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The growing demand for effective and environmentally friendly phenol removal methods has led to a growing interest in investigating the potential of using biomass-derived activated carbon. This research investigated the absorption process of phenol from wastewater using activated carbon adsorbents and activated carbon modified with copper in a batch system. Activated carbon was obtained from paper mill black liquor. The pore structure and morphology of unmodified and modified samples were investigated by BET and SEM. Modifying activated carbon with copper increased the specific surface area from 283.2 to 517.5 m2/g. The inhomogeneity in the modified AC absorbent surface is less compared to AC, and it also has a more regular surface in terms of particle size uniformity. The ability of prepared adsorbents to remove phenol in aqueous medium was evaluated by examining the effects of parameters such as adsorbent amount, pH, solution concentration, contact time, temperature effect. Based on the results, it was found that AC/Cu shows the highest adsorption rate after coming in contact with phenol solution with a concentration of 100 ppm for one hour at an optimal pH of 8. The adsorption of phenol by AC/Cu is consistent with the pseudo-second-order kinetic model. The absorption of phenol by the modified AC depends on the temperature and is an endothermic process. The increase in the amount of phenol removal with increasing temperature is more in AC/Cu. The study of the adsorbent saturation in the column system showed that AC/Cu is able to absorb more than 95% of the phenol solution with a concentration of 100 ppm up to a volume of 2700 mL. The findings of this study provide valuable insights into the field and pave the way for further research in the future.

In recent years, attention to novel papermaking processes has increased significantly. The SEW fractionation process is one of the novel processes for producing a wide range of high value-added products such as pulp, paper, lignosulfonates, and biofuels in a biorefinery system. This study aimed to investigate the possibility of producing pulp and paper from Eldar pine (Pinus eldarica) using SEW fractionation and comparing it with the Kraft process followed by elemental chlorine free (ECF) bleaching. The results showed that the tensile, burst, and tear indexes are lower for SEW handsheets than for Kraft handsheets. The brightness before bleaching of SEW handsheets is higher than that of Kraft handsheets. The apparent density is higher for the SEW handsheets than the Kraft. Since there are some limitations in the use of SEW pulps such as high apparent density and lower strength properties than the Kraft pulps, however, these factors do not create industrial constraints for the use of these pulps. Low energy consumption of SEW pulps in the beating and high brightness before bleaching are among the obvious advantages of the SEW process. Therefore, it seems that in cellulose conversion industries, such as the production of nanocellulose, the use of SEW pulps has many advantages in terms of energy consumption, and the high brightness before bleaching eliminates long bleaching sequences in pulp mills. [ABSTRACT FROM AUTHOR]

Defibrillating cellulose through various grinding steps and incorporating it into hydrogels introduces unique properties that warrant thorough exploration. This study investigates cellulose defibrillation at different steps (15–120) using an ultra-fine friction grinder, blended with high-molecular-weight polyvinyl alcohol (PVA), and crosslinked via freeze–thawing. A critical discovery is the influence of defibrillation on the hydrogel structure, as evidenced by reduced crystallinity, thermal degradation, and the enhanced swelling of PVA chains. Despite an increased elastic modulus of up to 120 steps, the synthesized material maintains remarkable strength under hydrated conditions, holding significant promise in biomaterial applications. [ABSTRACT FROM AUTHOR]

ABSTRACT: Two trials were performed in order to evaluate the effects of dietary Kraft lignin inclusion on broiler performance, ileal nutrient digestibility, blood lipid profile, intestinal morphometry, and lipid oxidation of meat. Trial 1 was conducted in order to evaluate performance and ileal digestibility for the period of 1 to 21 d of age, randomly distributing 490 day-old broiler chicks across 5 dietary treatments with 14 replicates containing 7 birds each in metabolic cages, while trial 2 was executed in order to evaluate performance, blood parameters, intestinal morphometry, carcass yield and abdominal fat, and lipid oxidation for the period of 1 to 42 d of age, randomly distributing 900 day-old broiler chicks across 5 dietary treatments with 15 replicates of 12 birds each in floor pens, being each bird in trial 2 challenged with coccidiosis vaccine at 10 d of age. The treatments used in both trials were: positive control (PC): basal diet + antimicrobial; negative control (NC): Basal diet; NC1: NC + 1% lignin; NC2: NC + 2% lignin; NC3: NC + 3% lignin. For trial 1, it was observed that birds fed diets containing 1% lignin had a significant positive effect for BW, feed intake (FI), average daily weight gain (BWG) and feed conversion rate (FCR), similar to the PC, but also showing better EE, CP and AAs ileal digestibility percentages when compared to other treatments. For trial 2, it was observed that during the period of 21 to 35 d, the inclusion of lignin in the diet provided better results in animal performance, similar to the PC group, but at 42 d, animals fed with dietary lignin showed results lower than animals fed the PC diet (P < 0.05). Animals fed with increasing lignin concentrations showed decreasing levels of HDL (P < 0.05). As of intestinal morphometry, animals fed with 1% and 3% lignin showed longer intestinal length (P < 0.05). At 14 d of age, it was observed that animals fed with lignin showed oxidation levels similar to the control treatments. The inclusion of up to 1% lignin in the diet provides beneficial effects on productive performance and nutrient digestibility, while the inclusion of 2% lignin provided lower cholesterol levels, lower villus/crypt ratio, and better internal organ development, therefore, it can be considered an alternative to performance-enhancing antimicrobials in broiler chicken diets.

