Search results for "kraft process"
showing 10 items of 44 documents
Characterization of Chlorolignins in Bleached Kraft Pulp Mill Effluents Using Elemental Analysis and Fingerprinting by CuO Oxidation And Hplc
1994
Abstract Elemental analyses and chemical degradation techniques were applied to characterize lignin compounds in different stages of the chlorine bleaching process and in total mill effluent. Ultrafiltration was used for separation of chlorolignins into three nominal molecular weight fractions. Alkaline CuO oxidation products were analyzed by HPLC with diode array detection. Major compounds were identified by reference to authentic compounds. For comparison, native lignins (MWL), kraft lignins, and humic substances were studied as well. The oxygen, carbon and organic chlorine contents were closely similar in the various mill samples and their fractions. In all mill samples, vanillin and 6-c…
ChemInform Abstract: Chemometrics: An Important Tool for the Modern Chemist, an Example from Wood-Processing Chemistry.
2010
This study briefly outlines the idea of principal component analysis and cross-correlation calculations (applied chemometrics) and presents an illustrative example from wood-processing chemistry. The applicability of chemometric data analysis was demonstrated by investigating the various structural changes that take place in dissolved and degraded lignin ("kraft lignin") during laboratory-scale kraft pulping of Scots pine (Pinus sylvestris) and silver birch (Betula pendula). The structural data (31P NMR and size exclusion chromatographic data) on kraft lignin were further processed by chemometric multivariate techniques (PCA and 2DCC), confirming, for example, that the cleavage of beta-aryl…
Chemometrics: An Important Tool for the Modern Chemist, an Example from Wood-Processing Chemistry
2000
This study briefly outlines the idea of principal component analysis and cross-correlation calculations (applied chemometrics) and presents an illustrative example from wood-processing chemistry. The applicability of chemometric data analysis was demonstrated by investigating the various structural changes that take place in dissolved and degraded lignin ("kraft lignin") during laboratory-scale kraft pulping of Scots pine (Pinus sylvestris) and silver birch (Betula pendula). The structural data (31P NMR and size exclusion chromatographic data) on kraft lignin were further processed by chemometric multivariate techniques (PCA and 2DCC), confirming, for example, that the cleavage of beta-aryl…
Chemometric investigation on structural changes in pine kraft lignin during pulping
2000
Abstract Various structural changes which take place in dissolved lignin during the laboratory-scale kraft pulping of Scots pine (Pinus sylvestris) were studied. Lignin samples were subjected to the alkaline cupric oxide oxidation and the analytical data further processed by various multivariate chemometric techniques (principal component analysis, PCA; principal component regression, PCR; and projection to latent structures, PLS). Several models applicable to the indirect measurement of common pine kraft pulp properties (i.e., total cooking yield, kappa number and ISO brightness) were produced.
Mix design and mechanical performance of geopolymeric binders and mortars using biomass fly ash and alkaline effluent from paper-pulp industry
2019
Abstract This work investigates the use of biomass fly ash (BFA) and an alkaline effluent (AEF), both generated from the Kraft pulp industry, in the preparation of geopolymeric binders and mortars for construction applications. BFA replaced the metakaolin (MK) while the AEF substituted the distilled water used to dissolve NaOH pellets. The mix design aims to maximize the amount of both the wastes and to optimize the materials properties, such as workability and mechanical performance. At the same time, also the environmental impact decreases enhancing the materials' sustainability and facilitating the circular economy. For the previously optimized BFA/MK ratio (70/30 wt.%) several NaOH/Na2S…
Scanning probe microscopy of pine and birch kraft pulp fibres
2000
Abstract Fibres of the conventional pine and birch kraft pulps were characterized by scanning probe microscopy (SPM). The surface characteristics of these pulps taken at the early stages of pulping were compared with those from later stages of pulping (with or without subsequent oxygen/alkali delignification). It was observed that during delignification a granular surface structure was replaced by a fibrillar surface containing various disruptions. The granular and fibrillar regions were particularly well resolved by using phase imaging in tapping mode of SPM. It was concluded that the granular structure corresponded to surface lignin since the decrease in the relative amount of the granula…
Carboxymethylation of alkali extracted xylan for preparation of bio-based packaging films
2012
This study describes the synthesis of carboxymethylxylan (CMX) and investigates its suitability as a film for packaging applications. High-purity polymeric xylan was extracted from commercial bleached birch kraft pulp and converted to CMX with three different degrees of substitution (DSs). The water vapor sorption, mechanical, and barrier properties of the films prepared from CMX were tested. Increasing DS of CMX films resulted in an increase in elongation at break and a decrease in tensile strength and Young's modulus. The DS also affected the barrier properties of the films. CMX films with higher DS showed improved (reduced) oxygen permeability (OP), and the water vapor permeability (WVP)…
Chemical characterization and ultrastructure study of pulp fibers
2020
Abstract Understanding the ultrastructure and chemical characterization of pulp fibers is highly important in utilizing wood as a raw material in a wide scope of applications, such as forest biomass-based biorefineries and low-cost renewable materials. The observation of the ultrastructure is not possible without advanced microscopy and spectroscopy techniques. Therefore, this study focuses on exploring the ultrastructure of pulp fibers with helium ion microscopy (HIM) and scanning electron microscopy (SEM). For the analysis of chemical characterization in the pulp fibers, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were pe…
Identification of lipophilic pollutants discharged from a Finnish pulp and paper mill.
1998
Lipophilic organic compounds originating from kraft pulping and papermaking were identified by straight gas chromatography/mass spectrometry (GC/MS) analyses. Samples analyzed included a primary clarifier effluent (PE) and a secondary clarifier effluent (SE) from the activated sludge treatment plant of a Finnish ECF-bleached (Elementally Chlorine Free) kraft pulp and paper mill. Liquid-liquid extraction composition of PE was compared with solid phase extraction (SPE) and dialysis of a semipermeable membrane device (SPMD) exposed to PE. Dichloromethane extracts of particulate material isolated from PE, sludges from both the primary and secondary clarifier, a sediment collected in the vicinit…
Vertical distribution of AhR-activating compounds in sediments contaminated by modernized pulp and paper industry
2013
Increased ethoxyresorufin-O-deethylase (EROD) activity is a sensitive biomarker of exposure to the chemicals which activate the aryl hydrocarbon receptor (AhR) and induce the cytochrome P450 system, such as many polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs). Pulp bleaching was one of the main sources of PCDDs and PCDFs until elemental chlorine free (ECF) and total chlorine free bleaching processes since 1990s have remarkably decreased but not completely eliminate discharges of these chemicals. In addition, historically contaminated sediments may act as a source of these persistent contaminants. In this study, the contam…