A simple process of isolation microcrystalline cellulose using ultrasonic irradiation

Abstract

MicroCrystalline Cellulose (MCC) is commonly produced from wood pulp, cotton linters or any other fiber sources by thermal hydrolysis using mineral acids. This is a time-consuming process and high energy consumption resulting in high economic costs and environmental impact. From this basis, MCC was isolated from bacterial cellulose (BC) using ultrasonic irradiation. The effect of irradiation time and different type of aqueous solution at constant temperature, power, and frequency of the ultrasound on the chemical structure, crystallinity index (CrI), thermal property, and surface morphology of isolated MCC were examined. To evaluate of partial depolymerization rate in the process of isolation MCC, a simple equation model will be developed through the correlation between CrI with irradiation times. The results indicate that the ultrasonic treatment in the mixture of water/ethanol (50% w/w) induced increase of the crystallinity, at which the minimum hydrodynamic diameter was 1.56 μm corresponding the maximum CrI obtained was 73.6% in the 120 min of irradiation time. Chemical structures analysis demonstrated that modifications of native BC structure into micro-sized MCC remained unchanged during the treatment and the best predictive model obtained is first-order reaction as depicted by the fit (R² = 0.9911).

Graphical Abstract

Keywords:

• Bacterial cellulose microcrystals
• amorphous regions
• ultrasonic irradiation
• crystallinity index
• kinetic depolymerization model

Acknowledgments

We gratefully acknowledge funding from the Engineering Faculty Universitas Sultan Agung Tirtayasa (UNTIRTA) Indonesia, under project hibah internal fakultas 2018.