Optimization of Dissolution Conditions During Fractionation of Corn-cob in ZnCl2.4H2O/Urea Solvent System: A Statistical Approach



Olayile Ejekwu1, Augustine Omoniyi Ayeni2, Michael Olawale Daramola1, *
1 School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, South Africa
2 Department of Chemical Engineering, Covenant University, Lagos, Nigeria

Abstract

Background:

The choice of a suitable pretreatment method and the adjustment of the pretreatment parameters for efficient conversion of biomass to value-added products is crucial to a successful biorefinery concept.

Objectives:

Pretreatment of corn cob using ZnCl2.4H2O/ Urea was carried out and optimized in this study. Effect of the pretreatment conditions on cellulose recovery, hemicellulose recovery in the liquid fraction and lignin recovery was investigated via response surface methodology approach.

Results:

For cellulose recovery, time and temperature, and solvent concentration were significant factors. Hemicellulose recovery in the liquid fraction is impacted by time and solvent concentration, while lignin recovery is affected by time and temperature. Using numerical optimization by desirability function, optimum pretreatment conditions obtained were: 90 min, 120°C and concentration of 71.32%/28.68 (w/w) ZnCl2.4H2O/ Urea. At these conditions, the predicted recovery for cellulose, hemicellulose and lignin were 99.03%, 27.18% and 72.43%, respectively, with a desirability of 0.902. The actual recovery was 91%, 29% and 68% for cellulose, hemicellulose and lignin, respectively, at the same conditions.

Conclusion:

These results indicate that the investigated variables have pronounced effect on the pretreatment of corn cob. Therefore, optimum conditions are required for recovery of desired composition before conversion to value-added products.

Keyword: Pretreatment, Lignocellulosic biomass, Molten hydrate salts, Response surface methodology, Solvent, Central Composite Design.


Abstract Information


Identifiers and Pagination:

Year: 2019
Volume: 13
Publisher Item Identifier: EA-TOCENGJ-2019-2

Article History:

Received Date: 28/01/2019
Revision Received Date: 19/03/2019
Acceptance Date: 21/03/2019
Electronic publication date: 10/04/2019
Collection year: 2019

© 2019 Ejekwu et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Correspondence: Address correspondence to this author at the School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, South Africa; Tel: +27117177536; E-mail: Michael.daramola@wits.ac.za