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Petroleum-based materials are often used in the packaging industry. However, the single use value of such products can be problematic with regard to proper waste disposal. As such, molded pulp packaging can be used as an alternative, given its ease of recycling, composting, and eventual biodegradation. In this work, we aims to study the pulp properties of sunn hemp and its usage as molded pulp products. For this purpose, unbleached beaten and unbeaten soda pulps derived from the whole stem of sunn hemp were examined for their fiber morphology, fibrillation, fiber classification, and physical properties. The sunn hemp pulp was subsequently molded using a batch molding machine. To determine the hydrophobicity of the molded pulp products, the molded samples were manufactured with and without additives. Finally, some properties of the molded pulp products were examined and compared with the commercially available bleached bagasse molded pulp products. It was observed that the molded products made from sunn hemp pulp with additives had a higher water contact angle than that of the commercial products. In terms of general usage, the molded products from sunn hemp pulp with additives were found to be capable of storing hot water, hot cooking oil, as well as microwaving water. We concluded that the sunn hemp pulp could be used as an alternative fibrous raw material in the production of molded pulp packaging. [ABSTRACT FROM AUTHOR]

Abstract Industrialization and urbanization are the key drivers to threaten the environmental quality and natural resources. Traditionally, pulp and paper industry has been highly reliant on forest based resources for its escalation. Shortage of forest based raw materials, strict environmental regulations and policies have compelled the industry to seek for alternate raw materials for its production. Mills are now focusing on exploring the potential of different agro wastes such as cereal straws and bagasse etc. In present research, sugarcane trash, one of the most abundant agro residues in India, was investigated for its capability in pulping and bleaching. Chemical characterization of sugarcane trash showed that it contains 40.4% cellulose, 33.2% hemicelluloses, 17.4% lignin and 6.45% ash content with 2.76% silica. To cook sugarcane trash with soda pulping method, 14% alkali charge, 15 min time and 162 °C temperature was found to be optimum and pulp of kappa no. 19.8 was prepared that exhibited good strength properties. Bleaching of pulp was carried out using elemental chlorine (Cl 2), hypochlorite and chlorine dioxide (ClO 2) based sequences. Replacement of Cl 2 with ClO 2 has significant impact on strength properties and effluent characteristics. Oxygen delignification stage was incorporated prior to ClO 2 that resulted in improved optical properties of pulp with noticeable reduction in wastewater load. This paper elaborates the need of using sugarcane trash in paper mills with environment friendly pulping and bleaching processes to combat with the problem of waste management, wastewater load reduction during bleaching and substitute for wood based raw materials in papermaking. Highlights • Use of sugarcane trash for papermaking, an approach for waste management. • Soda pulping is an effective approach for converting waste to fibrous material. • Conventional bleaching leading to high effluent load and low strength properties. • Improvement in effluent quality and paper properties by chlorine dioxide bleaching. • Oxygen stage prior to dioxide bleaching further lowers effluent load. [ABSTRACT FROM AUTHOR]

Abstract: The weight share of the pith, nodes and internodes in the stalks of Miscanthus, as well as the types of cells in these anatomical parts, were examined. Studies have shown that the pith contains mainly parenchyma cells, nodes—short fibres and palisade parenchyma cells, while internodes contains mainly fibres, which are accompanied by a certain amount of vessels and parenchyma cells. Then the whole stalks of Miscanthus were subjected to pulping using the kraft and soda pulping methods. These studies have shown that hard, regular, soft and very soft kraft pulps can be obtained using a lower amount of active alkali, with comparable or higher screened yield of pulp than is the case of pulping of birch. Furthermore, it was found that the content of knots and shives was lower in the digester hard and regular kraft pulps from Miscanthus compared to birch kraft pulp. Of the two pulping methods studied, kraft pulping gives better results than soda pulping concerning the considerably higher yield of pulp.Graphical abstract: [ABSTRACT FROM AUTHOR]

In this research, soda lignin was extracted from Bambusa bambos using a soda pulping process, and interaction effects of pulping variables were statistically analyzed by the central composite design methodology. A statistical model predicted that the maximum recovery of soda lignin would be 104.6 mg/g of biomass in the following optimized process conditions: sodium hydroxide concentration (1.3% w/v), biomass concentration (10% w/v) and 150 min of pulping. The precipitated soda lignin was sequentially fractionated with organic solvents (chloroform, dichloromethane and n-butanol). The extracted soda lignin fractions, chloroform fraction (F1), dichloromethane (F2) and n-butanol (F3) were subsequently characterized by UV, FTIR, thermogravimetric analysis and 1H NMR spectral analysis. According to analytical characterization of lignin fractions, the molecular weight of lignin fractions increased gradually from fraction 1 to 3 and their polydispersity decreased dramatically compared with the unfractionated lignin. TG/DTG showed that the low molecular weight fractions generally have lower thermal stability. Functional group analysis results indicated that the guaiacyl unit content, molecular weight and thermal stability increased from F1 to F3, whereas the phenolic acid content significantly decreased. Solvent fractionation method to separate well defined structure of lignin molecules, which are likely having the extreme potential applications. [ABSTRACT FROM AUTHOR]

