ULTRASOUND-ASSISTED EXTRACTION IN DELIGNIFICATION PROCESS TO OBTAIN HIGH PURITY CELLULOSE
Jia Jun Poon, Mei Ching Tan, Peck Loo Kiew
Abstract
The effect of ultrasound-assisted extraction (UAE) on the delignification of kapok fiber to obtain high purity cellulose was studied. Lignin from lignocellulosic material is usually removed by the sodium chlorite solvent extraction method. Although this method can obtain high purity cellulose, it requires 9 h of treatment. Ultrasound sonication was introduced to reduce the treatment time and improve cellulose purity. Kapok fiber treated with UAE at 70% sonication power, with the frequency of 53 kHz, for 20 min at 40 C, allowed obtaining cellulose with similar purity to that achieved by the conventional method, after it underwent the UAE delignification process for three times. Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) were performed to analyse the characteristics and purity of treated kapok cellulose, respectively. The results showed that delignification by UAE, using lower operating temperatures and shorter treatment time, was much more effective compared to the conventional method.