Marrubium vulgare L., Calendula arvensis (Vaill.) L. and Ajuga iva L. are Moroccan medicinal plants with diverse phytochemical profiles and established traditional uses. This study aimed to comparatively characterize the mineral composition, photosynthetic pigments, total phenolic, flavonoid contents, and antioxidant activity of these wild species collected from the Settat region of Morocco. Mineral ions were quantified by ion chromatography, while phenolic compounds, flavonoids, chlorophylls and carotenoids were determined using spectrophotometric methods. Antioxidant activity was assessed using the DPPH radical-scavenging assay. The species exhibited distinct mineral and phytochemical profiles. C. arvensis (Vaill.) L. had the highest chloride (155.57 ± 4.65 ppm), sulphate (53.02 ± 0.91 ppm), and carotenoid (0.0834 ± 0.0521 mg kg–1 DW) contents, whereas A. iva L. showed the highest phosphate (58.33 ± 0.13 ppm), nitrite (49.15 ± 0.01 ppm), chlorophyll a (0.150 ± 0.0591 mg kg–1 DW) and DPPH activity (135.87 ± 5.81 mg AAE kg–1 FW). M. vulgare L. contained the highest total phenolic (992.02 ± 38.94 mg GAE kg–1 FW) and flavonoid (2034.47 ± 81.00 mg QE kg–1 FW) contents. These findings provide a descriptive comparative framework of the biochemical composition of these species, which may inform future studies into their pharmacological potential.
In this recent study, Nannochloropsis microalgae biodiesel was produced through heterogeneous catalytic transesterification process using agro-wastes catalyst on silicon oxide support. The CaO/SiO2 catalyst was prepared by calcination of rice-husks and subsequent precipitation and re-calcination with calcium hydroxide powder at 750 ºC. The Nannochloropsis microalgae strains were cultured in a 10 L capacity, vertical-column photobioreactor with a glass-cylindrical vessel transparent column for easier penetration of light and extraction of lipids was carried out in a bio-based automatic Soxhlet extractor (model BFA-1S). The crystals’ structure, surface morphological characteristics and functional group analysis of the supported catalysts were evaluated by standard analytical techniques. The microalgae have a high lipid content of 48.15 ± 2.50. The CaO/SiO2 catalyst showed a high biodiesel yield of 97.15% and superior ester quality. This is attributed to its superior structural orientation, larger pores and excellent close-packed architecture, as confirmed by XRD and SEM analyses, leading to increased surface area, higher active-site density, enhanced mass-transfer kinetics and improved catalytic efficiency. Microalgae biodiesel produced using the CaO/SiO2 catalyst showed low free (0.004%) and total glycerine (0.015%) levels, per ASTM D6584. These values indicate efficient glyceride conversion, effective purification and high catalytic performance of the heterogeneous transesterification system. Interestingly, the catalyst can be reused up to the 6th cycle with desirable ester yield of 87.55% without any significant loss of activity due to creation of a more stable composite structure (Ca–O–Si bond) that maintains its integrity and minimizes the leaching of its active site. Finally, agro-wastes materials offer novel heterogeneous catalysts for cost-effective biodiesel production and a waste to wealth strategy towards circular economy and sustainable development.
Water hyacinth plant powder (WPP) prepared from mature, dried water hyacinth (Eichhornia crassipes) plant, found in various water bodies in Assam, India, was investigated to assess its ability as bioadsorbent to remove cadmium and nickel from aqueous solutions using adsorption process. WPP was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The maximum biosorption was found at pH 5.0 and 7.0 for the metal ions Cd(II) and Ni(II), respectively on WPP. In the batch study, 10 synthetic mediums containing 40, 50, 60 70 and 80 mg L–1 of the two toxic elements, Cd and Ni were treated with WPP. From the batch study, it was found that second-order kinetics is followed by both the metal (Cd and Ni) for the biosorption process and for the explanation of adsorption equilibrium data Langmuir model is suitable for both Cd(II) and Ni(II) biosorption on WPP. In the present study Langmuir monolayer capacity for Cd was observed to be 34.11 mg g–1 and 0.26 mg g–1 for Ni. These results indicated that WPP might be an effective adsorbent for treatment of water contaminated with cadmium and nickel.
A highly effective and fast processing method was reported for the preparation of several acridinedione derivatives using a catalytic amount of silica-containing MgZrO3 (SiO2:MgZrO3). The synthesized metal oxide material was characterized using FTIR, XRD, SEM-EDAX, TEM and BET surface area analysis. FTIR analysis confirmed the characteristic Mg–O vibrational band in the range of 600-400 cm–1, along with bands at 550 and 405 cm–1 attributed to Si–O and Zr–O stretching vibrations, respectively. XRD analysis revealed a well-defined crystalline structure consistent with JCPDS card No. 19-2936. SEM imaging demonstrated a uniform cubic surface morphology, while EDAX analysis confirmed the presence of Zr, Mg, Si and O, supporting the successful formation of the desired material. TEM images further revealed the morphological features of the material and the corresponding SAED pattern was consistent with the crystalline phases identified by XRD. The material exhibited a BET surface area of 103.25 cm2/g, which indicate a relatively high accessible surface area that may support its potential application in surface-mediated processes. Low catalytic loading of silica-containing MgZrO3 was found to be an economical and reusable catalyst for organic transformation. The obtained percentage yield of the product was good, with a cost-effective experimental setup and the final products were pure and facile. The catalyst can be reused several times without loss of product yield or activity.
In this study, a carbon black-doped europium oxide (Eu2O3) thick-film gas sensor was developed and systematically evaluated for CO2 sensing applications. The sensing layers were fabricated using a screen-printing technique, with Eu2O3 paste prepared with an organic binder, followed by the incorporation of carbon black at different doping concentrations (0.1-5 wt.%). The structural and compositional characteristics of the films were investigated using field-emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX), while their electrical properties were evaluated through current-voltage (I-V) measurements. Gas-sensing performance was investigated in a controlled chamber with CO2 concentrations ranging from 1000 to 5000 ppm. The results revealed that the carbon black incorporation significantly improved the microstructure of the sensing film by reducing particle agglomeration and generating a more porous, uniform morphology, thereby facilitating gas diffusion and charge transport. Among the tested samples, the sensor with 2 wt.% carbon black doping exhibited the best performance, achieving high linearity (97.66%) and enhanced sensitivity of 0.05327 mV/ppm compared with the undoped Eu2O3 sensor (0.01476 mV/ppm). The optimized sensor exhibited good repeatability, satisfactory stability, and reduced hysteresis during successive CO₂ exposure cycles. These improvements may be attributed to the formation of conductive pathways and the increased availability of active surface sites introduced by carbon black within the Eu2O3 matrix. The results establish carbon black-modified Eu2O3 thick films as promising candidates for room-temperature CO₂ gas sensing, with competitive sensing performance.
