Iron is one of the most important metallic elements and covers around 5.05% of the Earth's crust. It has widespread applications in our day-to-day life, from household equipment to large industries. Due to rapid increases in the demand for steel in both the global and domestic market, as well as due to an ongoing depletion of high-grade iron ores, industry actors and policy makers have started considering the utilization of low-grade iron ores. According to the National Steel Policy 2017, India aims to attain a steel production capacity of 300 MT by 2030. In order to achieve this target, we must improve the utilization of low-grade iron ores. In this study, we use a low-grade iron ore, specifically banded hematite jasper (BHJ) from Daitari Iron Ore Mines, Odisha, India. The aim of this study is to understand the morphology, mineralogy, texture, and chemistry of BHJ. The characterization of BHJ is carried out using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), optical microscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The XRD results suggest that quartz is the major gangue mineral, while hematite is the major iron mineral. The XRF analysis shows that the Fe content of BHJ is around 30%, and its SiO₂ content is around 54%, along with minor elements in varying proportions. Optical microscopic studies indicate the presence of alternate bands of hematite and quartz in BHJ, while SEM-EDS demonstrates how iron and silicate phases are associated with each other. This study allows for the optimization of conventional liberation or beneficiation practices for low-grade iron ores.

Lanthanide-doped nanocrystals are widely known systems thanks to their emission characteristics, such as their exceptional thermomechanical properties, chemical stability, large effective Stokes shifts, narrow emission spectra, and long lifetimes. Alkali-earth lanthanide nanophosphors (M₂LnF₇, where M represents Ca, Sr, Ba, etc., and Ln³⁺ stands for Y, La, Gd, Lu, etc.) have been proposed as good host materials. They possess elevated upconversion (UC) luminescence properties and can be grown in dimensions suitable for biomedical imaging applications.

Neodymium (Nd) ions possess intense emissions across various infrared regions, at wavelengths around 900 nm, 1064 nm, and 1300 nm. These emissions originate from transitions between the ⁴F_3/2 state and the lower-lying ⁴I_9/2, ⁴I_11/2, and ⁴I_13/2 energy states, respectively.

In this work, we present a thorough investigation of the spectroscopic properties of Sr₂LaF₇ phosphors with different Nd³⁺ ion concentrations (x=1, 2, 3, and 5 mol%). The samples were synthesized using the hydrothermal method and structurally and morphologically characterized. Powder X-ray diffraction analysis confirmed that the materials crystallize in a cubic crystal structure while transmission electron microscopy shows nanoparticles with an average particle size of ~ 40 nm.

All the Nd³⁺ ion concentrations that we studied present a slightly sublinear trend in the emission spectra as a function of the pump power. This indicates the presence of some loss in the energy transfer processes. Moreover, we studied the emission trend as a function of the concentration at a fixed pump power. This study suggests that the optimum concentration for the maximum emission intensity is 3% Nd. The trend shows a decrease in intensity at higher concentrations.

We will present both the emission trends and the lifetime of the ⁴F_3/2 level as a function of the sample temperature, which will range from -190 °C to 600 °C, with insights into the possible energy transfer processes.

Organic menthol crystals, derived from mint essential oils, are natural, waxy, clear, or white crystalline substances that are solid at room temperature, melting slightly above. Menthol, a cyclic monoterpene alcohol, is synthesized from natural or synthetic precursors and has a significant demand globally, with various protocols available for its synthesis. It is commonly used in perfumery, cosmetics, and medicinal products for its cooling effect and minty scent. Menthol's safety profile and anticancer properties have been extensively studied, showing promising results in inhibiting different cancer cells through multiple pathways like apoptosis induction, cell cycle arrest, and the disruption of tubulin polymerization. Additionally, menthol's impact on respiratory health and digestive issues, and its potential to exacerbate allergic rhinitis have been explored, highlighting both its beneficial and potentially harmful effects on human health.

In this study, we provide an in-depth overview of innovation based on relevant patents related to menthol crystals and its derivatives and their applications. By analyzing these patents, we aim to present the current state of the art and identify emerging trends in the field of plant-derived menthol.

