title: PDADMAC as a flocculant for lignosulfonate of NSSC pulping process.
abstract: The spent liquor (SL) of neutral sulfite semi-chemical (NSSC) pulping process contains about 8 wt% lignocelluloses that can be extracted and used in the production of value-added materials. In this work, a flocculation process followed by centrifugation was considered for isolating lignosulfonate and hemicelluloses from SL. It was observed that, by adding 20 mg/g of polydiallyldimethylammuniom chloride (PDADMAC) with 100,000-200,000 g/mol molecular weight to SL, 45% of lignosulfonate and 39% of hemicelluloses were removed at 30°C. The lignocellulose removal was more efficient for the dual flocculation system of low and high molecular weights PDADMAC than for individual PDADMAC systems. Overall, 49% of lignosulfonate, 47% of hemicelluloses and 97% of turbidity were removed from SL from the dual system when 10 mg/g low molecular weight PDADMAC and 10 mg/g high molecular weight PDADMAC were added to the SL at 30°C, subsequently. The thermogravimetric analysis (TGA) of generated flocs showed that all samples had similar thermal behaviour and 13-16 wt% of flocs remained as ash after burning at 700°C in nitrogen. As the flocs are made of lignocellulosic materials and they are thermally stable, they could be used as fillers in paper board production. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:686-691, 2016.
authors.affiliation: Chemical Engineering Dept., Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Farshad
authors.initials: F
authors.lastname: Oveissi
authors.affiliation: Chemical Engineering Dept., Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Sitter
authors.affiliation: Chemical Engineering Dept., Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Pedram
authors.initials: P
authors.lastname: Fatehi
mesh_terms: D002498:Centrifugation; D005427:Flocculation; D008031:Lignin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D011095:Polyethylenes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013447:Sulfites / Q000737:chemistry*
chemical_list: D011095:Polyethylenes; D000644:Quaternary Ammonium Compounds; D013447:Sulfites; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; C001545:lignosulfuric acid; D008031:Lignin
keywords: NSSC process; PDADMAC; biorefinery; flocculation; spent liquor