关键词: 罗布麻, 脱胶, 染色, 一浴法, 活性染料, 微波预处理, 响应面法

Abstract:

Objective Conventional two-bath/two-step sequence, namely alkaline degumming followed by reactive dyeing, employed for Apocynum venetum, is featured by high water and energy consumption and heavy effluent loads. Herein, a one-bath integrated degumming-dyeing protocol was developed to achieve more efficient processing of Apocynum venetum.

Method Three different types of reactive dyes, namely, M-type, BES-type and Cibacron-type, were used as dyes in one-bath process, and the reactive dye suitable for the process was screened out. Response Surface Methodology (RSM) optimization was then used to optimize the one-bath process. To evaluate the effectiveness of the proposed new strategy, the one-bath process was compared with the two-bath process in terms of water consumption, electricity consumption and chemical oxygen demand (COD) of wastewater. Finally, the physical and chemical properties of the treated Apocynum venetum were characterized by Fourier Transform Infrared(FT-IR), Scanning Electron Microscopy(SEM) and X-Ray Diffraction(XRD).

Results Among the three reactive dyes evaluated, M-type demonstrated the best performance in the one-bath process. Optimization via Response Surface Methodology yielded the following conditions: dye concentration 1% (o.w.f), enzyme 1.75 g/L, degumming at 80 ℃, H₂O₂ (30%) 25% (o.w.f), and dyeing at 60 ℃ for 60 min. These parameters resulted in a residual gum rate of 6.2%, a high K/S value of 3.38, and excellent wash fastness (grade 4-5). The one-bath process showed significant advantages over the conventional two-bath method in reducing water consumption by 38.7%, energy use by 42.5%, processing time by 12.4%, and wastewater COD by 51.8%. Furthermore, the treated fibers exhibited superior mechanical properties, with single-fiber breaking strength increasing to 16.76 cN from 13.05 cN. Physicochemical characterization confirmed effective gum removal and structural changes. FT-IR indicated removal of non-cellulosic components, SEM revealed smoother fiber surfaces, and XRD showed increased crystallinity index from 77.37% to 92.27%.

Conclusion This research successfully established a one-bath degumming and dyeing process for Apocynum venetum fiber using M-type reactive dyes. This integrated approach eliminates intermediate steps, significantly reducing resource consumption, processing time, and environmental impact. The optimized process not only ensured efficient gum removal and high dyeing quality but also remarkably improved the fiber's tensile strength. These findings were corroborated by multiple analytical techniques, confirming the effectiveness and potential of this method as a sustainable and economically viable alternative for valorizing Apocynum venetum fiber.

Key words: Apocynum venetum, degumming, dyeing, one-bath process, reactive dye, microwave pretreatment, response surface methodology