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The corrosion and material evaluation study in (a) water‐based simulated black liquor and (b) water‐based simulated black liquor at super‐critical conditions was successful. The conclusion from the testing program was that the most resistant alloy for the defined conditions is the chromium‐rich carbon steel candidate P91 (UNS K91560). This is a type of creep strength‐enhanced ferritic alloy, which is steel designed to retain strength at high temperatures. The P91 abbreviation represents the material's chemical composition, that is, 9 wt% chromium (Cr) and 1 wt% molybdenum (Mo). Further work is required to conclude the corrosion resistance for the P91 quality at supercritical conditions in the welded condition and to better understand caustic corrosion mechanisms. [ABSTRACT FROM AUTHOR]

This study investigates the impact of lignin extraction on the rheological and combustion properties of high-solids bamboo kraft black liquor (BKBL), focusing on viscosity reduction and silicon interference mitigation. Lignin was extracted from BKBL using CO2 acid precipitation. The effects on viscosity, silicon content, calorific value, and Volumetric Isothermal Expansivity (VIE) were systematically analyzed. Extracting 25 % of lignin reduced the apparent viscosity of BKBL and achieved a 33 % desilication rate. However, this extraction also led to a proportional decrease in calorific value and VIE, with a 15 % extraction resulting in approximately 11 % and 13 % reductions, respectively. An extraction rate of 15–25 % is recommended to balance viscosity reduction and silicon removal with minimal impact on boiler combustion efficiency. This study provides practical insights into optimizing lignin extraction from BKBL, offering significant operational, economic, and environmental benefits for the bamboo kraft pulping industry. [ABSTRACT FROM AUTHOR]

In pulp mills, lags obscure the effect of upstream operations on downstream measurements. Here, we estimate lags in a Canadian pulp mill using autoregressive exogenous (ARX) models. First, we show that ARX models can approximate lags in a process simulation that resembles the liquor storage tanks in pulp mills, a major source of lag in the kraft recovery cycle. Then, we use ARX models to estimate the lagged effect of a change in species pulped on as-fired liquor heating value, viscosity, and boiling point rise. Additionally, we compare the predictions of the ARX models to autoregressive (AR) models and a persistence model. The estimated lags between a change in species and heating value (49 h) and boiling point rise (41 h) agree with a detailed simulation of the mill and are close to estimated hydraulic residence times, suggesting that the liquor tanks exhibit imperfect mixing. A lagged effect of species change on viscosity could not be identified. ARX and AR models produce similar predictions that are slightly better than those of a persistence model. Finally, we show that process measurements upstream of units characterized by large residence times will likely provide little benefit to prediction accuracy. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Paper-based materials made from cellulose have been sought after as a sustainable and inexpensive packaging option. However, the porous structure and high hydrophilicity of paper-based materials result in inadequate water and oil repellency, as well as a limited water vapor barrier. In this work, lignin nanoparticles (LNPs) were prepared using a high-speed homogenizer, and subsequently coated on base paper along with cationic starch to enhance its multi-barrier performance to facilitate the packaging application. The LNPs obtained through such a facile process formed stable colloidal dispersion in water, which exhibited excellent interfacial compatibility with cationic starch. During the coating process, a highly adhesive emulsion consisting of cationic starch and LNPs were coated on the surface of base paper, imparting good hydrophobic properties to the paper. The resulting paper material exhibited good water resistance (Cobb value of 37.5 g m−2), high oil resistance (Kit rating 9) and tensile strength (48.93 MPa). The reduction in water vapor transmission rate (WVTR) exceeds sixfold. This study provides a new avenue for the application of lignin in high-barrier, fluorine-free, water-and oil-resistant packaging materials.

To reduce energy consumption, a new pulping process called A-D-E-RC (acidification/desalination/electrolysis/recycle-cooking) was developed by a research group in Guangxi University of China. The present work focuses on the step of recycle cooking (RC) to further investigate the technical feasibility of A-D-E-RC methods. Golden bamboo grass was considered as fiber source material for pulp, and it was cooked with the acidic treating of wastewater from black liquor. Then, the pulp obtained from each cooking was made into paper to test the changes in its physical properties. As a result, the pulp yield increased from 43.9% to 50.2%, after re-using acidified black liquor, and the paper's tear index and tensile index were improved. Therefore, this study demonstrated the feasibility of recycle cooking (RC) fiber materials for pulp applied the acidic treating wastewater from black liquor, and thereby, it further identifies the technical feasibility of A-D-E-RC pulping methods.

Kraft pulping process is the foremost common pretreatment method utilized in pulp and paper businesses to break down the lignocellulosic linkages to urge cellulose and lignin separated. Due to higher degree of recuperation of the reagents utilized within the process of pulp production having higher cellulosic virtue, this technique rules over others since many decades. A factorial experiment may have star points and centre points added, offering three or five levels for each component. This is known as a central composite design, and it is utilised in response surface modelling. There are a few components to be considered in kraft pulping method which are temperature, retention time, % alkalinity, % sulfidity, and liquor to biomass stacking. The use of Na2S stands for a source of HS−, but too for an extra source of NaOH agreeing to the response included in this prepare. In spite of the fact that we have not taken those two components into thought, they can moreover be utilized in future inquire about. Thus, here, we utilized central composite plan to optimize our components. By taking temperature extend of 140–175 °C, time 20–80 min, and % alkalinity 10–20%, we have gotten diverse reactions of greatest bright absorbance wavelength and concentration information of black liquors. [ABSTRACT FROM AUTHOR]

