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This study aimed to develop four adsorbents, neat and activated, from the cardoon leaves and stems. The developed adsorbents were first analyzed to determine the surface acid–base properties using Boehm’s method, pH at zero charge point, iodine and methylene blue values, and moisture, ash, and fixed carbon contents. They were also characterized by scanning electron microscopy coupled with energy-dispersive X-ray analysis, X-ray diffraction, Fourier transform infrared absorption spectroscopy, thermogravimetric analysis, and inductively coupled plasma atomic emission spectroscopy. After that, these adsorbents were applied for adsorption of an organic dye “brilliant green” (BG), and the effect of various parameters on the adsorption efficiency was evaluated. The obtained results revealed the differences between the adsorbents derived from the neat cardoon leaves and stems and their activated carbon in terms of properties and BG adsorption efficiency.

In this research, the solid-state method was utilized to synthesize LaFeO3 powders, with La2O3 and Fe2O3 being employed as precursor materials. The prepared samples were calcined at different temperatures 800°C, 900°C, 1000°C, 1100°C, 1200°C and 1300°C for 4h to study phase stability. The thermal effect on structural and morphological properties was reported. The X-ray diffraction results confirmed the pure phase in its orthorhombic configuration at 1200°C and 1300°C, which was confirmed by Rietveld's analysis. Scanning electron microscopy coupled with Energy-dispersive X-ray spectroscopy was employed to analyze the surface morphology and compositional characteristics. In addition, the samples were analyzed by Fourier Transform Infrared Spectroscopy. The thermal behavior of the product was investigated through the utilization of thermogravimetric analysis. [ABSTRACT FROM AUTHOR]

The main interest in the valorization of vegetable wastes is due to the peculiarity of their chemical composition in substances that present important properties. Among these substances, antioxidants could replace those industrially manufactured. In the present study, three solvents of different polarities (hexane, ethanol, and water) were applied for the extraction of phenolic compounds from Cynara cardunculus L. waste using two extraction methods: Soxhlet Extraction (SE) and Ultrasonic-Assisted Extraction (UAE). The obtained extracts were then characterized by Fourier-Transform Infrared (FTIR) spectroscopy and spectrophotometric determination of Total Phenolics (TPC), Total Flavonoids (TFC), and Condensed Tannins (CT). Total Antioxidant Capacity (TAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of ethanol and water extracts of leaves and stems were also evaluated. High extraction yields were obtained by UAE. Water extracts had high yield regardless of the technique used for leaves and stems, and these extracts showed high TAC of 534.72 ± 3.83 mg AAE/g FM for leaves and 215.70 ± 8.87 mg AAE/g FM (mg of ascorbic acid equivalent per g of FM) for stems, and IC50 of 2077.491 μg/mL for leaves and 1248.185 μg/mL for stems. We explain the latter by the high total phenolic contents (TPCs), which reach 579.375 ± 3.662 mg GAE/g FM (mg of gallic acid equivalents per g of fresh matter) for leaves and 264.906 ± 3.500 mg GAE/g FM for stems. These results confirmed that the leaves and stems of the studied cardoon waste were, indeed, interesting sources of natural antioxidants. [ABSTRACT FROM AUTHOR]