In recent years, the focus on environmental sustainability and circular economy has encouraged the reutilization of plant residues. This work aimed at evaluating the potential of discarded yerba mate (DYM) as a source of cellulose fibers suitable to retain low biodegradability emerging contaminants, such as dyes. In addition, we aimed at testing whether the inclusion of silver nanoparticles within those fibers could result in a novel nanocomposite with antimicrobial properties. The raw material (DYM) and the cellulose fibers were characterized according to TAPPI standards. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and tensile strength assessment were conducted. The cellulose content of the DYM was 46.61%. The XRD analysis revealed an increase in cellulose crystallinity index from 19% in the raw material to 60% after cellulose extraction treatments. Cellulose fibers adsorbed about 80–90% of the dyes tested (crystal violet, CV; methylene blue, MB; and safranin, S) at a concentration of 20 mg/L. The adsorption efficiency of the nanocomposite was somewhat lower than that of the fibers alone, while its ability to immobilize and cells was higher. Due to these features, the nanocomposite here described could be useful to obtain, in the future, a simple filtering device which could provide safer water at domestic level to periurban settlers with no access to potable water sources.

中文翻译：

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废弃的马黛茶作为纤维素纤维的来源，在饮用水净化方面具有广阔的应用前景

近年来，对环境可持续性和循环经济的关注鼓励了植物残留物的再利用。这项工作旨在评估废弃马黛茶 (DYM) 作为纤维素纤维来源的潜力，适合保留低生物降解性的新兴污染物，例如染料。此外，我们的目的是测试这些纤维中包含银纳米颗粒是否可以产生具有抗菌特性的新型纳米复合材料。原材料 (DYM) 和纤维素纤维根据 TAPPI 标准进行表征。进行了傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、热重分析（TGA）和拉伸强度评估。DYM的纤维素含量为46.61%。XRD 分析表明，经过纤维素提取处理后，纤维素结晶度指数从原材料中的 19% 增加到 60%。纤维素纤维吸附浓度为 20 mg/L 的约 80-90% 的测试染料（结晶紫，CV；亚甲蓝，MB；和番红，S）。纳米复合材料的吸附效率略低于单独的纤维，但其固定细胞的能力较高。由于这些特征，这里描述的纳米复合材料在未来可能有助于获得一种简单的过滤装置，该装置可以为无法获得饮用水源的城郊定居者提供更安全的家庭用水。