Mourak Abdellah, Hajjaji Mohamed, Alagui Abdelhakim
Laboratoire Physico-Chimie Des Matériaux Et Environnement, UCA Faculté Des Sciences Semlalia, Université Cadi Ayyad, Av. Pce My Abdellah , B.P. 2390, 40001, Marrakech, Morocco.
Sci Rep. 2025 Aug 12;15(1):29463. doi: 10.1038/s41598-025-14662-0.
The microstructure of beads composed of 50 mass% α-chitosan and either montmorillonite, a clay minerals mixture (illite, pyrophyllite, and kaolinite), or palygorskite was investigated using X-ray diffraction and scanning electron microscopy. Moreover, the kinetics of water adsorption and desorption by the beads were studied at temperatures ranging from 25 to 45 °C. Adsorption-desorption cycles were conducted to assess the beads performance. The findings revealed that chitosan and montmorillonite were linked by electrostatic forces, with no intercalation of chitosan observed. Additionally, attractive electrostatic forces were noted between the clay minerals assemblage and chitosan. Conversely, repulsive electrostatic forces occurred between chitosan and palygorskite, with the clay fibers acting as fillers. The study also showed that the maximal adsorption kinetic constants for montmorillonite-containing beads, palygorskite-containing beads, and chitosan beads were 13.6 × 10 s, 16.7 × 10 s, and 31 × 10 s, respectively. As for the beads composed of the clay minerals assemblage, the maximum adsorption kinetic constant was 2.8 × 10 mg s. Notably, high water adsorption capacities were measured for the beads consisting of palygorskite and the clay minerals assemblage (22% and 34% mass/mass, respectively). Regarding desorption kinetics, relatively high rate constants were determined for beads composed of montmorillonite and the clay minerals assemblage (38.6 × 10 s and 39 × 10 s, respectively). In addition, more than 90% of adsorbed water was released by all studied beads at 45 °C, and the adsorption/desorption performances of the beads were not significantly affected by the applied cycles.
使用X射线衍射和扫描电子显微镜研究了由50质量%的α-壳聚糖与蒙脱石、一种粘土矿物混合物（伊利石、叶蜡石和高岭石）或坡缕石组成的珠子的微观结构。此外，研究了这些珠子在25至45°C温度范围内的水吸附和解吸动力学。进行了吸附-解吸循环以评估珠子的性能。研究结果表明，壳聚糖和蒙脱石通过静电力相连，未观察到壳聚糖的插层现象。此外，在粘土矿物组合与壳聚糖之间也发现了有吸引力的静电力。相反，壳聚糖和坡缕石之间存在排斥性静电力，粘土纤维起到了填料的作用。该研究还表明，含蒙脱石珠子、含坡缕石珠子和壳聚糖珠子的最大吸附动力学常数分别为13.6×10⁻³ s⁻¹、16.7×10⁻³ s⁻¹和31×10⁻³ s⁻¹。至于由粘土矿物组合组成的珠子，最大吸附动力学常数为2.8×10⁻³ mg s⁻¹。值得注意的是，由坡缕石和粘土矿物组合组成的珠子具有较高的水吸附容量（分别为22%和34%质量/质量）。关于解吸动力学，由蒙脱石和粘土矿物组合组成的珠子具有相对较高的速率常数（分别为38.6×10⁻³ s⁻¹和39×10⁻³ s⁻¹）。此外，在45°C时，所有研究的珠子释放了超过90%的吸附水，并且珠子的吸附/解吸性能不受所施加循环的显著影响。
