Lignin and Cellulose Extraction from Vietnam’s Rice Straw Using Ultrasound-Assisted Alkaline Treatment Method

Ngo Dinh Vu,Hung Viet Nguyen,Hang Thi Tran,Cuong Duc Vu,Nhi Dinh Bui

doi:10.1155/2017/1063695

Ngo Dinh Vu, Hung Viet Nguyen + Show 3 more

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https://doi.org/10.1155/2017/1063695

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Abstract

The process of cellulose and lignin extraction from Vietnam’s rice straw without paraffin pretreatment was proposed to improve economic efficiency and reduce environmental pollution. Treatment of the rice straw with ultrasonic irradiation for 30 min increased yields of lignin separation from 72.8% to 84.7%. In addition, the extraction time was reduced from 2.5 h to 1.5 h when combined with ultrasonic irradiation for the same extraction yields. Results from modern analytical methods of FT-IR, SEM, EDX, TG-DTA, and GC-MS indicated that lignin obtained by ultrasound-assisted alkaline treatment method had a high purity and showed a higher molecular weight than that of lignin extracted from rice straw without ultrasonic irradiation. The lignin and cellulose which were extracted from rice straw showed higher thermal stability with 5% degradation at a temperature of over 230°C. The ultrasonic-assisted alkaline extraction method was recommended for lignin and cellulose extraction from Vietnam’s rice straw.

Highlights

As the world’s most abundant renewable resource, lignocellulosic biomass has been acknowledged for potential use to produce chemicals and biomaterials
Fiber size of cellulose was determined by scanning electron microscope (SEM: JEOL, Japan); surface tension of lignin was determined on the CAM 200 (KSV Instructions, Finland)
The rice straw is a dense block (Figures 2(a) and 2(b)), but the bonds between lignin, hemicellulose, cellulose, and other components have been separated after alkaline treatment at 90∘C for 1.5 hours and ultrasonic irradiation for 30 min

Summary

Introduction

As the world’s most abundant renewable resource, lignocellulosic biomass has been acknowledged for potential use to produce chemicals and biomaterials. The main methods of the extraction of lignin and cellulose from different sources historically explored are hydrothermal, acidic, alkaline, wet oxidation, ammonia fiber explosion, organosolv, and, most recently, ionic liquid pretreatment methods (which were reviewed elsewhere) [13,14,15]. These extraction methods are expensive and energy intensive and utilize chemicals which require special disposal, handling, or production methods. This paper gives an overview on investigation of the extraction method of lignin and cellulose from Vietnam’s rice straw using the combination of ultrasound irradiation and chemical method under high temperature and alkaline concentration to reduce extraction time. The properties of obtained lignin and cellulose were evaluated

Experimental Section

Results and Discussion

Conclusion