Laboratory-scale studies were carried out on ozone bleaching of wheat straw soda pulp. Effects of five variables--pH, consistency, time, temperature, and ozone dose--on three pulp parameters-- kappa number, brightness, and viscosity-were determined using Plackett-Burman experimental design. Results showed that for the parameter kappa number of pulp, ozone dose is the most important factor followed by pH and consistency. Pulp parameter viscosity is affected by factor pH, followed by consistency and ozone dose. Brightness of the wheat straw pulp mostly depends on factor ozone dose, followed by pH. [ABSTRACT FROM AUTHOR]

MnX/SiC/S-carbon nanosheets (MnX/SiC/S-CN) were synthesized by using soda pulping black liquor (SPBL) as raw material and template. The phase components of MnX/SiC/S-CN were controlled and designed by changing doping amount of MnSO 4 . Herein, the hollow mesoporous MnO/MnS/SiC/S-carbon nanosheet (MnO/MnS/SiC/S-CN) composites were prepared and exhibited excellent electrochemical performances. As anode, the MnO/MnS/SiC/S-CN electrode delivered good cycle performance (756 mAh g −1 after 50 cycles at a current density of 1000 mA g −1 ) and remarkable rate capability (685 mAh g −1 when the current density backed to the initial current of 1 A g −1 after a high current density ranging from 1 A g −1 to 20 A g −1 for 70 cycles). The presence of flexile SiC/S-graphitized carbon nanosheets (SiC/S-GCN) is able to buffer the large volume expansion and contraction of MnO/MnS nanoparticles during the cycling process. Otherwise, the hollow porous is another key factor that not only decreases the transmission distance of Li + and electron, but also provides internal and external surface for the attachment of Li + . Recycled resources of SPBL help protect our environment, keep our planet healthy and provide highly economic values. [ABSTRACT FROM AUTHOR]

Cellulose nanofibrils and lignin were simultaneously isolated from waste jute bags using soda cooking pretreatment method. Soda cooking resulted in reduction of recalcitrance of lignocellulose biomass leading to hydrolysis of hemicellulose into sugars, which was subsequently washed, leaving a residue of cellulose and lignin.The chemical composition, yield of lignin and cellulose were assessed using TAPPI method and ASTM standards, respectively. Yields of lignin and cellulose were 58 and 45%, respectively, calculated separately on the basis of their content in the jute bags. FTIR results confirmed the removal of lignin and hemicellulose from raw jute fibers during soda cooking process. H NMR results depicted the aromatic structure of lignin which was further confirmed by UV results which clearly indicated the presence of phenolic compounds. The thermal stability of cellulose nanofibrils and lignin was higher than raw jute fibers. SEM showed cylindrical cellulose nanofibrils and agglomerates of amorphous and crystalline region of lignin. Size of jute fibers decreased to 12–18 nm whereas the crystallinity increased after chemical and mechanical treatments studied using TEM and XRD, respectively. The study confirmed the isolation of cellulose nanofibrils and lignin extraction discarding the hemicellulose using single pot treatment. [ABSTRACT FROM AUTHOR]

World is facing challenges to reduce global environmental issues including waste management, green house gas emissions, pollution, deforestation and depletion of non renewable resources originated due to speedy industrial and urban development. To protect environmental resources, strict legislations are being made by the governments of developing and developed world. Due to such issues, pulp and paper industry is sarcastically facing shortage of forest based raw materials for paper production. Most of the mills have either start up with non wood based raw materials or recycled papers in place of conventional forest based resources. Rice straw, a lignocellulosic residue is abundantly available in wood short countries like India and China and can be utilized in pulp and paper industry. In present study it was found that rice straw consisted of cellulose (33.3 ± 0.47%), pentosan (27.3 ± 0.36%), lignin (13.0 ± 0.07%), ash (12.6 ± 0.11%) and silica (11.7%). The higher amount of carbohydrates and less lignin content in rice straw in comparison to hardwoods and softwoods can be made as a alternate raw material for pulp and paper mills. Out of soda and soda anthraquinone - methods for converting rice straw to pulp, -Later was found to be a better option as it gives high pulp yield (62.4%) and better strength properties of the pulp. The bleaching of soda--anthraquinone rice straw pulp with chlorine dioxide based bleaching sequence was found better over elemental chlorine based sequence as it improved the pulp strength properties and reduced the bleaching effluent load. The adsorbable organic halides - indicative of biorefractory, accumulative and toxic compounds were reduced by 66% when chlorine dioxide bleaching was used. Such approach of using agricultural waste as a raw material for making paper can prove to be valuable towards waste utilization, pollution control and for sustainable growth of industry. [ABSTRACT FROM AUTHOR]

In this work we have characterized a mild soda pulped birch ( betula pendula ) lignin after a novel pressurized hot water extraction pilot process. In the process hemicelluloses are first isolated from woods chips with hot water at oxygen-starved conditions, followed by mild alkali pulping at oxygen-starved conditions to remove lignin from the cellulose. Lignin was precipitated, washed and fractionated from the black liquor and characterized by quantitative 13 C NMR, 13 C DEPT experiments, 31 P NMR, 2D HSQC, FTIR, size exclusion chromatography (SEC), elemental analysis, pyrolysis-gas chromatography-mass spectrometry ( py -GC–MS), methoxyl group quantification and residual carbohydrate analysis after methanolysis. The structure was compared to a MWL of birch obtained from the same wood chips and the differences were an increase in phenolic hydroxyl groups, carboxylic groups, polydispersity index, and reduction of aliphatic hydroxyl groups. The process resulted in β-O-4 cleavage and condensation of the structure. This lignin is therefore suitable to be used in its polymeric form, rather than for degradation of the structure to small building blocks. [ABSTRACT FROM AUTHOR]