References:

1. Tomar, R.; Kundra, P.; Sharma, J.; Mohajer, F.; Ziarani, M.G.; Yadav, S. An Overview: Synthesis of Menthol using Heterogeneous Catalysis. Letters in Organic Chemistry 2024, 21, 16-28, doi:10.2174/1570178620666230623114308.
2. Zhao, Y.; Pan, H.; Liu, W.; Liu, E.; Pang, Y.; Gao, H.; He, Q.; Liao, W.; Yao, Y.; Zeng, J.; Guo, J. Menthol: An underestimated anticancer agent. Frontiers in pharmacology 2023, 14, doi:10.3389/fphar.2023.1148790.

Recently, there has been considerable interest in the development of crystal scintillators of the Cs₂MCl₆ family of metal hexachlorides (M = Hf or Zr) due to their exceptional properties: high light yield (up to 40000 photons/ MeV ), good linearity in the energy response, excellent energy resolution (< 3.5% at 662 keV in the best configuration) and excellent ability to discriminate between pulse shapes (PSD) of β(γ) and α particles. One Cs₂HfCl₆ (CHC) crystal scintillator was measured, over 2848 h of data taking, deep underground in the STELLA laboratory at the Gran Sasso National Laboratory of the INFN, Italy. Its residual radioactive contaminants were studied and are presented here. The total α activity of the detector was at the level of 7.8(3) mBq/kg. A measurement using two Cs₂ZrCl₆ (CZC) crystal scintillators (11 g and 24 g) was performed in the DAMA/CRYS low-background setup deep underground at LNGS. Chemical purity, residual radioactive contaminants, scintillation, and PSD performance are discussed in this paper. The low-background measurements over 456.5 days demonstrated the crystals’ high radiopurity, showing a counting rate of 0.17(kg·keV·y)^-1 at the Q_2β = 3.35 MeV of ⁹⁶Zr. Another measurement was subsequently carried out using three new CZC crystals and one CHC crystal in optimized geometry. The crystal growth technique, raw material purification, and post-growth material treatment are discussed here. Moreover, the three CZC crystals were grown using starting materials with different purities to study their resulting characteristics and were encapsulated using a silicone-based sealant. The results obtained are presented in this paper.

There is strong evidence that many natural phenomena could be described using geometrical approaches. Consequently, it is of interest to identify experimentally accessible systems in which universality of geometry-based approaches could be tested or/and investigated in detail. Testbed laboratory systems (i.e., analogs) could serve as gateways toward a deeper understanding of phenomena in other ways hardly or even experimentally inaccessible systems that are mathematically related to such analogs.

Diverse liquid crystalline (LC) phases and configurations are ideal candidates for such purposes. These optically anisotropic soft matter representatives combine properties of ordered crystals and liquids, and exhibit rich diversity of different symmetries. Their states could be well described by mesoscopic molecular fields, which could be easily manipulated by diverse external stimuli, and the resulting field-configurations could be probed using relatively simple and inexpensive optical methods (e.g., optical polarizing microscopy).

In our presentation we intend to illustrate how phenomena studied in LCs could be exploited to get insight into open problems of particle physics and cosmology. In particular, we address (i) the Kibble-Zurek mechanism describing coarsening dynamics of the Higgs field in the early universe, (ii) the stabilization and manipulation of skyrmion-family structures (these quasiparticle configurations were originally proposed to describe hadrons and mesons) and (iii) the stabilization and manipulation of fermionic Weyl-type excitations. We also (iv) illustrate analogs of “virtual particles”, and suggest a possible origin of (v) dark matter and (vi) of the asymmetry between “particles” and “antiparticles” in the Universe.