Lignin, which contains aromatic phenols, is the second most abundant renewable biomass material in the world. It is the main byproduct of the paper industry and is characterized by abundant sources, renewability, and low cost. The present study focused on the extraction of lignin from poplar wood through a straightforward papermaking approach, thereafter utilizing the resultant black liquor containing lignin for synthesizing lignin-based phenolic resins. During the polymerization process, cobalt (Co) and nickel (Ni) species were introduced and, subsequently, a CoNi/biochar catalyst was obtained through pyrolysis in a nitrogen atmosphere. The prepared catalyst possessed rough spherical structures. The incorporation of Co and Ni enhanced charge redistribution, thereby imparting the catalyst with strong electron acceptance capabilities. The prepared lignin-based phenolic-resin-derived carbon was used for the electrochemical sensing of 2-nitrophenol. The limit of detection (LOD) for 2-nitrophenol was calculated to be 0.0132 µM, with good repeatability, stability, and selectivity. [ABSTRACT FROM AUTHOR]

ABSTRACT: The objective of this research was to extract lignin from Eucalyptus sp. kraft black liquor and to evaluate the influence of its addition on the properties of the lignin-phenol-formaldehyde adhesive. The adhesives were synthesized at different phenol mass percentages by lignin, called lignin-phenol-formaldehyde adhesives in the proportions of 25, 30, 50, 75 and 80%. The parameters evaluated in the adhesives were pH, total solid content, organic compound content, inorganic compound content, gelatinization time and adhesive behavior in the glue line. The pH ranged from 10.63 to 11.65. For the total solid content was found the value of 53 to 69 %. The contents of organic compounds ranged from 51 to 75% and inorganic from 25 to 49%. It was observed that with the addition of macromolecule in the adhesive formulation, the total and organic solid content was reduced proportionally while the inorganic solid was high. The gelatinization time was reduced due to the addition of lignin. The lower proportions of addition presented better penetration and fluidity in interface with the wood. The kraft lignin extracted from eucalyptus kraft black liquor is a great adhesive with potential to partially replace petroleum-derived phenol, with great potential for use and application in the aeronautical and automotive sectors, in the bonding process of structural parts.

The valorization of black liquor, a by-product produced in considerable quantities from the paper manufacturing processes, has demonstrated the effectiveness of thermal reconversion into pyrolysis gas, bio-oil, and bio-char, a sustainable approach placing the feedstock into a circular economy concept. The present study focused on developing disposal solutions through energy recovery via pyrolysis at 300 °C and 450 °C when lignite and nanomaterials (such as Cu-Zn-MCM-41, Ni-SBA-3, or Ni-SBA16) were used as catalysts. The results were compared to those of non-catalytic pyrolysis. The use of the Cu-Zn-MCM-41 catalyst proved to be efficient for pyrolysis gas production, reaching 55.22 vol% CH4. The increase in the calorific value of the pyrolysis gas was associated with the use of the Cu-Zn-MCM-41, showing a value of 42.23 MJ/m3 compared to that of the non-catalytic process, which yielded 39.56 MJ/m3. The bio-oil resulting from the pyrolysis with Cu-Zn-MCM-41 showed the highest energy value at 6457 kcal/kg compared to that obtained with the other two nanocatalysts, Ni-SBA-3 and Ni-SBA-16, as well as that of the raw material, which had a value of 3769 kcal/kg. The analysis of bio-char revealed no statistically significant differences when comparing the outcomes from using the various nanocatalysts, suggesting their minimal impact on the energy content. [ABSTRACT FROM AUTHOR]

Lignin is one of the most abundant bio‐aromatic molecular resources, but it is currently underutilized for energy production in the pulp and paper industry. Unlocking the full potential of lignin could have a significant impact on reducing environmental pollution, increasing the use of renewable resources, and achieving environmentally beneficial economic growth. However, effective lignin valorization requires viable and integrated reaction and separation processes to produce high value monomeric phenolics, such as vanillin and syringaldehyde. The aim of this short review is to summarize the studies on different separation methods of lignin derivatives obtained from black liquor, including extraction, membrane filtration, chromatographic separation, and the combination technologies. [ABSTRACT FROM AUTHOR]

In India, cow dung is widely utilized to create formulations that serve as effective plant growth enhancers with antimicrobial properties. The cow dung-derived handmade paper manufacturing process produces two waste-liquor streams, a Raw Liquor (RL) produced through the dewatering of the cow-dung slurry and a Black Liquor (BL) produced during the soda pulping of dewatered cow dung. The present study explored the potential of these waste streams to be used as plant biofertilizers for germination and cultivation of Vigna radiata seeds (mung bean, IPM-02-03 variety). An in vitro assay for seed germination efficiency and a pot study for plant growth promotion (PGP) activity were used to assess this potential. The in vitro assay demonstrated that nutrient-rich RL, with its 100% seed germination efficiency (better than the 85.7% of tap water) was an effective biofertilizer for seed germination. In contrast, BL yielded poor seed germination efficiency. The pot study showed that water irrigation led to good seed germination, survival, plant rooting and shooting, but it was probably deprived of nutrients for inducing good grain yields. When water was replaced with RL, it was able to replicate the results, but with good grain yields. In contrast, BL produced poorer germination, seed survival and PGP results. The poor biofertilization efficiency of BL was most probably due to the nutrient losses and toxic chemicals produced in the harsh pulping process. The results showed that RL, though considered a waste stream, is sufficiently nutrient-rich to act as an effective biofertilizer for germinating mung bean seeds and promoting plant growth and grain yields. [ABSTRACT FROM AUTHOR]