Bagasse was pretreated by pectinase, and both the control and pretreated bagasse were subjected to soda-anthraquinone (AQ) pulping. There were significant improvements in pulp properties after pectinase treatment, such as relative increases of brightness (5.5%), breaking length (17.1%), burst factor (16.5%), and tear factor (7.0%). The samples were analyzed by a fiber analyzer, scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The pectinase treatment changed the material properties, which would improve the efficiency of subsequent pulping, such as increasing the fiber length (20.0%), lowering the fines length (10.6%), and increasing the percentage of flexible fiber. Pectinase treatment removed some non-cellulose components; in particular, the pectin and alcohol-benzene extractives were decreased by 19.4% and 37.3% after enzymatic treatment. The hemicellulose and lignin were decreased by 5.5% and 1.9%, respectively. A bulkier and more collapsed fiber surface was observed in the treated fibers, which suggested greater pore volume and more accessible surface area. Treatment caused a slight incline by 4.8% in the crystallinity index. Some chemical structures in pectin, hemicellulose, and lignin were partly broken, showing the effect of pectinase treatment on the degradation of non-cellulose components. Pectinase treatment prior to pulping is therefore recommended, given its efficiency and eco-friendly nature. [ABSTRACT FROM AUTHOR]

The potential usefulness of an invasive common reed as biomass feed to a biorefinery was investigated. This investigation focused on the cellulosic fiber and a comparison of with and without a hot-water extraction (HWE) pretreatment process step. Handsheets were made before and after bleaching and compared to handsheets made from other pulped grass family (Poaceae) fibers. Machine-made simulated copy-grade paper was compared with and without HWE at varied percentages of reed replacement for hardwood fiber in the furnish. The HWE appeared to cause a dramatic increase in the tensile and burst strength while the tear strength reduced slightly. The effects of HWE on woody biomass strength properties were compared. [ABSTRACT FROM AUTHOR]

Amphipathic lignin derivatives (A-LDs) prepared from the black liquor of soda pulping of Japanese cedar are strong accelerators for bioethanol production under a fed-batch simultaneous enzymatic saccharification and fermentation (SSF) process. To improve the bioethanol production concentration, conditions such as reaction temperature, stirring program, and A-LDs loadings were optimized in both small scale and large scale fed-batch SSF. The fed-batch SSF in the presence of 3.0 g/L A-LDs at 38 °C gave the maximum ethanol production and a high enzyme recovery rate. Furthermore, a jar-fermenter equipped with a powerful mechanical stirrer was designed for 1.5 L-scale fed-batch SSF to achieve rigorous mixing during high substrate loading. Finally, the 1.5 L fed-batch SSF with a substrate loading of 30% (w/v) produced a high ethanol concentration of 87.9 g/L in the presence of A-LDs under optimized conditions. [ABSTRACT FROM AUTHOR]

The effect of fiber characteristics from old corrugated container (OCC) paper on the strength properties of OCC/polypropylene composites was evaluated. Fibers with different contents of lignin (2.8%, 3.8%, 5.3%, and 7%) were produced using soda pulping. Wettability, tear, and tensile strength of the fibers were measured as the indication factors to assess the strength of reinforcing component in the composites. The weight portions of the OCC fibers, polypropylene, and maleic anhydride-grafted polypropylene (MAPP) were selected at 20%, 77%, and 3% of the total weight of the composite, respectively. The composite compounds were formed using a counter-rotating twin screw extruder, and the specimens were made in an injection molding machine. The interaction of fiber characteristics and fiber lignin content on the mechanical properties of composite was investigated. The results revealed that with lower fiber lignin content, both flexural and tensile properties were increased. Consequently, by forming better fiber dispersion and by reducing stress regions in the composite, impact strength was also improved. Lower lignin content resulted in better mechanical properties than fiber characteristics. [ABSTRACT FROM AUTHOR]

Wheat straw was cooked under different pulping processes: Soda (100 °C, 7% NaOH, 150 min), Kraft (170 °C, 16% alkalinity, 25% sulfidity, 40 min) and Organosolv (210 °C, 60% ethanol, 60 min). Once the pulps were obtained, lignocellulose nanofibers (LCNF) were isolated by mechanical process and TEMPO-mediated oxidation followed by a high pressure homogenization. After pulping process, the different pulps were characterized and its chemical composition was determined. The pulps characterization indicates that the Soda process is the process that, despite producing less delignification, retains much of the hemicelluloses in the pulp, being this content a key factor in the nanofibrillation process. Regarding the LCNF obtained by mechanical process, those nanofibers isolated from Organosolv wheat pulp (OWP) and Kraft wheat pulp (KWP) show low values for nanofibrillation yield, specific surface area and greater diameter. However, those nanofibers isolated from Soda wheat pulp (SWP) reach much higher values for these parameters and presents a diameter of 14 nm, smaller than those obtained by TEMPO-mediated oxidation from OWP. Smaller diameters are generally obtained in TEMPO-oxidized LCNF. This work concludes that the lignin content does not affect greatly to obtain LCNF as does the hemicellulose content, so it is accurate to use a soft pulping process. [ABSTRACT FROM AUTHOR]