Catalysts are indispensable in accelerating chemical reactions, and numerous chemical
industries rely on heterogeneous catalysts to efficiently transform raw materials into final
products. The petroleum, petrochemical, and chemical industries employ a range of
heterogeneous catalysts to optimize the conversion of raw materials into products, achieving
this with minimal energy expenditure and reduced processing time. Resource scarcity and
disposal issues with low-activity catalysts pose major global challenges. Fresh catalysts incur
high costs, and the Earth's supply of essential metals is limited. Landfilling of spent catalysts,
which contain valuable and expensive metals, is harmful to human health and the
environment. Recycling catalytic minerals reduces the need for new resources, aiding in
resource conservation.
Conventional recovery methods employed at the commercial level, namely pyrometallurgy
and hydrometallurgy, are effective but exhibit considerable drawbacks, including high energy
demands and notable environmental impacts. Despite the availability of numerous
environmentally friendly techniques for metal recovery, their implementation remains
inconsistent. Organic acids are considered more environmentally friendly and cost-effective
compared to inorganic acids for the extraction of precious metals. Crude spent catalysts
contain trace amounts of valuable metals, such as 0.21 wt.% platinum and 0.25 wt.% rhenium,
and the primary objective is the recovery of these metals using organic acids. A 1M solution
of tartaric acid achieved over 90% platinum extraction from spent catalysts within 24 hours at
80°C. In comparison, organic acid-based hydrometallurgy exhibits significant potential for the
recovery of precious metals from spent catalysts.

The increasing prevalence of antimicrobial resistance is challenging the global healthcare system (1). The overuse and inappropriate use of antibiotics have resulted in pathogens with multi-drug resistance, leading the world to a pre-antibiotic era (2,3).

Therefore, the objective of this work is to develop an innovative drug delivery vehicle capable of addressing multidrug-resistant bacterial infections by converting them into an active support. To do this, we have encapsulated silver or gold metallic nanoparticles (MNP) in cross-linked lysozyme crystals. These crystals-composites of proteins and MNPs will behave as release vehicles capable of dealing with infections thanks to their dual composition and the control of the release rate by the degree of cross-linking of the crystals. We anticipate that this synergistic antimicrobial material may be an excellent strategy to combat biofilm formation.

To obtain this material, we followed a bottom-up protocol in which MNPs were firstly obtained in a peptide hydrogel of Fmoc-MF, which contains specific interaction sites with the MNPs to increase their stability during crystallization step. These metallogels were subsequently used as crystallization media to obtain lysozyme (Lzm) crystals. Composite Lzm@MNP crystals were later cross-linked at different degrees to control their dissolution rate.

Herein, we present a proof of concept of a novel active compounds’ delivery vehicle, in which the vehicle and itscargo have an active and remedial role.

Introduction:

This study presents the synthesis and characterization of a new metal–organic framework (MOF) incorporating cobalt(II) and 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide (odabco), namely [Co₂(H₂O)(NO₃)(odabco)₅](NO₃)₃. The anion substitution reaction in the framework has been studied, and the adsorption selectivity and reversibility of the iodide ions with this compound have been investigated.

Methods:

Synthesis: A mixture of Co(NO₃)₂·6H₂O (0.10 mmol) and odabco·3H₂O₂ (0.30 mmol) was prepared in a glass vial. The mixture was dispersed in a solution of DMF (5.0 ml), water (0.4 ml), and nitric acid (25 μl, 62%). The mixture was kept at 70°C for 72 hours. The crystal structure of the compound was confirmed using powder X-ray diffraction (PXRD) analysis. The chemical purity of the sample was verified using CHN analysis, infrared (IR) spectroscopy, and thermogravimetric analysis (TGA).

Ion exchange was studied using capillary zone electrophoresis (CZE). The iodide positions within the porous adsorbent were determined by single-crystal XRD. The structural integrity of the samples was verified using XRD and other methods.

Results:

The cationic coordination network was found to exhibit a high affinity for iodide, and the degree of substitution of the guest nitrates by iodides was 75%. The iodide positions were directly determined by a single-crystal XRD method within an anion-exchanged adduct, [Co₂(H₂O)(NO₃)(odabco)₅]I₂(NO₃)·1.85H₂O. The adsorption of iodide is selective and reversible. The iodide anions occupied specific positions within the network, stabilized by the aliphatic core of the odabco ligands. The incorporation of iodide into the pore structure stabilizes it and has the potential to effectively remove iodide from solutions.