Currently, many research projects are focused on the conversion of renewable raw materials into chemicals and fuels. Lignocellulosic biomass is a raw material used for the production of bio-oils and black liquors. These biomass-derived fractions offer promising paths for the production of valuable chemical products. Various catalytic methods have been investigated for upgrading the biomass-derived fractions. Researchers are interested in the hydrodeoxygenation process (HDO); in this process, the oxygen groups are eliminated by breaking the C-O bonds and water as a product. Incorporating heterogeneous catalysts (i.e., noble metals, transition metals, and metal sulfides) improves this process. Most HDO review articles describe catalytic results for model phenolic compounds. However, there is also a need to investigate the catalytic activity of real biomass-derived fractions. This paper explains research results regarding the upgrading of lignin-derived fractions (i.e., black liquors) by HDO. The paper has been organized according to the type of heterogeneous catalyst and shows compelling results based on different experimental conditions. The final sections present an analysis of the documented results and outline perspectives about integrating lignin into the biorefinery framework. [ABSTRACT FROM AUTHOR]

Manganese- and nitrogen-doped carbon materials were produced using NaOH-activated wood char and wood-processing residues such as wood chips and black liquor and evaluated as oxygen reduction catalysts for further application in fuel cells or metal–air batteries. The elemental and chemical composition, with special attention given to types of nitrogen bonds and the structure, morphology, and porosity of the obtained catalyst materials were studied. The catalytic activity was assessed in an alkaline medium using the rotating-disk electrode method. It has been shown that synthesized and doped N-Mn catalytic materials based on biomass precursors with different chemical structures are a promising alternative to modern oxygen reduction catalysts based on precious metals. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A lab-scale gravity-driven bioreactor (GDB) was designed and constructed to evaluate the simultaneous treatment of black liquor and domestic wastewater. The GDB was operated with a mixture of black liquor and domestic wastewater at a ratio of 1:1 and maintained at an average organic loading rate of 1235 mg-COD/L-Day. The wastewater was fed to the primary sedimentation tank at a flow rate of approximately 12 mL/min and subsequently passed through serially connected anaerobic and aerobic chambers with the same flow rate. Each wastewater sample was allowed to undergo a hydraulic retention time of approximately 72 h, ensuring effective treatment. The GDB was actively operated for nine samples (W1–W9) at a weekly frequency. The entire process was conducted within the workstation's ambient temperature range of 30–35 °C to sustain microbial activity and treatment efficiency in an open environment. The performance of the GDB was evaluated in terms of various pollution indicators, including COD, BOD5, lignin removal, TDS, TSS, EC, PO43−, SO42−, microbial load (CFU/mL and MPN index), total nitrogen, and color reduction. The results showed that the GDB achieved promising treatment efficiencies: 84.5% for COD, 71.80% for BOD5, 82.8% for TDS, 100% for TSS, 74.71% for E.C., 67.25% for PO43−, 81% for SO42−, and 69.36% for TN. Additionally, about 80% reduction in lignin content and 57% color reduction were observed after the treatment. The GDB substantially reduced microbial load in CFU/mL (77.98%) and MPN (90%). This study marks the first to report on wastewater treatment from two different sources (black liquor and domestic wastewater) using a simple GDB design. Furthermore, it highlights the GDB's potential as a cost-effective, environmentally friendly, and efficient solution for wastewater treatment, with no need for supplementary chemical or physical agents and zero operational costs. [ABSTRACT FROM AUTHOR]

In our previous study, we demonstrated that Eucalyptus dunnii samples containing high calcium content show inferior pulping properties concerning delignification and polysaccharide degradation. This led us to investigate alternative methods for improving the pulping process of these samples. In the present work, we evaluated the effects of incorporating black and green liquors into the Eucalyptus dunnii chips before kraft pulping, aiming to enhance the pulping process and overcome the negative impact of high calcium content. The addition of both black and green liquors resulted in specific enhancements, with the green liquor having a more significant impact on the pulping process. Even wood samples with the highest calcium content demonstrated satisfactory pulping results when treated with green liquor. Delignification occurred more rapidly, and selectivity was higher for samples pre-treated with green liquor before kraft pulping. Moreover, calcium tended to follow the fiber under these conditions rather than being released into the black liquor, which may contribute to the improved pulping performance. Subsequent bleaching tests revealed that the bleachability of green liquor-treated pulp was nearly identical to that of a control pulp, while maintaining a higher viscosity. This suggests that incorporating green liquor into the pre-treatment process not only improves the pulping performance of Eucalyptus dunnii samples with high calcium content but also maintains desirable bleachability characteristics. To better understand the underlying mechanisms of these findings, we discuss the potential chemical explanations behind the observed improvements. [ABSTRACT FROM AUTHOR]

The current investigation concerns with preparation eco-friendly and cost-effective adsorbent (mesoporous silica nanoparticles (SBL)) based on black liquor (BL) containing lignin derived from sugarcane bagasse and combining it with sodium silicate derived from blast furnace slag (BFS) for thorium adsorption. Thorium ions were adsorbed from an aqueous solution using the synthesized bio-sorbent (SBL), which was then assessed by X-ray diffraction, BET surface area analysis, scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX), and Fourier transforms infrared spectroscopy (FTIR). Th(IV) sorption properties, including the pH effect, uptake rate, and sorption isotherms across various temperatures were investigated. The maximum sorption capacity of Th(IV) on SBL is 158.88 mg/L at pH value of 4328 K, and 60 min contact time. We demonstrated that the adsorption processes comport well with pseudo-second-order and Langmuir adsorption models considering the kinetics and equilibrium data. According to thermodynamic inspections results, the Th(IV) adsorption process exhibited endothermic and random behavior suggested by positive ΔH° and ΔS° values, while the negative ΔG° values indicated a spontaneous sorption process. The maximum Th(IV) desorption from the loaded SBL (Th/SBL) was carried out at 0.25 M of NaHCO3 and 60 min of contact. Sorption/desorption processes have five successive cycles. Finally, this study suggests that the recycling of BFS and BL can be exploited for the procurement of a promising Th(IV) adsorbents. [ABSTRACT FROM AUTHOR]