Face-centered composite design (FCC) was used to study the effect of pulping variables: soda concentration (4-5 wt%), temperature (90–130°C), and pulping time (20–60 min) on the properties of pineapple leaf pulp and paper employing soda pulping. Studied pulp responses were screened yield and lignin content (kappa number). Paper properties, which include tensile index, burst index, and tear index, were also investigated. Effects of the pulping variables on the properties were statistically analyzed using Minitab 16. The optimum conditions to obtain the maximum tensile index were soda concentration of 4 wt%, pulping temperature of 105°C, and pulping time of 20 min. The predicted optimum conditions provided tensile index, burst index, tear index, screened yield, and kappa number of 44.13 kN·m/kg, 1.76 kPa·m2, 1.68 N·m2/kg, 21.29 wt%, and 28.12, respectively, and were experimentally confirmed. [ABSTRACT FROM AUTHOR]

Alkali lignin, an aromatic polymer extracted from soda pulping black liquor, is considered to be a potential source of phenolic-rich bio-oil using pyrolysis technology. This paper investigated the pyrolysis behaviors and kinetics of alkali lignin using thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TGA–FTIR) and pyrolyzer coupled with gas chromatography/mass spectrometer (Py–GC/MS). Results showed that the pyrolysis process of alkali lignin consisted of the three stages: drying stage, fast degradation stage and slow degradation stage. The weight loss rate reached its maximum value of 0.2448 mass%/°C at the temperature of 327 °C. The aromatics (at 1512 cm −1 ) and phenols (at 1261 cm −1 ) were the dominant volatile components according the FTIR spectrum. As the conversion rate increased from 0.05 to 0.9, the activation energy estimated from Flynn-Wall-Ozawa (FWO) method, was raised from 124 to 721 kJ mol −1 . The phenolic compounds, namely guaiacol type (G-), the phenol type (P-), the syringol type (S-), and the catechol type (C-) were the main products from Py–GC/MS experiment. The total phenols and the G-type phenols reached their maximum contents of 78% and 63.43% at 500 °C, respectively. The content of S-type phenols decreased from 17.63% to 10.2% as the temperature increasing from 400 °C to 700 °C, while the contents of P-type and C-type phenols increased from 0.81% to 8.16% and 0.12% to 3.11%, respectively. [ABSTRACT FROM AUTHOR]

The rheograms of wheat straw soda black liquor in a shear rate range of 10–103s−1were investigated by a Physica MCR 100 rheometer. The rheological properties of wheat straw soda black liquor with different solids content were deliberated in 60–100°C temperature range. All samples exhibit shear-thinning properties with the flow behavior index (n) between 0.715 and 0.865. The Arrhenius model was used to explain the influence of temperature on apparent viscosity of soda black liquor. The Arrhenius parameters,ηoandEaare functions of solids content and expressed by the Ostwald-de-Waele model. The empirical model obtained from the study could well depict the combined effect of solid content and temperature within the range of study. It was concluded from the results that temperature along with the solids content had significant effect on the rheological properties of soda black liquor. [ABSTRACT FROM AUTHOR]

Depending on the production method, traditional paper mills often utilize the black liquor by burning it for energy. Hemicelluloses extracted from the raw material prior to pulping could be utilized to produce biochemical fuels. The aim of this study was to pre-extract hemicelluloses from wheat straw by treating the biomass with hot water and alkali (NaOH or the combination NaOH+NaBH4) at varying temperatures and chemical concentrations, and also to integrate resulting solid material to produce pulp and to produce bioethanol and biodegradable films from extracted liquor consisting mostly of xylan. Optimum hot water (135 °C) and alkali pre-extractions (16.7% NaOH at 50 ?C) removed 16.5% and 33.6% of the xylan from the straw structure, respectively. The liquid portion of the hot water (135 ?C) and alkali (16.7% NaOH at 50 ?C) pre-extracted oven-dry (OD) straw yielded up to 7.79% and 6.81% (g/100 g soluble material) ethanol. Good-quality biodegradable films were produced when some gluten and nanocellulose was added to the extracted xylan. Although the hot water pre-extracted pulp yield was slightly lower, its physical and mechanical pulp properties were comparable to those of the corresponding conventional soda pulp. [ABSTRACT FROM AUTHOR]

The performance of coir fiber in the production of linerboard made from soda-anthraquinone (soda-AQ) pulp was evaluated. Based on chemical analysis, the composition of coir fiber is suitable for the pulping process. Out of nine pulping conditions characterized, a pulping condition of 18% active alkali for 90 min cooking time was chosen. These conditions provided the highest screened yield (48.99%), a low rejection yield (0.27%), high viscosity (11.73 cP), and a kappa number (41) that is acceptable for unbleached linerboard production. Beating strengthened the coir pulp. Analyzing the beating revealed that coir pulp was optimized at 1000 to 2000 revolutions, based on a graph of freeness vs. burst index. For all beating conditions (1000 to 8000 revolutions), FESEM micrographs showed the presence of internal and external fibrillation of the fiber, which gradually increased fiber conformability and improved the inter-fiber bonding within the paper formation. Based on its burst strength of 4.57 kPa.m²/g and ring crush test of 1.76 Nm²/g, which complies with the minimum requirement of the industry standard, coir fiber can be considered an alternative fiber source for linerboard production. [ABSTRACT FROM AUTHOR]

