Ultrafiltration of Kraft Black Liquor from Two Swedish Pulp Mills

Holmqvist, Anders; Wallberg, Ola; Jönsson, Ann‐Sofi

doi:10.1205/cherd.04204

Cited by 44 publications

(32 citation statements)

References 12 publications

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“…Such a lignin has a low ash and high dry content. As an alternative option, lignin in BL can be fractionated by membrane filtration prior to precipitation (Wallberg et al 2003;Holmqvist et al 2005;Brodin et al 2009). In this case, the lignin has a more narrow molecular weight (MWt) distribution (MWtD).…”

Section: Introductionmentioning

confidence: 99%

The molecular properties and carbohydrate content of lignins precipitated from black liquor

Zhu

Westman²,

Theliander³

2014

Holzforschung

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Precipitation and utilization of lignin from black liquor (BL) offers many promising advantages to modern kraft pulp mills. A novel process, known as "LignoBoost", has recently been introduced as a process for separating lignin from BL; it results in lignins with a low ash and high dry solid content. There is a lack of knowledge regarding the influences of process parameters on the behavior of lignin in the precipitation step. In this study, the yield of precipitated lignin and its average molecular weight (MWt) and carbohydrate content were the focus. Nuclear magnetic resonance (NMR) analysis showed that the lignin yield increased at lower pH and temperatures or when the ion strength of BL was elevated. High yield lignins contained more low MWt components and such lignins have more phenolic OH and methoxy groups. Xylan content of the lignins decreased with decreasing pH and increasing temperature, but glucomannan content was virtually unaffected by the conditions of precipitation.

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Section: Introductionmentioning

confidence: 99%

The molecular properties and carbohydrate content of lignins precipitated from black liquor

Zhu

Westman²,

Theliander³

2014

Holzforschung

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“…Ultra-filtration of black liquor for the extraction of lignin has been studied in several previous investigations Holmqvist et al 2005;Wallberg et al 2006). The lignin was extracted with a polymeric membrane, i.e., polyethersulfones (18 %) containing polyvinyl pyrrolidone(1 %) in a laboratory unit equipped with dead-end cell.…”

Section: Extraction and Chemical Modification Of Ligninmentioning

confidence: 99%

Utilization of waste lignin to prepare controlled-slow release urea

Behin

Sadeghi

2016

Int J Recycl Org Waste Agricult

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Purpose The present work reports an economically attractive improvement in the area of producing particulate slow release nitrogen fertilizer using lignin as a waste effluent of pulp and paper manufacturing process. Methods An improved coating of modified lignin was applied on the surfaces of the individual urea particles. The Kraft and Sulfite black liquors obtained from two different paper pulping units and were used as sources of sulfate and sulfite lignin, respectively. Chemical modification of extracted lignin was performed through acetylation reaction by acetic acid/sodium metabisulfite to increase its hydrophobicity character. In a separate experiment, a thin layer of synthesized acetylated lignin was coated on granular urea by fluidized-bed technique. The nitrogen release of synthesized fertilizer in the water and soil was examined by the Kjeldahl method. Results The analysis of FTIR spectra indicated the changes in the functional groups of acetylated lignin. Petrographic photography and scanning electron microscopy (SEM) analyses demonstrated a uniform and homogeneous covering of the urea surface. The 7 day nitrogen release rate of urea coated by acetylated lignin in soil was obtained 36.3 and 45.3 % for Kraft and Sulfite lignin, respectively, whereas this value was 59 % for sulfur coated urea. Conclusions Using industrial wastewater as source of lignin gives satisfactory results for industrial applications and yields a quality green fertilizer product with reduced operation difficulties while considerably preserving the environment.Keywords Controlled release fertilizer Á Fluidized-bed coating Á Kraft and sulfite liquor Á Modified lignin coated urea Abbreviations CRF Controlled-release fertilizers FTIR Fourier transform infrared SCU Sulfur coated urea SEM Scanning electron microscopy

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“…A considerable research effort has taken place in the following fields (1) improvement of lignin isolation processes from black liquor, specially using precipitation (Norgren, 2001;Norgren and Edlund, 2003;Öhman et al, 2007a,b;Sun et al, 1999) and ultrafiltration methods (Bhattacharjee et al, 2006;Holmqvist et al, 2005;Liu et al, 2004a,b;Wallberg et al, 2006); and, (2) as focused earlier, development of new lignin applications. In Fig.…”

Section: Feedstock: Lignin General Aspectsmentioning

confidence: 99%