ABSTRACT

Pomelo is cultivated worldwide due to its unique taste. Most of the pomelo peel is discarded, thus, wasting the beneficial ingredients contained in it. In order to effectively utilize these ingredients, a green and low-consumption method has been reported here to extract the cellulose nanofibrils (CNFs) from the pomelo peel by employing the sequential alkaline treatment, bleaching, acid hydrolysis, and ball milling. The results demonstrate that the impurities in the pomelo peel, such as hemicellulose and lignin, are gradually removed. The obtained CNFs still maintain their natural cellulose structure. The degree of crystallinity and thermal stability of CNFs are noted to be significantly improved as compared to the raw pomelo peel. The CNF diameter is observed to range between 6 and 47 nm. Compared with 10–17.5% NaOH/KOH and 60–65% HNO₃/H₂SO₄ used in previous studies, the developed method requires a low concentration of the alkali solution and bleaching agent. Further, the lemon juice, used as an acidolysis agent, is inexpensive and environmentally friendly. The ball milling purifies the CNFs and effectively reduces the size of CNFs without consuming a significant amount of energy. This study lays a foundation for an effective use of the agricultural solid waste based on pomelo peel.

摘要

柚子因其独特的味道而在世界范围内种植。大部分柚皮被丢弃，从而浪费了其中所含的有益成分。为了有效利用这些成分，本文报道了一种绿色、低消耗的方法，通过连续碱处理、漂白、酸水解和球磨从柚皮中提取纤维素纳米原纤维（CNFs）。结果表明，柚皮中的半纤维素、木质素等杂质逐渐被去除。获得的 CNFs 仍保持其天然纤维素结构。与生柚皮相比，CNF 的结晶度和热稳定性显着提高。观察到的 CNF 直径范围在 6 到 47 nm 之间。与 10–17.5% NaOH/KOH 和 60–65% HNO 相比₃ /H ₂ SO ₄在以前的研究中使用，开发的方法需要低浓度的碱溶液和漂白剂。此外，用作酸解剂的柠檬汁价格低廉且环保。球磨净化了 CNFs 并在不消耗大量能量的情况下有效地减小了 CNFs 的尺寸。本研究为有效利用以柚皮为原料的农业固体废弃物奠定了基础。