Soda-anthraquinone (soda-AQ) pulping of barley straw was used to obtain cellulosic pulps for papermaking purposes. The identified parameters, or variables to be optimized, were operating time, anthraquinone concentration, and PFI refiner revolutions, and the influence of these operating variables on pulp properties was studied. A polynomial model that reproduced the experimental results with errors less than 6% was developed. Operating variables were found (46 min of processing time, 0.4 wt.% of anthraquinone concentration, and 3000 rpm of PFI revolution) that yielded competitive pulp properties (82 °SR beating grade number, 870 mL/g of viscosity, Kappa number of 13, 77 Nm/g of tensile index, and 30% ISO brightness) at reasonable chemical and energy costs. On the other hand, this study highlights the usefulness of this polynomial model as a method to minimize the use of anthraquinone in these pulping processes and to be able to predict what the pulp properties will be. For comparison purposes, new operating conditions were found, and the pulp properties still remain at a very good level for this cereal straw. [ABSTRACT FROM AUTHOR]

This paper reports on the formation of methanol (MeOH) during conventional oxygen delignification (OD) of four typical alkaline pulps, namely, southern pine kraft pulp (SP-KP), wheat straw soda pulp (WS-SP), and eucalyptus kraft pulp (E-KP) with κ numbers (KN) of 32.8 and 16.9 (E-KP32.8 and E-KP16.9). Based on the mass transfer effect of MeOH and a proposed demethoxylation reaction pathway of lignin, two kinds of kinetic models were proposed to predict MeOH formation. The results show that the two-stage pseudo kinetic model with a first-order rate equation is adequate, which was further modified to a first-order kinetic model by means of which MeOH formation during OD of the pulps can be effectively predicted. Finally, the single set of kinetic parameters for the WS-SP, E-KP32.8, and E-KP16.9 pulps was calculated. The proposed kinetic model is considered as a valuable tool for the prediction and control of MeOH formation during OD of various alkaline pulps. [ABSTRACT FROM AUTHOR]

A lignin-rich feedstock, soda-anthraquinone spent pulping liquor, was pyrolyzed in a kiln reactor. The liquor was prepared from mixed northern hardwood chips at a liquor-to-wood ratio of 3.5 L/kg, 16% effective alkali, and an H-factor of 1000 h. The spent liquor was pyrolyzed at 500°C as is, after oxygen oxidation, and with addition of sodium formate to determine the effect on bio-oil yield and product distribution. Contrary to bio-oil from sawdust, a clear phase separation of the liquid product into an aqueous layer and a denser organic layer is obtained. The predominant products found in the organic layer collected after pyrolysis are phenols with varying degrees of methylation and ethylation. The organic yield appears to go through a maximum (32 wt% on spent liquor organics) at around 25 wt% formate added on spent liquor dry solids and subsequently decreases at greater charges. Oxidation of the spent liquor prior to pyrolysis appears to have a detrimental effect on the organic yield. [ABSTRACT FROM AUTHOR]

Organic xerogels were functionalized by incorporating sugarcane bagasse lignin from soda pulping black liquor, not used so far in this materials, with the aim of introducing new functional groups on traditional gels that could improve its adsorptive capacity. Two mixing designs were applied to identify the reactive combinations that allow a well gel formation and to adjust models that predict physical properties. The designs study five components: resorcinol (R, 0.04–0.3), lignin (L, 0.004–0.14), formaldehyde (F, 0.08–0.17), water (W, 0.45–0.8), and NaOH (C, 0.0003–0.0035). The first experimental design was an extreme vertices design and its results showed shrinkage between 4.3 and 59.7 and a bulk density from 0.54 to 1.3; a mass ratio LR/F near 1.5 was required for gel formation. In the second design a D-Optimal was used to achieve better adjusted coefficients and incorporate the largest possible amount of lignin in the gels. Bulk density varies from 0.42 to 0.9, shrinkage varies from 3.42 to 25.35, and specific surface area reaches values of 451.86 m2/g with 13% lignin and 270 m2/g with 27% lignin. High catalyst content improves lignin dissolution and increase shrinkage and bulk density of xerogels and bulk density. Lignin contributes to reducing shrinkage and specific surface area due to his compact and rigid structure. [ABSTRACT FROM AUTHOR]

Black liquor produced from pulping with a high value of chemical oxygen demand (COD) and biological oxygen demand (BOD) is highly harmful if discharged into the environment directly. One possible way to decrease the damage to the soil and water is to reuse the organic substances contained in it to cultivate yeasts for producing single-cell proteins (SCP) while reducing the COD. With this in mind, this study is devoted to treatment technology and the comprehensive utilization of black liquor. Various parameters were evaluated, and the COD of black liquor, initial pH, and nitrogen sources had significant influences on biomass and crude protein production. The research resulted in the maximum values of COD removal rate and crude protein production with 78.78 ±3.21% and 1.18 ±0.02 g/L achieved, respectively, under the optimized condition of black liquor concentration (60%), the recruitment of urea (0.5 g/L), initial pH (6.0), temperature (34 °C), shaking speed (180 rpm), and incubation time (36 h). Furthermore, this study provided a potential viable treatment of black liquor and revealed a feasible way to make full use of black liquor for the economical production of SCP. [ABSTRACT FROM AUTHOR]

