Using modified rice husks for oil sorption

Abstract

In this thesis, different ways of delignifying rice husks were tested and a comparison on the basis of the oil sorption capacity using chemical and biological pretreatment of rice husks. Three chemical pretreatment methods and the four micro-organism pretreatment methods were investigated to test the effect of lignin and hemicellulose degradation. In chemical pretreatment, sodium hydroxide pretreatment with a supplement of hydrogen peroxide proved to be the most productive way in generating the highest faction of α-cellulose. Sodium hydroxide pretreatment has been shown to be effective on both lignin and hemicellulose degradation. Hydrogen peroxide pretreatment was found to be a less effective for lignin and hemicellulose degradation, compared with the other two methods. Although with the aid of hydrogen peroxide, the delignification of sodium hydroxide is increased largely. In microbial treatment tests, three strains of fungus have a better performance than that of the bacterium strain. Aspergillus flavus is the most effective one in cellulose production. However, bacterium strain, Bacillus licheniformis degrades most hemicellulose among all the strains. For the oil sorption tests, sodium hydroxide (NaOH) / hydrogen (H₂O₂) peroxide pretreatment rice husks and Aspergillus flavus pretreatment rice husks were compared for their oil sorption capacity. With the large amount of cellulose present, the oil uptake capacity of NaOH/ H₂O₂ pretreatment has the largest capacity. Meanwhile, uptake kinetics modeling and retention modeling were also used to find the most suitable model for modified rice husks oil sorption capacity test.

Date of Award	2015
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology