Sorption of copper by chemically modified aspen wood fibers
Date of Original Version
Sorption of copper (Cu2+) by untreated and treated (bleaching and hydrolysis) aspen wood fibers, cellulose and lignin was examined to understand the Cu2+ sorption behavior by these natural sorbents. All sorbents were characterized by solid-state 13C NMR and FTIR. Bleaching broke up aromatic structures and increased hydrophilicity of the fibers, whereas hydrolysis decreased carbohydrate content, producing a more hydrophobic structure. Copper sorption was a function of pH; the percentage of Cu2+ sorption steadily increased from pH 1.5 to 4.5 with a maximum sorption amount at around pH 5.5 for all the materials. All isotherms fitted well to the Langmuir equation. Bleached sample (BL) had a highest sorption capacity, followed by untreated (UTR), cellulose (CEL), and hydrolyzed (HHY), while lignin (LIG) had little Cu2+ sorption under the studied conditions. The results suggested that carboxyl (-COOH) and hydroxyl (-CHOH) in carbohydrates are mainly responsible for Cu2+ sorption, and that ion exchange may be a main sorption mechanism for the studied sorbents. Additionally, the sorption capacity for Cu2+ on all sorbents decreased with the increase of the initial concentrations of Ca2+, Na+ or Al3+. Copper sorption decreased rapidly at low initial concentrations of Ca2+, Na+ or Al3+. However, the decline of Cu2+ sorption slowed down when initial Na+ and Ca2+ concentration was higher than 0.05 M or initial Al3+ concentration was greater than 0.005 M, indicating that specific adsorption may be taking place. Therefore, the majority of sorbed Cu2+ to aspen wood fibers could be through ion exchange (especially, for UTR, BL and CEL), while a faction of sorbed Cu2+ via inner-sphere complex (or specific adsorption). © 2009 Elsevier Ltd. All rights reserved.
Publication Title, e.g., Journal
Huang, Liyuan, Zhaoyang Ou, Thomas B. Boving, Julian Tyson, and Baoshan Xing. "Sorption of copper by chemically modified aspen wood fibers." Chemosphere 76, 8 (2009): 1056-1061. doi: 10.1016/j.chemosphere.2009.04.030.