The causticizing calcium carbonate (CCC) produced in the causticizing stage of the chemical recovery process in alkaline pulping of wheat straw has a high silicate content and is difficult to convert to calcium oxide in the lime kiln. The CCC can be utilized as a paper filler to avoid costly lime reburning, but the silicate content of the CCC can have a negative impact on the wet-end chemistry of the papermaking process. In this paper, the effect of the silicate content of the CCC filler on AKD sizing was investigated. CCC fillers of various silicate contents were prepared in the lab by causticizing green liquor from the soda pulping of wheat straw and were added to fiber suspensions at the wet end of the papermaking process. The results show that the impact of the CCC filler on AKD sizing was associated with its silicate content. As the silicate content increased, the specific surface area and negative charge density of the CCC particles markedly increased, resulting in more AKD adsorption onto the CCC particles instead of fibers. [ABSTRACT FROM AUTHOR]

The chemical composition of black liquors obtained from the soda-AQ pulping of birch ( Betula pendula) sawdust was studied as a function of cooking time, effective alkali content, and hot-water pretreatment of the sawdust prior to delignification. Special attention was paid on the formation of lignin-derived materials and low-molecular-mass carbohydrate-derived degradation products containing aliphatic carboxylic acids. In the case of the hot-water-pretreated feedstock, less acetic acid and formic acid and more nonvolatile hydroxy acids (especially monocarboxylic acids) were obtained. The observations can be interpreted as a result of the extensive removal of hemicelluloses during the hot-water pretreatment. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize the properties of pulp and paper manufactured from two agricultural residues namely, wheat straw ( Triticum aestivum L. em Thell.) and date palm midribs ( Phoenix dactylifera L.) widely available in Saudi Arabia by employing soda-anthraquinone (AQ) pulping process. Specimens from cedar wood ( Juniperus procera Hochst. ex Endl.) wood was also used as control samples. Chemical and the morphological characteristics of all three types of raw materials in addition to basic properties of hand sheets made from such resources were evaluated. The results indicated that wheat straw had the highest hemicellulose and ash values of 35% and 7% and the lowest lignin content value of 18%, respectively. The fibre length of the both palm fronds and wheat straw was lower than that of 2.2 mm which was found for J . procera . Overall strength properties of the handsheet made from two agricultural raw materials were significantly lower than those made from J . procera pulp. Wheat straw handsheets also had higher strength properties than those made from date palm midribs with an exception of their tear index. Based on the results of this study it appears that both types of raw materials, date palm midribs and wheat straw could have a potential to manufacture pulp and paper with accepted properties so that such underutilized species can be converted into value-added products. [ABSTRACT FROM AUTHOR]

The effect of electrocoagulation treatment was investigated on black liquor from soda-anthraquinone (AQ) pulping of wheat straw. Removal of phenol, chemical oxygen demand (COD), color, total suspended solids (TSS), total dissolved solids (TDS), and total solids (TS) from black liquor was investigated at different current densities by using aluminum electrodes at various electrolysis times (10, 25, 40, 55, and 70 min) and pH levels (3, 5, 7, 9, and 10.5). It was observed that at 16 V, electrolysis time of 55 min and current density of 61.8 mA/cm were sufficient for the removal of the pollutants. Energy consumption was evaluated as an important cost-relation parameter. Results showed that the electrocoagulation treatment reduced color intensity from the high initial value of 18,750 to 220 PCU. This was strongly influenced by the pH level of the wastewater. In addition, it was found that the removal efficiency increased with increasing of current density. The maximum efficiencies for removal were 98.8, 81, 80, 92, 61, and 68 % for color, phenol, COD, TSS, TDS, and TS, respectively. The lowest energy consumption values were obtained at neutral pH after 55 min. Electrocoagulation was found to be an effective, simple, and low-cost technique to treat black liquor. [ABSTRACT FROM AUTHOR]

In the alkaline decomposition of aβ-O-4type lignin model compound (erythro-guaiacylglycerol-β-guaiacyl ether, compound 1), an isomeric pair of C6C2enol-ether (2-methoxy-4-[2-(2-methoxyphenoxy)-vinyl]-phenol, compound 2) was detected as the main decomposition product with no trace of C6C3enol-ether (4-[3-hydroxy-1-(2-methoxyphenoxy)-propenyl]-2-methoxy-phenol, compound 3) or other dimers. In contrast, compound 2 was not detected in the alkaline decomposition products of compound 3. Under alkaline conditions, theγ-hydroxymethyl group of compound 3 was reduced to form 2-methoxy-4-[1-(2-methoxyphenoxy)-propenyl]-phenol (compound 4). In the HSQC analysis of soda lignin, the formation of substructures of C6C2type enol-ether (related to compound 2) was confirmed. However, no substructures related to compound 4, which could be formed if a substructure of C6C3type enol-ether was formed under alkaline conditions, were detected. Therefore, it could be concluded that C6C3type enol-ethers could not be intermediates of alkaline decomposition products of lignin. [ABSTRACT FROM PUBLISHER]

