Different Sequential Chemical Treatments Used to Obtain Bleached Cellulose from Orange Bagasse

ABSTRACT

The development of efficient pretreatments is widely used in biobased products aiming to add value to the residue. In this study, orange bagasse is investigated for cellulose extraction under moderate chemical sequential extraction conditions. Three pretreatments are evaluated: alkaline treatment, organosolv, and residue insoluble alcohol. Then, all pretreated samples are bleached. The results are analyzed by chemical composition, Fourier transformed infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. In general, similar results are observed for all bleaching samples, independently of the pretreatment. A similar cellulose amount is observed among the samples. When compared only to the pretreatments, alkaline shows to be a more effective way of presenting a higher crystallinity index. Hemicellulose and lignin are mostly removed after pretreatment. FTIR and XRD indicated that the pretreatment seems to be more effective in the first step. TG curves presented a more homogeneous pattern due to cellulose removal showing three steps for pre-treatment and two steps for bleached samples. The obtained cellulose has numerous potential applications, and a suitable route can be selected according to available reagents.

高效预处理技术的发展广泛应用于生物基产品中, 旨在为残留物增值. 在本研究中, 研究了在中等化学顺序提取条件下橘子蔗渣对纤维素的提取. 评估了三种预处理: 碱处理、有机溶剂和残渣不溶醇. 之后, 将所有预处理样品漂白. 通过化学成分、傅里叶变换红外光谱、射线衍射和热重分析对结果进行了分析. 一般而言, 所有漂白样品的结果相似, 与预处理无关. 观察到样品中的纤维素含量相似. 仅与预处理相比, 碱性是呈现更高结晶指数的更有效方法。预处理后, 半纤维素和木质素大部分被去除. FTIR和XRD表明, 第一步预处理似乎更有效. 由于纤维素的去除, TG曲线呈现出更均匀的模式, 显示了三个预处理步骤和两个漂白样品步骤. 所获得的纤维素具有许多潜在的应用, 并且可以根据可用试剂选择合适的路线.

KEYWORDS:

• Orange bagasse
• chemical treatment
• waste bleaching
• natural fibers
• cellulosic
• green solvents

关键词:

• 橙色蔗渣
• 化学处理
• 废物漂白
• 天然纤维
• 纤维素
• 绿色溶剂

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge the financial support by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP-Brazil), Paulo Henrique Fernandes Pereira (Grant n° 2015/10386-9), Luana Lima Fernandes (Grant n° 2017/19530-0), and Liziane B. Ubirajara Santos (Grant n°2016/16168-6).