U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Document Type
Article
Date of this Version
2017
Citation
J Chem Technol Biotechnol 2017; 92: pp. 2032–2037, DOI 10.1002/jctb.5197.
Abstract
BACKGROUND: Synthetic organic polymer flocculants can be highly effective at clarifying suspensions, but these substances may also have negative environmental and health effects. Relatively few studies have been done using biobased flocculants, which are more environment friendly. Hemoglobin (Hb) has previously been demonstrated to be a promising flocculant of kaolin and lignin suspensions. This study examines themethylation of Hb side chain carboxyl groups for the purpose of improving its flocculation performance at near-neutral pH.
RESULTS: Potentiometric titration of methylated Hb (MeHb) showed an approximately 28% degree of methylation when the Hb was suspended in methanol with 0.8 mol L−1 HCl for 48 h. Under some conditions, MeHb clarified suspensions of kaolin at one-quarter the dose that was required for Hb. Furthermore,MeHb exhibited flocculant activity over a wide pH range, compared with Hb. The percentage of original turbidity removedwas37% for Hb while 60%of the original turbidity was removed for MeHb at near-neutral pH (pH = 6.8).
CONCLUSIONS: Very small doses of methylated hemoglobin (MeHb) rapidly clarify suspensions of kaolin. The potential of MeHb as a biobased flocculant for the clarification of water for industrial or municipal use was demonstrated.
Comments
U.S. government work.