Conclusions:

This study emphasizes the significance of MOFs for addressing challenges related to selective ion sorption and has potential applications in environmental management and health protection. Further research into similar systems and modifications may lead to the development of improved adsorbent materials for removing ions from solutions.

Introduction

Capturing CO₂ from the atmosphere represents a key challenge, since CO₂ has been recognized as the primary anthropogenic greenhouse contributor to the increase of earth’s average temperature. Metal- Organic Frameworks (MOFs) given their porosity and versatility are considered excellent candidates for gas adsorptive separation process. We reported herein a new synthetic protocol to obtain an improvement of the BET surface area of the [Co(trz₂An)]n·3H₂O MOF, where the ultra-microporosity and the presence of a ligand bearing two triazole pendant arms are fundamental in the CO₂ uptake.

Material and Methods

[Co(trz₂An)]n·3H₂O (Co_MOF’) has been synthesized optimizing the synthetic procedure reported in the literature for Co_MOF[1]. A mixture of CoCl₂·6H₂O and trz₂Anhilate ligand in a 1:1 stoichiometric ratio, via a hydrothermal reaction, was heated at 130°C for 48 hours. The dark brown rectangular crystals, suitable for a single X-ray diffraction study, were washed three times by using an aqueous aqueous solution (pH=5) in order to solubilize and remove the Co(OH)₂ obtained during the reaction. FT-IR and BET (Brunauer–Emmett–Teller) measurements were performed to compare the surface area values of Co_MOF and Co_MOF’_.

Results

The BET surface area of Co_MOF, determined with a high-pressure gravimetric analyzer employing CO₂, showed a value of 431 m²/g. Advanced characterization of Co_MOF via FT-IR spectroscopy revealed a peak at 3632 cm^-1, which could be assigned to the presence of Co(OH)₂. The new synthetic protocol allowed us to remove the Co(OH)_2, leading to the presence of Co_MOF’, which exhibited a BET value of 616 m²/g (almost 30% of the pristine value).

Conclusions

The optimized synthetic protocol represents a challenging strategy to obtain novel MOFs with different M^II eco-friendly transition metal ions with different improved sorption properties and selectivities toward CO₂.

Introduction

Due to the attention toward global warming, the current research is focusing on green fuels obtained by the reduction of captured CO₂ (e-fuels). A prominent example of these e-fuels is methane. Ni-based catalysts are among the most investigated systems for CO₂ methanation. Ni is often paired with a promoter, like CeO₂. In this work, composite catalysts consisting of a NiO and NiO/CeO₂ active phase dispersed on mesostructured silica (SBA-15) are presented, which, using a support, should allow us to reach a high activity with a reduced amount of the active phase.

Methods

To obtain NiO- and NiO/CeO₂-based nanocomposites, two different impregnation approaches were used: two-solvent (TS) impregnation and impregnation based on a self-combustion (SC) reaction. The NiO-based catalysts were obtained with a loading of 4.5%; the NiO/CeO₂-based catalysts were obtained using a 1:1 Ni:Ce molar ratio. To determine their structural and morphological properties, the catalysts were characterized with small-angle (SA-) and wide-angle (WA-) XRD (X-ray diffraction), TEM (transmission electron microscopy), and nitrogen physisorption and tested for CO₂ methanation.

Results and discussion

WA-XRD shows that the composites obtained with SC do not feature a diffraction peak, suggesting that NiO and CeO₂ are deposited into the mesopores as ultra-small nanoparticles. On the other hand, the composites obtained with TS impregnation show broad but visible crystal reflections attributed to both NiO and CeO₂, indicating that the active phase has crystallized, forming larger nanoparticles. This finding is also confirmed by the TEM micrographs, which for the SC composites do not show the presence of any visible particles outside the mesopores; the TS systems, conversely, show visibly darker nanoparticles dispersed over the support. The catalytic tests show a positive effect of CeO₂ on performance; furthermore, the catalysts obtained with SC impregnation show a higher CO₂ conversion, presumably due to the higher dispersion of the active phase obtained with this approach.