A techno-economic assessment and environmental and social sustainability assessments of novel Fischer–Tropsch (FT) biodiesel production from the wet and dry gasification of biomass-based residue streams (bark and black liquor from pulp production) for transport applications are presented. A typical French kraft pulp mill serves as the reference case and large-scale biofuel-production-process integration is explored. Relatively low greenhouse gas emission levels can be obtained for the FT biodiesel (total span: 16–83 g CO2eq/MJ in the assessed EU countries). Actual process configuration and low-carbon electricity are critical for overall performance. The site-specific social assessment indicates an overall positive social effect for local community, value chain actors, and society. Important social aspects include (i) job creation potential, (ii) economic development through job creation and new business opportunities, and (iii) health and safety for workers. For social risks, the country of implementation is important. Heat and electricity use are the key contributors to social impacts. The estimated production cost for biobased crude oil is about 13 €/GJ, and it is 14 €/GJ (0.47 €/L or 50 €/MWh) for the FT biodiesel. However, there are uncertainties, i.e., due to the low technology readiness level of the gasification technologies, especially wet gasification. However, the studied concept may provide substantial GHG reduction compared to fossil diesel at a relatively low cost. [ABSTRACT FROM AUTHOR]

The valorization of the black liquor produced during the chemical pulping of wheat straw is the key to the sustainable use of this abundant agricultural waste. However, the silica problem has hampered the recovery process. Herein, nanoprecipitation technology was used to produce lignin nanoparticles (LNPs) from wheat straw black liquor using γ-valerolactone (GVL) as a solvent and water as an anti-solvent. The results showed that a uniform, well-dispersed, and stable LNP was produced. The particle size and Zeta potential of 161 nm and −24 mV of the LNP suspension were obtained at a GVL concentration of 87%. The chemical structure and bonding of the lignin were adequately preserved after nanoprecipitation based on two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC NMR) spectroscopy, Fourier transform infrared (FTIR) analysis, and thermal stability was improved based on thermogravimetric analysis. In addition, the abundant phenolic hydroxyl groups of LNP quantified by 31P-NMR analysis are beneficial for chemical cross-linking and modification. This work not only achieved the valorization of wheat straw black liquor but also opened up a new avenue for advanced nanomaterials. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The inorganic sulfur compounds that are used as pulping agents in the production of pulp and paper from wood are converted into a variety of sulfur species during processing. How sulfur is allocated to different streams and products in a pulp mill is relevant for efficient mill operation and to avoid harmful emissions. Pulping liquors are a highly challenging and potentially destructive sample matrix. We describe a thin-layer chromatographic method for the direct quantification of elemental sulfur in pulping liquors. The liquors are spotted (not sprayed!) directly onto the plate without prior purification, extraction, or workup. Sulfur is then eluted with cyclo-hexane and detected by densitometry at 285 nm or fluorescence quenching close to the solvent front. The method was validated for a calibrated range from 60 to 2000 ng sulfur on plate. The limit of detection was determined at 20 ng; measurement uncertainty was about 20%. With this method, 27–54 mg/L elemental sulfur were found in Kraft pulping liquors, which corresponds to 0.24–0.48% of the total sulfur in these samples. [ABSTRACT FROM AUTHOR]

In the current research, lignin was successfully extracted from industrial waste Kraft black liquor using acid precipitation method. In the following step, powdered carbon was sensitized through H3PO4-chemical activation method. The effects of synthesis parameters including activation temperature (T) within the range of 400-600 ⁰C and two H3PO4/Lignin mass ratio (R) of 2 and 3 on activated carbon (AC) structure were investigated. To study the physical and morphological properties of the sensitized carbons, BET, SEM, and FTIR methods were used. The potential application of synthesized ACs was investigated by measuring their adsorption capacity in adsorption process of Methylene blue (MB) from aqueous solution. The AC sensitized at R=2 and T= 500 ⁰C (AC-2-500) showed the highest specific surface area (1573.31 m2/g) and the pore volume (0.89 cm3/g) as well as the highest adsorption capacity of MB. This adsorbent was applied in the equilibrium adsorption experiments and kinetic description. The results from kinetic experiments and adsorption isotherms indicated that the pseudo-first-order model and Langmuir model were in the most correspondence with the experimental data. Maximum adsorption capacity was 188 mg/g. The study proved that a high potential for conversion of black liquor to greatly porous Lignin-based adsorbents. Moreover, the considerable maximum adsorption capacity suggested that a noteworthy potential of Lignin-based AC for wastewater treatment.

The paper industry faces two critical challenges: the scarcity of raw materials and the environmental impact of chemical waste pollution. Addressing the first challenge involves harnessing alternative, sustainable raw materials, while the second challenge can be mitigated through the adoption of bio-bleaching processes, which significantly reduce chemical consumption while enhancing paper brightness and quality. This study proposes a solution to both challenges by using non-woody Calotropis procera (Ankara) and a xylanase-producing microbial consortium for sustainable handmade paper production, a combination not extensively explored in prior research. To evaluate this approach, the process was divided into three stages. In stage I, Ankara fibre was pulped through open hot digestion. In stage II, the pulp was subjected to bio-bleaching in two experimental setups: Set I (without sucrose) and Set II (with sucrose) for 5 days. In stage III, chemical bleaching was used to improve the final brightness of the treated pulps. A novel comparison was made between the bio-bleaching efficiency of an individual isolate g5 (BI) and a bacterial consortium (BC). This research highlighted that bio-bleaching with the consortium effectively removed lignin (140±60 mg/l) and colour (1830±50 PCU), especially in the presence of sucrose, compared to using a single xylanase isolate. Pulp residue/filtrate collected at each stage was estimated based on parameters such as colour and lignin content. After stage III (chemical bleaching), the release of colour and lignin in pulp filtrate was higher in BI compared to BC, indicating the consortium's effectiveness during bio-bleaching, which leaves fewer degradable lignin structures for the chemical bleaching stage. Papers crafted from consortium-treated pulp also exhibited higher brightness than those treated with the isolate. This study reveals the synergistic effect of microbial consortia, leading to more efficient lignin degradation and enhanced bio-bleaching capabilities, supporting the development of greener industrial processes. Ultimately, this study demonstrates a unique and eco-friendly approach to papermaking, combining C. procera and enzymatic bio-bleaching to reduce dependency on hazardous chemicals and support sustainable industry practices.

