Search

Raman spectroscopy and micro-Raman mapping have been used to study the distribution of different chemical components at the surface of coated papers. The paper coatings contain organic nanoparticles with a structure of poly(styrene-co-maleimide) and encapsulated vegetable oils. Raman spectroscopy is able to differentiate between various types of oil, i.e., polyunsaturated, monounsaturated, or saturated, and indicates that the degree of imidization and reactivity of the oil (amount of free oil) complement each other. The surface mapping over large areas (5 × 5 mm2) illustrates good homogeneity of the coating layer and even surface coverage. The imide and oil are homogeneously distributed within the coating itself without a tendency for agglomeration. The covered areas of imide and oil mostly overlap for polyunsaturated oils, while larger amounts of oil occur outside the imide zones for monounsaturated and saturated oils. The latter indicates that the oil is partly "free" within the coating and acts as a continuous binder phase. The surface mapping over smaller areas (1 × 1 mm2) shows the coating and cellulose covered areas are complementary. The surface maps confirm that interaction between the coating and paper substrate happens through hydrogen bonding. Heterogeneities in the coating are due to the presence of remaining ammonolyzed maleic anhydride precursors forming amic acid moieties. The organic phase, oil phase, and cellulose substrate can also be differentiated by principal component analysis of the surface maps. [ABSTRACT FROM AUTHOR]

Pulp and paper mills generate large amounts of waste organic matter that may be converted to renewable energy in form of methane. The anaerobic treatment of mill wastewater is widely accepted however, usually only applied to few selected streams. Chemical oxygen demand (COD) removal rates in full-scale reactors range between 30 and 90%, and methane yields are 0.30–0.40 m 3 kg −1 COD removed. Highest COD removal rates are achieved with condensate streams from chemical pulping (75–90%) and paper mill effluents (60–80%). Numerous laboratory and pilot-scale studies have shown that, contrary to common perception, most other mill effluents are also to some extent anaerobically treatable. Even for difficult-to-digest streams such as bleaching effluents COD removal rates range between 15 and 90%, depending on the extent of dilution prior to anaerobic treatment, and the applied experimental setting. Co-digestion of different streams containing diverse substrate can level out and diminish toxicity, and may lead to a more robust microbial community. Furthermore, the microbial population has the ability to become acclimated and adapted to adverse conditions. Stress situations such as toxic shock loads or temporary organic overloading may be tolerated by an adapted community, whereas they could lead to process disturbance with an un-adapted community. Therefore, anaerobic treatment of wastewater containing elevated levels of inhibitors or toxicants should be initiated by an acclimation/adaptation period that can last between a few weeks and several months. In order to gain more insight into the underlying processes of microbial acclimation/adaptation and co-digestion, future research should focus on the relationship between wastewater composition, reactor operation and microbial community dynamics. The potential for engineering and managing the microbial resource is still largely untapped. Unlike in wastewater treatment, anaerobic digestion of mill biosludge (waste activated sludge) and primary sludge is still in its infancy. Current research is mainly focused on developing efficient pretreatment methods that enable fast hydrolysis of complex organic matter, shorter sludge residence times and as a consequence, smaller sludge digesters. Previous experimental studies indicate that the anaerobic digestibility of non-pretreated biosludge from pulp and paper mills varies widely, with volatile solids (VS) removal rates of 21–55% and specific methane yields ranging between 40 and 200 mL g −1 VS fed. Pretreatment can increase the digestibility to some extent, however in almost all reported cases, the specific methane yield of pretreated biosludge did not exceed 200 mL g −1 VS fed. Increases in specific methane yield mostly range between 0 and 90% compared to non-pretreated biosludge, whereas larger improvements were usually achieved with more difficult-to-digest biosludge. Thermal treatment and microwave treatment are two of the more effective methods. The heat required for the elevated temperatures applied in both methods may be provided from surplus heat that is often available at pulp and paper mills. Given the large variability in specific methane yield of non-pretreated biosludge, future research should focus on the links between anaerobic digestibility and sludge properties. Research should also involve mill-derived primary sludge. Although biosludge has been the main target in previous studies, primary sludge often constitutes the bulk of mill-generated sludge, and co-digestion of a mixture between both types of sludge may become practical. The few laboratory studies that have included mill primary sludge indicate that, similar to biosludge, the digestibility can range widely. Long-term studies should be conducted to explore the potential of microbial adaptation to lignocellulosic material which can constitute more than half of the organic matter in pulp and paper mill sludge. [ABSTRACT FROM AUTHOR]

