr(III) PCPs for SO2 adsorption and detection.

Modulated self-assembly protocols are used to develop facile, HF-free syntheses of the archetypal flexible PCP, MIL-53(Cr), and novel isoreticular analogues MIL-53(Cr)-Br and MIL-53(Cr)-NO2. All three PCPs show good SO2 uptake (298 K, 1 bar) and high chemical stabilities against dry and wet SO2. Solid-state photoluminescence spectroscopy indicates all three PCPs exhibit turn-off sensing of SO2, in particular MIL-53(Cr)-Br, which shows a 2.7-fold decrease in emission on exposure to SO2 at room temperature, indicating potential sensing applications.

Gold nanoparticles: current and upcoming biomedical applications in sensing, drug, and gene delivery.

Gold nanoparticles (AuNPs) present unique physicochemical characteristics, low cytotoxicity, chemical stability, size/morphology tunability, surface functionalization capability, and optical properties which can be exploited for detection applications (colorimetry, surface-enhanced Raman scattering, and photoluminescence). The current challenge for AuNPs is incorporating these properties in developing more sensible and selective sensing methods and multifunctional platforms capable of controlled and precise drug or gene delivery. This review briefly highlights the recent progress of AuNPs in biomedicine as bio-sensors and targeted nano vehicles.

Evaluation of Fe-containing Li2CuO2 on CO2 capture performed at different physicochemical conditions.

Li2CuO2 and different iron-containing Li2CuO2 samples were synthesized by solid state reaction. On iron-containing samples, atomic sites of copper are substituted by iron ions in the lattice (XRD and Rietveld analyses). Iron addition induces copper release from Li2CuO2, which produce cationic vacancies and CuO, due to copper (Cu2+) and iron (Fe3+) valence differences. Two different physicochemical conditions were used for analyzing CO2 capture on these samples; (i) high temperature and (ii) low temperature in presence of water vapor. At high temperatures, iron addition increased CO2 chemisorption, due to structural and chemical variations on Li2CuO2. Kinetic analysis performed by first order reaction and Eyring models evidenced that iron addition on Li2CuO2 induced a faster CO2 chemisorption but a higher thermal dependence. Conversely, CO2 chemisorption at low temperature in water vapor presence practically did not vary by iron addition, although hydration and hydroxylation processes were enhanced. Moreover, under these physicochemical conditions the whole sorption process became slower on iron-containing samples, due to metal oxides presence.