Determination of surface-accessible acidic hydroxyls and surface area of lignin by cationic dye adsorption

Loading...
Thumbnail Image
Journal Title
Journal ISSN
Volume Title
School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2014
Major/Subject
Mcode
Degree programme
Language
en
Pages
80-87
Series
Bioresource Technology, Volume 169
Abstract
A new colorimetric method for determining the surface-accessible acidic lignin hydroxyl groups in lignocellulose solid fractions was developed. The method is based on selective adsorption of Azure B, a basic dye, onto acidic hydroxyl groups of lignin. Selectivity of adsorption of Azure B on lignin was demonstrated using lignin and cellulose materials as adsorbents. Adsorption isotherms of Azure B on wheat straw (WS), sugarcane bagasse (SGB), oat husk, and isolated lignin materials were determined. The maximum adsorption capacities predicted by the Langmuir isotherms were used to calculate the amounts of surface-accessible acidic hydroxyl groups. WS contained 1.7-times more acidic hydroxyls (0.21 mmol/g) and higher surface area of lignin (84 m2/g) than SGB or oat husk materials. Equations for determining the amount of surface-accessible acidic hydroxyls in solid fractions of the three plant materials by a single point measurement were developed. A method for high-throughput characterization of lignocellulosic materials is now available.
Description
Keywords
Adsorption, cationic, dye, lignin, surface-accessible, surface, area
Other note
Citation
Sipponen, Mika Henrikki & Pihlajaniemi, Ville & Littunen, Kuisma & Pastinen, Ossi & Laakso, Simo. 2014. Determination of surface-accessible acidic hydroxyls and surface area of lignin by cationic dye adsorption. Bioresource Technology. Volume 169. P. 80-87. ISSN 0960-8524 (printed). DOI: 10.1016/j.biortech.2014.06.073.