Microalgae serve as efficient biological platforms for CO2 capture, and their catalytic pyrolysis offers a sustainable route to convert renewable carbon into a hydrocarbon-rich bio-oil precursor, with catalysts playing a key role in upgrading pyrolysis vapors and improving fuel quality. Layered materials, a promising class of solid acid catalysts, are expected to enhance the deoxygenation of bio-oil, facilitating its conversion into hydrocarbon-rich bio-oil precursors. In this context, the innovative contribution of this work lies in exploring the potential of four catalysts, Ni-Al layered double hydroxide (NALH), aluminum-containing layered magadiite (ALMG), titanium-containing layered magadiite (TIMG), and potassium hexaniobate (KHEX), on the pyrolysis vapors of Chlorella sp. microalgae. Experiments were conducted in an analytical pyrolyzer (Py-GC/MS) at 500 °C using a 5:1 catalyst-to-biomass ratio. The pyrolysis of Chlorella sp. microalgae primarily yielded oxygen-containing compounds (40.1%). Catalytic Py-GC/MS analysis revealed that layered materials are effective for converting microalgae into renewable hydrocarbons and for reducing the content of oxygenated compounds in upgraded condensable volatile products. Among the catalysts, TIMG exhibited the highest selectivity for aromatic hydrocarbons (2.2-fold increase) and the highest hydrocarbon recovery (73.2%). However, when the focus shifted to maximizing the degree of deoxygenation (88.4%) and selectivity for C5-C12 hydrocarbons (87.6%), NALH proved to be the most effective catalyst. The results demonstrate that layered materials are promising catalysts for converting microalgae into hydrocarbon-rich bio-oil, offering a sustainable, renewable alternative to petroleum-derived fuels and supporting bioeconomy development.
The transition toward low-carbon fuels demands efficient routes for converting renewable feedstocks into drop-in hydrocarbons. In this work, we report an alternative, metal-free photodecarboxylative protocol for the production of hydrocarbons within the Sustainable Aviation Fuel (SAF) range, starting from N-hydroxyphthalimide-derived redox-active esters obtained from C10-C18 fatty acids. The methodology relies on the in situ formation of an electron donor-acceptor (EDA) complex between the redox-active ester and the Hantzsch ester, which simultaneously acts as a hydrogen atom donor and photochemical activator, thereby eliminating the need for metal catalysts and molecular hydrogen. Under visible-light irradiation, at ambient temperature and atmospheric pressure, using isopropyl alcohol as solvent, saturated substrates achieved conversions exceeding 99% and afforded the corresponding n-alkanes (Cn-1) in yields of up to 83%. Chain-length variation influenced the overall efficiency, providing C9-C17 alkanes in yields ranging from 52 to 83%. Unsaturated C18 substrates furnished the corresponding olefins in moderate yields (up to 48%). The one-pot strategy maintained conversions above 90% and enabled the direct application of the protocol to a range of real lipidic biomasses, delivering overall yields between 31 and 79%. The protocol operates under mild conditions, tolerates open-air atmosphere, and can be driven by solar irradiation, representing a promising alternative to conventional SAF production pathways.
The presence of antibiotics in aquatic environments poses risks to public health and ecosystem, particularly due to the promotion of antimicrobial resistance. Rifampicin (RIF), a chemically stable and biologically active antibiotic, is increasingly detected in wastewater streams and remains insufficiently removed by conventional treatment processes. In this study, cellulosic residue based reduced graphene oxide (RC-rGO) was synthesized from cotton textile waste via a simplified ferrocene-assisted thermal carbonization route and evaluated as an adsorbent for RIF removal from aqueous solutions. Structural and surface characterization (XRD, FTIR, Raman spectroscopy, HRTEM, BET analysis, and zeta potential measurements) confirmed with a surface area of 208 m2 g⁻1 and average pore diameter of 3.16 nm. The resulting turbostratic graphene exhibits heterogeneous surface chemistry and mesoporosity favorable for adsorption for RIF, achieving > 95
Context. Gas giant planets orbiting low-mass stars (T-eff less than or similar to 4600 K) are uncommon outcomes of planet formation. Increasing the sample of well-characterised giants around early M dwarfs will enable population-level studies of their properties, offering valuable insights into their formation and evolutionary histories. Aims. We aim to confirm and characterise giant exoplanets transiting M dwarfs identified by the TESS mission. To this end, we have started the Gas giAnts Transiting 1Ow-mass Stars (GATOS) programme within the NIRPS guaranteed time observations (GTO). Methods. High-resolution spectroscopic data were obtained in the optical and near-infrared (nIR), combining HARPS and NIRPS. We derived radial velocities (RVs) via the cross-correlation function and implemented a novel post-processing procedure to further mitigate telluric contamination in the nIR. The resulting RVs were jointly fit with TESS and ground-based photometry to derive the orbital and physical parameters of the systems. Results. We present the GATOS programme and its first results. We confirm two gas giants transiting the low-mass stars TOI-3288 A (K9V, T-eff = 3933 +/- 48 K) and TOI-4666 (M2.5V, T-eff = 3512 +/- 36 K). TOI-3288 A hosts a hot Jupiter with a mass of 2.11 +/- 0.08 M-Jup and a radius of 1.00 +/- 0.03 R-Jup, with an orbital period of 1.43 days (T-eq = 1059 +/- 20 K). TOI-4666 hosts a 0.70 +/- 0.06 M-Jup warm Jupiter (T-eq = 713 +/- 14 K) with a radius of 1.11 +/- 0.04 R-Jup, with an orbital period of 2.91 days. At a population level, we identify a decrease in planetary mass with spectral type, whereby late M dwarfs host less massive giant planets than early M dwarfs. More massive gas giants that deviate from this trend are preferentially hosted by more metal-rich stars. Furthermore, we find an increased binarity fraction among low-mass stars hosting gas giants, which may play a role in enhancing giant planet formation around low-mass stars. Conclusions. These mass characterisations contribute to the growing catalogue of well-defined giant exoplanets around low-mass stars. The observed population trends agree with theoretical predictions, whereby higher metallicity can compensate for lower disc masses, and wide binary systems may influence planet formation and migration through Kozai-Lidov cycles or disc instabilities.
This study aimed to evaluate the effects of atenolol administration on salivary gland structure, redox status, and sialochemical composition in male rats. Male Wistar rats (Rattus norvegicus), aged 90 days, were randomly assigned to two groups: a control group receiving distilled water and an atenolol-treated group receiving 20 mg/kg/day by orogastric gavage for 30 days. On day 31, the animals were anesthetized, saliva was collected, and the parotid, submandibular, and sublingual glands were harvested for oxidative, morphometric, histopathological, and biochemical analyses. The results showed no systemic changes in plasma parameters. However, atenolol administration was associated with local redox imbalance in salivary glands, accompanied by alterations in salivary biochemistry, including reduced antioxidant capacity and increased pro-oxidant markers (lipid peroxidation and protein carbonylation). Morphological analysis revealed acinar atrophy in all glands, as well as reduced stroma and collagen fibers in the parotid and submandibular glands. Sialochemical analysis demonstrated decreased levels of total protein, mucin, and phosphate, along with increased calcium concentration. Atenolol use was associated with sialochemical disturbances and structural alterations in salivary glands, accompanied by inflammatory cell presence and changes in oxidative stress markers in both tissue and saliva, suggesting potential implications for oral health.
