ABSTRACT

During the extraction of fibers from the bast of A. venetum, there is an issue of the existence of undesirable macromolecules, for example, pectins. Separation of these compounds is mostly done by pretreatment with H₂SO₄ and then by NaOH boiling in the traditional method (Fiber-C). The use of Sulfuric acid for pretreatment may cause harm to both fibers and the environment. In order to overcome these limitations, attempts were made to find a new pretreatment (Fiber-N) method. The hypothetical premise of the new pretreatment strategy dependent on the use of Al₂(SO₄)₃ is presented. Four model solutions were investigated using a method of measuring zeta potential. Furthermore, fibers obtained by pretreatment methods along with the raw fibers of A. venetum had been characterized by Electron spin resonance spectroscopy (ESR), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), and water retention value (WRV). Results showed that pure salts of Al₂(SO₄)₃ presented improved binding properties with the pectin and causes better swelling and eventually helps to remove pectin than other pretreatment processes. Ultimately, Donnan equilibrium, metal ion complex formation, and Gouy–Chapman–Stern (GCS) model were used to theoretically elucidate the discharging mechanism of pectin macromolecules from A. venetum in the presence of Al³⁺ ions during pretreatment.

摘要

在从A. venetum韧皮中提取纤维的过程中，存在一个问题，即存在不希望的大分子，例如果胶。这些化合物的分离主要通过用 H ₂ SO ₄预处理，然后在传统方法（Fiber-C）中通过 NaOH 煮沸来完成。使用硫酸进行预处理可能会对纤维和环境造成危害。为了克服这些限制，人们尝试寻找一种新的预处理（Fiber-N）方法。新预处理策略的假设前提取决于使用 Al ₂ (SO ₄ ) ₃被呈现。使用测量 zeta 电位的方法研究了四种模型解决方案。此外，通过电子自旋共振光谱 (ESR)、X 射线衍射 (XRD)、扫描电子显微镜 (SEM)、傅里叶变换红外光谱 ( FT- IR) 和保水值 (WRV)。结果表明，Al ₂ (SO ₄ ) _3的纯盐与其他预处理工艺相比，其与果胶的结合性能得到改善并导致更好的溶胀，最终有助于去除果胶。最后，利用Donnan 平衡、金属离子络合物形成和Gouy-Chapman-Stern (GCS) 模型从理论上阐明了在Al ³⁺离子存在下预处理过程中A. venetum中果胶大分子的放电机制。