The object of research is the black liquor of the alkaline pulping sample Paulownia Clone in Vitro 112® with active alkali consumption of 14, 18 and 22 % in Na2O units from the mass of completely dry raw materials. The problem solved in the work is related to the formation of waste in the form of black liquor during pulp production. It is noted that as a result of the production of 1 ton of cellulose, up to 7 tons of black liquor is formed. In the course of the work, an analysis of the total titrated and active alkalinity in the white and black liquor after cooking paulownia wood was carried out, and the pH value was determined. The dependence of the content of dry substances in black liquor on the consumption of active alkali, the duration of cooking, the presence of a catalyst, and the final temperature of the delignification process is given. The amount of organic and mineral components of dry substances of black liquor per 1 ton of air-dry fibrous semi-finished products was calculated. It was established that with an increase in temperature by 20 °C (from 150 to 170 °C) and a duration of approximately 1.5 times (from 60 to 90 min and from 90 to 150 min), with the same consumption of active alkali and the use of a catalyst in the conditions after sodium pulping, the content of dry substances in the black liquor increases by 1.5–3 %. This regularity is explained by the transition into the solution of a greater number of dissolution products of lignin, hemicelluloses, and mineral substances. Estimated values for the content of mineral and organic substances in black liquor after cooking paulownia wood for a duration of 150 min and a final temperature of 170 °C at different consumptions of active alkali and the use of catalysts in the form of anthraquinone and ethyl alcohol are within the range of 1024–1518 kg per 1 ton dry pulps of normal yield and can be used in practice. The obtained results can be used to form an assessment of the black liquor as an additional resource potential for the economy of production. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Lignin, which contains aromatic phenols, is the second most abundant renewable biomass material in the world. It is the main byproduct of the paper industry and is characterized by abundant sources, renewability, and low cost. The present study focused on the extraction of lignin from poplar wood through a straightforward papermaking approach, thereafter utilizing the resultant black liquor containing lignin for synthesizing lignin-based phenolic resins. During the polymerization process, cobalt (Co) and nickel (Ni) species were introduced and, subsequently, a CoNi/biochar catalyst was obtained through pyrolysis in a nitrogen atmosphere. The prepared catalyst possessed rough spherical structures. The incorporation of Co and Ni enhanced charge redistribution, thereby imparting the catalyst with strong electron acceptance capabilities. The prepared lignin-based phenolic-resin-derived carbon was used for the electrochemical sensing of 2-nitrophenol. The limit of detection (LOD) for 2-nitrophenol was calculated to be 0.0132 µM, with good repeatability, stability, and selectivity.

Wheat straws are a globally abundant agro-waste that may play a critical role in the global transition from single-use plastics to green materials as an inexpensive and renewable raw material. Vast amounts of wastewater are produced during the technological process of wheat straw-cellulose/hemicellulose conversion. In this context, this work focuses on wastewater decolorization via activated carbon adsorption. A set of carefully planned experiments enabled the identification of a model that described the relationship between the system's outputs and parameters. While process optimization is frequently connected with identifying process parameters that improve efficiency, this work employed a multi-objective optimization approach from both a technological and economic aspect. Nondominated sorting genetic algorithm versions II and III—NSGA-II and NSGA-III algorithms—were applied. As objectives, maximum efficiency and minimum cost per experiment were followed in different scenarios using pseudoweights and trade-off metrics. When optimizing only the efficiency, the results indicated a 95.54% decolorization yield, costing 0.1228 Euro/experiment, and when considering both the efficiency and cost, different solutions were obtained. The lowest cost was 0.0619, with a 74.42% decolorization. These findings indicate that incorporating an economic perspective into the optimization procedure can improve cost estimation and facilitate managerial decision-making. [ABSTRACT FROM AUTHOR]

The delignification of birch chips during kraft pulping was investigated, targeting both the impregnation and cooking steps. Wood chips were impregnated using white liquor, white liquor + NaCl, water or NaCl aqueous solution. Then, the chips were cooked in batch autoclaves applying the same constant composition cooking conditions for all samples. Pulp and two fractions of black liquor (bulk liquor and centrifuged liquor representing the liquor inside the wood chips and fibers) were collected after different pulping times and analyzed for lignin and carbohydrate content. The dissolved wood components were precipitated from selected samples and characterized with respect to composition, molecular weight distribution and structural motifs. Cooking chemicals in the impregnation liquors led to faster delignification and xylan removal during cooking. Higher contents of lignin and xylan were measured in the lumen than in the bulk. The concentration profiles also showed accumulation of dissolved material in the lumen over time, suggesting significant mass transport limitation from lumen to bulk. Further analysis revealed higher fragmentation/degradation of dissolved material with increasing pulping time and in the bulk when compared to the lumen liquor, as demonstrated by the lower molecular weights and the changes in chemical shifts in the NMR spectra. [ABSTRACT FROM AUTHOR]