The aim of this research is to develop an enzymatic saccharification process of sago starch waste, with a small charge of cellulase. The waste contained a significant amount of residual starch, which was recovered as glucose by mild acid hydrolysis. The starch-free residue was subjected to soda-anthraquinone pulping to yield soda pulp and soda lignin. The lignin was converted to amphipathic lignin derivatives by the reaction with epoxylated polyethylene glycol analogues. The pulp was hydrolyzed with cellulase (Genencor GC220), with the amphipathic derivatives, to yield glucose. The lignin derivative-assisted, enzymatic saccharification was repeatedly conducted by reusing cellulase recovered by ultrafiltration from saccharification media. Saccharification efficiency with the derivatives was maintained at a high level even after the fourth run of saccharification, while the efficiency was remarkably decreased by repeated use of cellulase without additive. Thus, the amphipathic sago lignin derivatives enabled repeated use of cellulase for saccharification of sago starch waste. [ABSTRACT FROM AUTHOR]

Green liquor in the chemical recovery process of wheat straw pulping was treated with carbon dioxide to precipitate silicon. We report on the properties of causticized calcium carbonate (CCC) with different silicon contents, as well as its impact on paper quality when used as filler. The research results showed that silicon content had no significant effect on the crystal form of CCC, and all crystals were formed as calcite. Calcium silicate itself did not polymerize to form crystal in the course of causticization. Instead, silicon existed as a solid solution in CCC. The morphology of CCC changed gradually from amorphous to square with the decrease of silicon content. The brightness of CCC increased slightly and the average particle size tended to grow after removal of silicon. When 97% of silicon was removed and the average particle size reached 6.84 μm, the specific surface area and sedimentation volume decreased gradually as the desilication rate increased. When CCC was used as filler and silicon in CCC decreased, opacity remained nearly the same and brightness increased slightly; however, the Cobb value decreased significantly and the sizing efficiency obviously improved. When the silica content decreased to 3.2% the Cobb value was 27.7 g/m², which reached the standard for fine paper sizing. The tear strength increased gradually, while the tensile strength decreased with the reduction of silicon. Application: Understanding the properties of causticized calcium carbonate with different silicon content, as well as its impact on paper quality, can benefit papermakers seeking to reuse causticized calcium carbonate produced from the chemical recovery process of straw soda pulping. [ABSTRACT FROM AUTHOR]

The main goal of this study was to evaluate the potential of depithed bagasse for the production of printing and writing paper. Industrial whole bagasse was separated into two fractions: pith and depithed bagasse. The depithed bagasse was cooked by the soda process to two different degrees of delignification. The resulting pulps were fully bleached by the O-D*-(EP)-D sequence and characterized for their beatability, drainability, and physical-mechanical properties. Bleached soda pulps cooked to kappa 17.5 and 10.8 showed similar refinability and resistance to drainage, but the strength properties (tensile, burst, and tear) were slightly higher for the kappa 17.5 pulp at beating energy consumptions in the range of 2-7 W·h. We concluded that both pulps from depithed sugar cane bagasse would be suitable for the production of printing and writing paper grade pulps, but the higher kappa pulp is more economically attractive given its higher pulping yield, without significantly increasing the bleaching chemical demand. Application: The work shows the possibility of using a renewable raw material, such as sugar cane bagasse, for the production of pulp for printing and writing paper. [ABSTRACT FROM AUTHOR]

Fractionation of lignocellulosic biomass is an important process in producing biofuels. In this study, hot water extraction of corn stover hemicellulose was carried out at 150, 160, and 170 °C. Variations of sugar content in the hydrolysate under different holding time were detected. The contents of furfural and 5-hydroxymethyl-2-furaldehyde generated during the extraction were also determined. Results showed that the main composition of the hydrolysate was xylo-oligosaccharide; the yield of oligosaccharides first increased as holding time was prolonged. After extraction at 160 °C for 210 min, 70.2% of the total xylan was dissolved, with the generation of furfural (0.90 g/L) and 5- hydroxymethyl-2-furaldehyde (0.10 g/L). The effects of extraction on alkali pulping and bleaching were also investigated. Results indicated that soda-AQ pulp obtained from the extracted material had poorer tensile and burst strengths but better tear strength. [ABSTRACT FROM AUTHOR]

To reveal the structural changes of lignin during the soda-AQ cooking process and chemical bonds between lignin and xylan of wheat straw, 13C isotope-labeled technology was used in this study. First, 13C isotopelabeled xylose was injected into the living wheat straw. The success of 13C isotope-labeling was confirmed by the results of 13C abundance determination. Then, milled wood lignin-13C was extracted from wheat straw. The wheat straw, which had already been labeled by xylose-13C, was cooked by the soda-AQ process. Soda-AQ Lignin-13C and Residual Lignin-13C were extracted from black liquor and residual pulp. FT-IR, 13CNMR, and 2D HSQC NMR analyses indicated that all lignin preparations were HGS-type lignin. The main lignin linkages were ß-O-4' units, ß-ß' units, ß-5' units, and ß-1 units, with the highest content of ß-O-4'. Furthermore, 82.8% of ß-O-4' units, 77.2% of ß-ß' units, 75.4% of ß-5' units, and 75.4% of ß-1 units were degraded during the cooking process. LC bonds between lignin and xylan were at C2 and C5 positions of xylan. It was found that the C-2 position of xylan in wheat straw could be mainly connected to lignin by γ-ester bonds, and C-5 position of xylan in wheat straw was possibly linked with lignin by benzyl ether bonds. [ABSTRACT FROM AUTHOR]