Abstract: The small rusty stains (foxing) frequently found on historic paper documents, books, and prints have generally been analysed in the past by optical microscope through their morphochromatic appearance under visible light and UV radiation. Despite increased research efforts with more sophisticated techniques (mainly SEM and XRF), the biotic or even chemical origin of these stains remains unclear. The purpose of this paper is to verify to what extent a simple technique such as FTIR-ATR spectroscopy can be utilised for a clearer understanding of the controversial nature of foxing. Since this technique is sensitive to several organic chemical groups that are in common with both fungi and gelatine-sized ancient paper, some modern cardboards stained by biotic foxing have been selected for the analyses. The results clearly show the importance of FTIR and mycological analyses for the identification of residual microfungal agents, together with the by-products of their activity on paper substrates. [Copyright &y& Elsevier]

Abstract: The treatment of additive-free hand sheet paper samples with cold plasma was carried out and showed that cellulose can be chemically linked with reactive natural products, namely myrcene (My) and limonene (LM). Contact-angle measurement and X-ray photoelectron spectroscopy (XPS) were used to ascertain the occurrence of the grafting. Indeed, the contact-angle value of a drop of water deposited at the surface of paper increased from 30° for unmodified substrate to about 105 and 107°, for LM- and My-treated samples, respectively. In fact, LM- and My-treated surfaces were rendered totally apolar. Indeed, the polar contribution to the surface energy decreased from about 23 mJ/m2 for pristine samples to practically zero for treated ones. The treated surfaces displayed water-barrier properties; the penetration of the liquid was reduced significantly after LM and My treatments. The XPS spectra showed that the modification with LM and My gave rise to very significant change in the O/C ratio, as well as in the intensity of the C1 peak assigned to aliphatic carbon sequences. [Copyright &y& Elsevier]

Abstract: Oil palm empty fruit bunches were used as an alternative raw material to obtain cellulosic pulp. Pulping was done by using high-boiling point organic solvents of decreased polluting power relative to classical (Kraft, sulphite) solvents but affording operation at similar pressure levels. The holocellulose, α-cellulose and lignin contents of oil palm empty fruit bunches (viz. 66.97%, 47.91% and 24.45%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using ethyleneglycol, diethyleneglycol, ethanolamine and diethanolamine under two different sets of operating conditions, namely: (a) a 70% solvent concentration, 170°C and 90min; and (b) 80% solvent, 180°C and 150min. The solid/liquid ratio was six in both cases. The amine solvents were found to provide pulp with better properties than did the glycol solvents. Ethanolamine pulp exhibited the best viscosity and drainage index (viz. 636mL/g and 17 °SR, respectively), and paper made from it the best breaking length (1709m), stretch (1.95%), burst index (0.98kN/g) and tear index (0.33mNm2/g). Operating costs can be reduced by using milder conditions, which provide similar results. In any case, the amines are to be preferred to the glycols as solvents for this purpose. [Copyright &y& Elsevier]