Despite black liquor's (BL) renown as a difficult-to-manage contaminant in the pulp and paper industry, BL has been found as a viable alternative material for adhesive formulation due to its high lignin content. Nevertheless, modification is required to enhance lignin's reactivity, and there is currently a lack of study focusing on this aspect for BL-lignin. This study aims to increase the phenolic hydroxyl content of BL-lignin by phenolation. After being phenolated at lignin to phenol ratio of 1:1, at a temperature of 100°C for 110 minutes, and with the addition of 8% sulfuric acid (H2SO4) as a catalyst, the phenolic hydroxyl content improved by 51.5%. The results of Fourier transform infrared spectroscopy (FTIR), UV/Vis spectrophotometry, proton nuclear magnetic resonance (¹H-NMR), thermogravimetrydifferential scanning calorimetry (TG-DSC), and its differential curve showed that the structural change in phenolated lignin opened up more active sites, implying that this lignin could be a good substitute for phenol in phenol-formaldehyde resin manufacturing. [ABSTRACT FROM AUTHOR]

Soda black liquor lignin is extracted from wood chips during the soda pulping process and ends up in the residual pulping liquor after brownstock washing. This liquor is commonly concentrated from approximately 15–20% to 70–80% solids which can be used as fuel to replace fossil fuel. In this work, the effect of temperature, pH, and solids content as process variables on the viscosity is analyzed. The viscosity of black liquor generated from soda pulping of wheat straw was optimized using Box-Behnken design (BBD) response surface method with numerical optimization technique. The results show that they have significant influence on the viscosity of black liquor. The experimentally observed data was analyzed through ANOVA. It is observed that the best optimum conditions for minimum viscosity (0.055 mPas) of black liquor were temperature (343 K), pH (7), and solids content (37%) respectively. The multiple regression analysis was used to develop second-order polynomial model equation, which fitted well and predicted the experimentally observed data within acceptable limits. The value of regression coefficient (R2) was high as near to unity. The viscosity is sensitive function of temperature, pH, and solids content. The black liquor viscosity plays major role on effectiveness of all operations used to process the black liquor through storage tank, multiple effect evaporators, concentrator, and its firing in the chemical recovery furnace. This study may be contributed for process equipment design and energy efficient operations of paper mill. [ABSTRACT FROM AUTHOR]

Rapid treatment processing for corn stover and black liquor is of the utmost importance with the boom in China's agriculture sector. Aerobic fermentation composting via microbial/black liquor inoculation is superior to traditional composting with enhanced compost maturity and accelerated organic matter degradation. This research aimed to investigate the feasibility of black liquor addition and the effect of microbial/black liquor inoculation on the chemical composition and physiochemical and biological parameters for compost quality assessment. Results indicated that both the microbial/black liquor and the black liquor inoculation improved the heating rate. After composting for 18 days, the C contents and H contents were decreased to 44.29 ± 0.19% and 5.98 ± 0.05%, while the O contents and N contents were increased to 45.25 ± 0.15% and 3.48 ± 0.01%, which is consistent with the results of elemental analysis. This result indicated that black liquor and microbial inoculations accelerated the formation of nitrogen structures and recalcitrant nitrogenous oxygenated compounds. The FTIR analysis of four treatments confirmed that the microbial/black liquor inoculation could promote lignocellulose degradation and lignin degradation in subsequent composting. 16S rRNA sequencing revealed Deinooccola, Gemmatimonadota, and Chloroflexi as the predominant bacteria. The study suggested corm stover/black liquor composting as a promising technique for rapid and enhanced quality compost production. [ABSTRACT FROM AUTHOR]

Black-liquor-thickening in an integrated multi-effect evaporation plant consumes substantial amounts of steam produced in pulp and paper mills, and its efficient operation is, thus, crucial. Industrial applications of heat pumps in the pulp and paper industry, especially in black liquor evaporation, show promise in terms of cutting energy consumption and in decarbonizing this industrial branch. Modelling of such a plant includes momentum, heat and mass transfer issues, enriched with black liquor material specification. An existing black liquor evaporation plant which thickens inlet black liquor from 17% to 75% wt. dry solids with a dry solid flow of 2500 tonnes per day is considered. It already includes a MVR (mechanical vapor recompression) pre-evaporator as well as water-condensate stripping columns. A mathematical model of this plant is created in a Matlab environment and, after verification of obtained results, it serves for analyses of possible plant modifications. Among the modification options, installation of a second MVR is modeled and its impact on the whole plant is examined. As a result, a differential (marginal) change in steam and electricity consumed in the plant is obtained. Model results indicate the possibility of a reduction of process steam consumption of around 10 tonnes per hour and an increase in electricity consumption of 600 kW. A favorable simple payback period of 2.5 years can be expected for the considered investment. [ABSTRACT FROM AUTHOR]

This study developed an efficient and green method for isolating and purifying lignin from black liquor (BL) using deep eutectic solvents (DESs). After the short and mild process (700 W microwave-assisted, 100 °C, DES: BL 1:5 (v: v), 30 min) using optimized DES (lactic acid (LA): choline chloride (ChCl) 10:1, molar ratio), the yield and purity of lignin obtained from 100 mL BL was 1.58 g and 88.12%, respectively, which was more efficient than the results of 1.18 g and 78.54% of the conventional process. Furthermore, more than 95% of initial results were obtained after three cycles. The composition and structure of DESs and conventionally purified lignin were slightly different. The solvent costs for both processes were also evaluated, showing that the DES process has great potential to replace traditional bulky and environmentally unfriendly procedures for lignin isolation and purification and to help develop new strategies for the potential added value of lignin. [ABSTRACT FROM AUTHOR]