Industrial hemp is a non-wood fiber material that can be used for papermaking due to a high yield of hemp raw material and high-quality physical properties of its pulp. Hemp is already used as a raw material for papermaking and other industrial productions. The chemical composition of hemp root bast (HRB) was analyzed. HRBs were pulped using a soda-anthraquinone (Soda-AQ) process and bleached with oxygen (O), chlorine dioxide (D), and alkali (E) using the bleaching sequence OD0ED1. The results showed that HRB can be a suitable raw material for papermaking; the HRB pulp had a high viscosity (893 mL g-1) and brightness (85.52% ISO-brightness). [ABSTRACT FROM AUTHOR]

Highlights: [•] The contents of cellulose, hemicelluloses and lignin in the sugar cane bagasse fractions varied significantly. [•] The pre-hydrolysis soda process improves the xylan removal but decreases pulp yield. [•] The pre-hydrolysis soda pulping followed by ECF bleaching is adequate for producing dissolving pulp from depithed bagasse. [ABSTRACT FROM AUTHOR]

Highlights: [•] Monoethanolamine (MEA) is a highly selective organic solvent for pulping of straw. [•] MEA pulping increases pulp yield by 10% compared to conventional soda pulping. [•] MEA pulping can be powerfully catalyzed by AQ which allows reducing the MEA charge drastically. [•] MEA straw pulps can be bleached in an environmentally friendly way to high brightness. [•] Papermaking properties of MEA pulps are fully comparable to those of soda/AQ pulps. [ABSTRACT FROM AUTHOR]

Phragmites karka, a common wetland grass, was delignified by the soda pulping process, and all the operating parameters were optimized. The effects of both anthraquinone and surfactant on pulp yield and kappa number at optimum pulping conditions were also investigated. The pulp was beaten at different beating levels to optimize different mechanical strength properties. A detailed morphological study of soda-AQ pulp of P. karka was conducted by scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the effects of hot water pre-extraction of depithed bagasse on the soda pulping and surface properties were studied. The conditions of hot water pre-extraction were: maximum temperature 170°C, heat-up time 90min, time at maximum temperature 10min, and solid to liquor ratio (S:L) 1:8. Consequently, the pre-extracted and un-extracted bagasse chips were subjected to soda pulping at 160°C for 1h with 11, 14 and 17% active alkali charge and an S:L of 1:5. The results showed that the hot water pre-extraction increased bagasse surface texture porosity by hemicellulose degradation. Therefore, the delignification was faster for pulping of pre-extracted samples. At a certain charge of alkali, pre-extracted samples showed higher screened yield and lower Kappa number. For instance, at 17% alkali charge, pre-extracted bagasse gave 11.3% higher pulp yield compared with the un-extracted ones. Inverse gas chromatography (IGC) results showed that the hot water pre-extraction changed the active sites on the bagasse surface, decreasing the dispersive energy and the basicity character, and affected the particle morphology. The pulping process decreased the hydrophobicity and the basicity of the bagasse surface. The surfaces of un-extracted and pre-extracted bagasse pulps had similar properties but different morphology. The pulps present higher surface area and permeability with more reactive capacity. [Copyright &y& Elsevier]

This study evaluates the effect of integrated solar-assisted advanced oxidation process (AOP) and biological treatment on the extent of degradation of effluents from chlorination (C) and first alkaline extraction (E) stages of soda pulp bleaching in agro-residue-based pulp and paper mill. Biodegradation of the effluents was attempted in suspended mode using activated sludge from the functional pulp and paper industry effluent treatment plant acclimatized to effluents in question. The photocatalytic treatment was employed using zinc oxide (ZnO) in slurry mode for decontamination of effluents in a batch manner and the degradation was evaluated in terms of reduction in chemical oxygen demand. The biological treatment (24 h) of C and E effluent resulted in 30 and 57 % of degradation, respectively. Solar-induced AOP of C and E effluents resulted in 53 and 43 % degradation under optimized conditions (2.5 g L ZnO at pH 8.0) after 6 h of exposure. For C effluent, a short duration of solar/ZnO (1 h) prior to biological treatment reduced the time required at biological step from 24 to 12 h for almost same extent (92 %) of degradation. However, sequential biological treatment (24 h) followed by solar/ZnO (2 h) resulted in 85.5 % degradation. In contrast, in the case of E effluent, sequential biological (24 h)-solar/ZnO (2 h) system effectively degrades effluent to 95.4 % as compared to 84.8 % degradation achieved in solar/ZnO (2 h)-biological treatment (24 h) system. In the present study, the sequencing of photocatalysis with the biological treatment is observably efficient and technically viable process for the complete mineralization of the effluents. [ABSTRACT FROM AUTHOR]

Two hydrophobic and one hydrophilic anthraquinone (AQ) polystyrene catalysts were tested under soda pulping conditions on thermomechanical fibers, and the results were evaluated based on commercial AQ. Hydrophobic and hydrophilic polymers had efficiency gains of 23%-28% and 57%, respectively, compared to AQ (100% efficiency). Hydrosolubility of AQ polymers played a major role in delignification efficiency, a property that allows a better contact with lignocellulosic fibers. Hydrophobic copolymers were stable under pulping conditions and preserved their catalytic effect entirely by contrast to the hydrophilic AQ, as demonstrated by recovery yields after pulping and catalytic action of the recovered copolymers. Studies on lignin models confirmed that the hydrophilic AQ polystyrene is a better catalyst under soda pulping conditions than the hydrophobic ones. It was demonstrated that AQ polystyrene polymers react with lignin models by electron transfer mechanisms. [ABSTRACT FROM AUTHOR]