This paper deals with the study of the kinetic migration of a series of organic compounds representative of potential contaminants in packaging materials and used as surrogates ( o-xylene, acetophenone, dodecane, naphthalene, 2,3,4-trichloroanisole, benzophenone, isomeric mix of diisopropylnaphthalene, diisobutyl phthalate and methyl stearate). Migration to one side of a solid simulant, Tenax®, also referred to as MPPO (modified polyphenylene oxide), was investigated in this study. One spiked sample of multilayer material was used to optimise the extraction procedures for the multilayer paper-based material and the Tenax as well as to perform kinetic migration studies. Three sequential extractions using ethanol were necessary for the strips of the multilayer material but only one extraction was necessary for the solid simulant to obtain >70% recovery of the surrogates. These results enabled us to specify the extraction requirements of the multilayer sample and the solid simulant and as well as those of the migration tests at high temperature using Tenax as solid simulant. The matrix effect associated with the extraction of the contaminants from the multilayer sample is also discussed. [ABSTRACT FROM AUTHOR]

Capillary zone electrophoresis was used for a comprehensive characterisation of several classes of degradation products from old books. Using different methods with direct and indirect UV detection, three categories of organic compounds were investigated, namely low-molar mass organic acids, aromatic lignin derivatives, and simple carbohydrates. The occurrence of these compounds in paper depended on the state of degradation and on the type of pulp. Formic, acetic, glycolic, succinic, and lactic acids originated from holocellulose degradation. In lignocellulosic papers, acetosyringone, 4-hydroxyacetophenone, 4-hydroxybenzaldehyde, vanillin, vanillic acid, furoic acid, and 4-hydroxybenzoic acid were attributable to the lignin fraction. These two classes of compounds could be analysed directly from the aqueous extracts of papers. Glucose and cellooligomers formed through cleavage of the cellulose chain, while the hydrolysis of hemicelluloses yielded mainly pentoses among which arabinose and xylose were the most abundant. The carbohydrates were derivatised with 4-aminobenzoic acid ethyl ester prior to analysis. All the organic compounds identified were found in a panel of papers from various origin (rag, kraft, and groundwood pulps) and diverse states of deterioration, whether naturally or artificially aged. The production of these compounds was followed during the accelerated ageing of the papers and an attempt to pointing to possible molecular indicators of paper degradation was made. [Copyright &y& Elsevier]

In this study, capillary electrophoresis (CE) was used for separation of inorganic and organic ions from waters of paper and paperboard machines at mills. The instrument was constructed for on-line measurements by building a batch-type sample feeding unit. Chloride, thiosulphate, sulphate, oxalate, sulphite, hydrogen sulphide, formate, carbonate, phosphate and acetate in the process water samples were separated using an ion-specific separation system in CE with dicarboxylic acid buffer (pH 8.2), with pyridinium-2,3-dicarboxylic acid modified with commercial NICE-Pak OFM&z.sbnd;OH solution (pH 12.0) or with a cetyltrimethylammonium bromide solution modified with chromate (pH 10.6). In addition, Analis CEofix Anions 8 electrolyte solution was tested in on-line studies at mills. It allowed 5 min separation time for the anions. Aluminium was determined at pH 3.6 in 10 min by using a laboratory-made imidazole buffer modified with 18-crown 6-ether. The developed CE systems were used to monitor the concentrations of sulphur species in dithionite degradation, to estimate corrosion degree in the water tanks, to monitor formaldehyde as the biocide chemical in wire washing and, in general, to observe process disturbances resulting from chemical feedings and their sites. The CE combination was on-line coupled to eight different process machines for continuous monitoring of concentrations for periods between two weeks and one month at paper and pulp mills in Finland. [Copyright &y& Elsevier]

Solid-phase microextraction (SPME) coupled to gas chromatography/mass spectrometry (GC/MS) has been applied to the analysis of volatile organic compounds emitted from a naturally aged groundwood pulp paper originating from an old book in order to access the products produced through the decomposition reactions occurring in paper upon ageing. Two different extraction methods were developed and compared: headspace SPME and contact SPME. The influence of few extraction parameters were tested in order to define the best extraction conditions. An optimised non-destructive contact SPME method was elaborated and allowed the characterisation of more than 50 individual constituents. [Copyright &y& Elsevier]