In the current research, lignin was successfully extracted from industrial waste Kraft black liquor using the acid precipitation method. In the following step, powdered carbon was synthesized through the H3PO4- chemical activation method. The effects of synthesis parameters, including activation temperature (T) within the range of 400-600 °C and two H3PO4/Lignin mass ratios (R) of 2 and 3 on activated carbon (AC) structure, were investigated. The physical and morphological properties of the ACs were obtained through BET, SEM, and FTIR analyses. The potential application of ACs was studied by measuring their adsorption capacity in the adsorption process of Methylene blue (MB) from an aqueous solution. The sensitized AC at R=2, and T= 500 °C (AC-2-500) showed the highest specific surface area (1573.31 m2/g) and the pore volume (0.89 cm3/g), as well as the highest adsorption capacity of MB. This adsorbent was applied in the equilibrium adsorption experiments and kinetic description. The results from kinetic experiments and adsorption isotherms indicated that the pseudo-first-order model and Langmuir model were in correspondence with the experimental data most. The maximum adsorption capacity was 188 mg/g. The study proved there is a high potential for the conversion of black liquor to greatly porous Lignin-based adsorbents. Moreover, the considerable maximum adsorption capacity suggested a significant potential of Lignin-based AC for wastewater treatment. [ABSTRACT FROM AUTHOR]

Waste is generated in the form of black liquor during pulp processing. Furthermore, lignin, the main ingredient of black liquor, contains a phenylpropanoid compound with prebiotic and antimicrobial activity. Also, it is a component of lignocellulose that has prebiotic and antimicrobial activity effects due to its indigestible nature and it comprises phenylpropanoid components. Therefore, this study examines and identifies the lignin purification and test results of its prebiotic activity. The technique used to identify lignin fraction is called Thin Layer Chromatography (TLC) and Gas Chromatography-Mass Spectrometry (GC-MS) plates. Prebiotic activity tests were performed using the calculation of total bacteria on the growth of Lactobacillus casei. The results showed that the purification process using CHCl3, 3 % MeOH:CHCl3, 20 % MeOH:CHCl3, and MeOH yielded 10.68 %, 6.34 %, 11.38 % 44.85 %, respectively. The 3 % MeOH:CHCl3 fraction contained benzaldehyde, 4- hydroxy-3,5- dimethoxy, 1-methylbutyl hexadecanoate, oleic acid, and di-2-ethylhexyl phthalate. The 3 % MeOH:CHCl3 fractionate with a concentration of 15 % also showed a prebiotic activity for L. casei at 6.1 x 102 colonies/mL.

The solubility of sodium oxalate was measured in kraft black liquors at temperatures of 115 °C to 140 °C with dry solid contents of 45% to 70%. The composition of black liquors studied were varied with respect to sodium concentration by addition of sodium salts. The solubility of sodium oxalate increased with increasing temperature and decreased with increasing liquor dry solid contents. The solubility data showed no dependence on the liquor composition at a constant concentration of sodium. A mathematical expression was derived and validated from the experimental data at the conditions investigated to predict the solubility of sodium oxalate as a function of temperature and sodium concentration. An application to assess the solubility and precipitation risk of sodium oxalate is demonstrated in seven evaporator bodies using the newly derived models.

Lignin characteristics are significantly affected by kraft processing and isolation conditions. In the studies carried out in this context, commercial lignins or isolated lignins from industrial black solutions are generally preferred. In this study, in order to conduct more comprehensive research, three lignin samples were isolated from kraft black liquor obtained from laboratory cooking trials of pine, poplar, and wheat straw chips, representing softwoods, hardwoods, and annual plants, respectively, according to efficient pulping studies. In addition, another lignin-containing industrial waste was provided from a pulp mill (OBL). The acidification method was applied for isolating lignin from black liquor samples. After isolating the lignin samples from different sources, they were characterized and compared with the commercially available kraft lignin sample (Indulin AT). Total phenolic groups, carboxyl groups, purity, functional groups, nitrobenzene oxidation products, molecular weight, thermal stability, and element contents were analyzed. The isolated lignin samples (except wheat straw) were as pure as commercial lignin. Since the wheat straw was agricultural waste and an annual plant, inorganic elements such as P, K, and Si were more abundant than in the other samples. However, the polydispersity and molecular weight of all of the isolated lignin samples were higher than those of commercial lignin. Because the ash contents of the lignin samples for pine, poplar, OBL, and indulin AT were between 1 and 3%, they can be used for high-value applications. In particular, despite some disadvantages, wheat straw lignin has greater potential for use in extruders than softwood lignins due to their syringyl content. [ABSTRACT FROM AUTHOR]

The effluents generated in the paper industry, such as black liquor, have a high content of lignin and other toxic components; however, they represent a source of lignin-degrading bacteria with biotechnological potential. Therefore, the present study aimed to isolate and identify lignin-degrading bacteria species in paper mill sludge. A primary isolation was carried out from samples of sludge present in environments around a paper company located in the province of Ascope (Peru). Bacteria selection was made by the degradation of Lignin Kraft as the only carbon source in a solid medium. Finally, the laccase activity (Um-L−1) of each selected bacteria was determined by oxidation of 2,2′-azinobis-(3-etilbencenotiazolina-6-sulfonate) (ABTS). Bacterial species with laccase activity were identified by molecular biology techniques. Seven species of bacteria with laccase activity and the ability to degrade lignin were identified. The bacteria Agrobacterium tumefasciens (2), Klebsiella grimontii (1), and Beijeinckia fluminensis (1) were reported for first time. K. grimowntii and B. fluminensis presented the highest laccase activity, with values of 0.319 ± 0.005 UmL−1 and 0.329 ± 0.004 UmL−1, respectively. In conclusion, paper mill sludge may represent a source of lignin-degrading bacteria with laccase activity, and they could have potential biotechnological applications. [ABSTRACT FROM AUTHOR]

