College of Bioresources Chemical and Materials Engineering, Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry, Ministry of Education, Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry and Technology, College of Mechanical and Electrical Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, PR China; Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, PR China.
College of Bioresources Chemical and Materials Engineering, Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry, Ministry of Education, Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry and Technology, College of Mechanical and Electrical Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, PR China.
Int J Biol Macromol. 2023 Jun 15;240:124437. doi: 10.1016/j.ijbiomac.2023.124437. Epub 2023 Apr 14.
Natural polysaccharide hydrogel, exemplified by chitosan‑sodium alginate (CS-SA), has been prevailing in adsorption of chromium (III) (Cr(III)) containing contaminant. However, the traditional desorption of CS-SA-Cr(III) to recycle the adsorbent faces the problems including chemical desorbents secondary pollution, resource waste of the terminal CS-SA adsorbents, and tedious work of reusing the desorbed Cr(III). Herein, the adsorption product, CS-SA-Cr(III) gel, was degraded to CS/SA/Cr(III) sol and applied in leather re-tanning and filling processes directly. To achieve this goal, three degradation methods were used to transform the gel to sol. Due to the excellent overall performance of the CS/SA/Cr(III)-HMD sol (obtained by the hydrothermal-mechanical degradation method for 4 h (HMD)), including wide size and distribution range, moderate viscosity (54 ± 3.1 mPa·s), high electronegativity (-38.6 ± 5.8 mV), and good stability, the resultant leather after re-tanning and filling by the sol achieved fascinating properties such as good thermal stability (T, 116.8 ± 1.8 °C; T, 94.2 ± 1.7 °C), mechanical performance (tensile strength, 6.9 ± 0.52 MPa; elongation at break, 95 ± 3.0 %), and superduper thickening rate (31.8 %). Moreover, the mechanism of good re-tanning and filling effects was deciphered. Therefore, this work intends to overcome the limitation of traditional desorption technology and further realizes the high-valued application of the exhausted CS-SA-Cr(III) in leather re-tanning and filling processes.
天然多糖水凝胶，以壳聚糖-海藻酸钠（CS-SA）为例，在吸附含铬（III）（Cr(III)）的污染物方面具有优势。然而，传统的 CS-SA-Cr(III) 解吸方法存在化学解吸剂二次污染、CS-SA 终端吸附剂资源浪费以及解吸 Cr(III) 再利用繁琐等问题。在此，将吸附产物 CS-SA-Cr(III) 凝胶降解为 CS/SA/Cr(III) 溶胶，并直接应用于皮革鞣制和填充过程。为了实现这一目标，使用了三种降解方法将凝胶转化为溶胶。由于 CS/SA/Cr(III)-HMD 溶胶（通过水热-机械降解 4 小时（HMD）获得）具有出色的整体性能，包括较宽的粒径和分布范围、适中的粘度（54±3.1 mPa·s）、高电负性（-38.6±5.8 mV）和良好的稳定性，用该溶胶鞣制和填充后的皮革具有出色的性能，如良好的热稳定性（T，116.8±1.8°C；T，94.2±1.7°C）、机械性能（拉伸强度，6.9±0.52 MPa；断裂伸长率，95±3.0%）和超高增厚率（31.8%）。此外，还揭示了良好鞣制和填充效果的机制。因此，这项工作旨在克服传统解吸技术的局限性，并进一步实现废弃的 CS-SA-Cr(III) 在皮革鞣制和填充过程中的高附加值应用。