In this work, the wastewater obtained from the hydrothermal liquefaction of black liquor was treated and valorized for hydrogen production by supercritical water gasification (SCWG). The influence of the main process parameters on the conversion yield was studied. The experiments were conducted at three different temperatures (below and above the critical point of water): 350 °C, 450 °C and 600 °C. The results showed that by increasing the temperature from 350 °C to 600 °C, the total gas yield was highly improved (from 1.9 mol gas/kg of dried feedstock to 13.1 mol gas/kg of dried feedstock). The H2 composition was higher than that of CH4 and CO2 at 600 °C, and the HHV of the obtained gas was 61.2 MJ/kg. The total organic carbon (TOC) removal efficiency was also improved by increasing the temperature, indicating that the SCWG process could be used for both applications: (i) for wastewater treatment; (ii) for producing a high calorific gas. The experiments with the Raney-nickel catalyst were performed in order to study the catalyst's influence on the conversion yield. The results indicated that the catalyst enhances carbon conversion and gas production from mild to higher temperatures. The maximum total gas yield obtained with this catalyst was 32.4 mol gas/kg of dried feedstock at 600 °C, which is 2.5 times higher than that obtained at the same operating conditions without a catalyst. The H2 yield and the HHV of the obtained gas with the catalyst were 20.98 mol gas/kg dried feedstock and 80.2 MJ/kg, respectively. However, the major contribution of the catalytic SCWG process was the improvement of the total gas yield at mild operating temperatures (450 °C), and the obtained performance was even higher than that obtained at 600 °C without catalyst (17.81 mol gas/kg dried feedstock and 13.1 mol gas/kg dried feedstock, respectively). This is a sustainable approach for treating wastewater at mild temperatures by catalytic SCWG. [ABSTRACT FROM AUTHOR]

Herein, we present a synthesis route for high-efficiency nitrogen-doped carbon materials using kraft pulping residue, black liquor, and wood charcoal as carbon sources. The synthesized nitrogen-doped carbon materials, based on black liquor and its mixture with wood charcoal, exhibited high specific surface areas (SSAs) of 2481 and 2690 m2 g−1, respectively, as well as a high volume of mesopores with an average size of 2.9–4.6 nm. The nitrogen content was approximately 3–4 at% in the synthesized nitrogen-doped carbon materials. A specific capacitance of approximately 81–142 F g−1 was achieved in a 1 M Na2SO4 aqueous solution at a current density of 0.2 A g−1. In addition, the specific capacitance retention was 99% after 1000 cycles, indicating good electrochemical stability. [ABSTRACT FROM AUTHOR]

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In this study, selective extraction towards ionic liquid trihexyltetradecylphosphonium chloride ([P66614]Cl) of lignin residues, polysaccharides and organic acids present in black liquor (BL), the main principal wastewater of pulping industry was studied. With the objective of finding optimized conditions allowing to extract lignin residues while polysaccharides and organic acids remain in aqueous solution, a design of experiments approach based on a response surface methodology was used. Three continuous factors, namely initial pH varying from 9 to 13.5, dilution of BL varying from 5 to 20 and volumetric ratio of black liquor vs. ionic liquid RV., varying from 1 to 19, were investigated. Concentration of lignin residues, polysaccharides and organic acids were measured using Folin‐Ciocalteu method, the anthrone method and HPLC, respectively. Results showed that a multi‐response optimization led to the extraction of 84.8 % of lignin residues, 66.0 % of polysaccharides, and no extraction of OA under optimised conditions. [ABSTRACT FROM AUTHOR]

Lignin is a natural biopolymer with a complex three-dimensional network and it is rich in phenol, making it a good candidate for the production of bio-based polyphenol material. This study attempts to characterize the properties of green phenol-formaldehyde (PF) resins produced through phenol substitution by the phenolated lignin (PL) and bio-oil (BO), extracted from oil palm empty fruit bunch black liquor. Mixtures of PF with varied substitution rates of PL and BO were prepared by heating a mixture of phenol–phenol substitute with 30 wt.% NaOH and 80% formaldehyde solution at 94 °C for 15 min. After that, the temperature was reduced to 80 °C before the remaining 20% formaldehyde solution was added. The reaction was carried out by heating the mixture to 94 °C once more, holding it for 25 min, and then rapidly lowering the temperature to 60 °C, to produce the PL−PF or BO−PF resins. The modified resins were then tested for pH, viscosity, solid content, FTIR, and TGA. Results revealed that the substitution of 5% PL into PF resins is enough to improve its physical properties. The PL−PF resin production process was also deemed environmentally beneficial, as it met 7 of the 8 Green Chemistry Principle evaluation criteria. [ABSTRACT FROM AUTHOR]

Currently, many research projects are focused on the conversion of renewable raw materials into chemicals and fuels. Lignocellulosic biomass is a raw material used for the production of bio-oils and black liquors. These biomass-derived fractions offer promising paths for the production of valuable chemical products. Various catalytic methods have been investigated for upgrading the biomass-derived fractions. Researchers are interested in the hydrodeoxygenation process (HDO); in this process, the oxygen groups are eliminated by breaking the C-O bonds and water as a product. Incorporating heterogeneous catalysts (i.e., noble metals, transition metals, and metal sulfides) improves this process. Most HDO review articles describe catalytic results for model phenolic compounds. However, there is also a need to investigate the catalytic activity of real biomass-derived fractions. This paper explains research results regarding the upgrading of lignin-derived fractions (i.e., black liquors) by HDO. The paper has been organized according to the type of heterogeneous catalyst and shows compelling results based on different experimental conditions. The final sections present an analysis of the documented results and outline perspectives about integrating lignin into the biorefinery framework.

Manganese- and nitrogen-doped carbon materials were produced using NaOH-activated wood char and wood-processing residues such as wood chips and black liquor and evaluated as oxygen reduction catalysts for further application in fuel cells or metal–air batteries. The elemental and chemical composition, with special attention given to types of nitrogen bonds and the structure, morphology, and porosity of the obtained catalyst materials were studied. The catalytic activity was assessed in an alkaline medium using the rotating-disk electrode method. It has been shown that synthesized and doped N-Mn catalytic materials based on biomass precursors with different chemical structures are a promising alternative to modern oxygen reduction catalysts based on precious metals.