Plant fiber classified as environmentally friendly material is a promising renewable engineering material rich in lignocellulose that can be employed in the pulp and paper industry as a substitution to wood which has been entailing negative environmental impacts due to acute deforestation. This paper assesses the feasibility of manufacturing biodegradable, writable and eco-friendly papers from waste coconut husk which is a low-cost and locally available biomass. The biomass was used along with wastepaper in different ratios. Papers of 60 gm−2 were produced with and without binder. Starch was added as binder to strengthen the paper and increase its resistance to bursting and abrasion. The properties of the paper were assessed through physical and mechanical tests. The mean thickness of the unreinforced and starch reinforced papers were 0.267 ± 0.012 mm and 0.282 ± 0.016 mm respectively. The reinforced 100% coconut husk paper specimens demonstrated greatest tensile and burst index of 19.25 Nmg−1 and 2.266 kPam2g−1 respectively requiring the highest number of 125 turns to get abraded. Unreinforced 60% coconut fibers showed lowest absorbency rate implying that it is 35 times more absorbent than 60 g/m2 normal paper. The paper specimens having highest mean recovery angle suitable for writing materials were the reinforced 60% Cocos Nucifera and 40% wastepaper (77.6°).

The biomass deconstructed by kraft process and the lignin dissolved in the black liquor are burned to generate energy in a pulp mill. This study used the black liquor from coffee parchment cooking, a residue from the coffee industry, to isolate kraft technical lignin. The parchment was subjected to the kraft pulping process to obtain pulps of kappa number 60 and 25, and the resulting black liquors were used for lignin extraction. Chemical characterization, elemental analysis and heating value of liquors and lignins were performed, as well as FTIR and Py-CG-MS analysis of lignins. The cooking provided liquors with similar characteristics, with lignin content of 31.67 and 32.63% for kappa 60 and 25 liquors, respectively. The extractions resulted in high purity lignin (92.35% for K#60 lignin and 93.96% for K#25 lignin). The higher heating values were 23.8 and 25.4 MJ/kg for K#25 and K#60 lignins, respectively. FTIR analysis showed characteristic peaks of lignin. Through Py-GC-MS, it was possible to observe the slight predominance of guaiacyl-type lignin, which can be an advantage depending on the application. It is possible to extract lignin from the black liquor obtained from the coffee parchment pulping to generate products with high-added value. [ABSTRACT FROM AUTHOR]

Defibrillating cellulose through various grinding steps and incorporating it into hydrogels introduces unique properties that warrant thorough exploration. This study investigates cellulose defibrillation at different steps (15–120) using an ultra-fine friction grinder, blended with high-molecular-weight polyvinyl alcohol (PVA), and crosslinked via freeze–thawing. A critical discovery is the influence of defibrillation on the hydrogel structure, as evidenced by reduced crystallinity, thermal degradation, and the enhanced swelling of PVA chains. Despite an increased elastic modulus of up to 120 steps, the synthesized material maintains remarkable strength under hydrated conditions, holding significant promise in biomaterial applications.

Mass transport of liberated lignin fragments from pits and fiber walls into black liquor is considered a determining step in the delignification process. However, our current understanding of the diffusion of lignin through cellulose and the influential parameter on this process is very limited. A comprehensive and detailed study of lignin mass transport through cellulosic materials is, therefore, of great importance. In this study, diffusion cell methodology is implemented to systematically investigate the transport of fractionated kraft lignin molecules through model cellulose membranes. Pulping is a complex process and lignin is very heterogenous material therefore to perform a more detailed study on lignin diffusion, we included an additional solvent fractionation step. One of the benefits of this method is that the setup can be adjusted to various experimental conditions allowing the complex chemical reactions occurring during pulping, which would affect the mass transfer of lignin, to be avoided. Here, the effects of the alkalinity of the aqueous solution and molecular weight of the kraft lignin molecules on their diffusion were investigated. Additionally, NMR spectroscopy, size exclusion chromatography, and UV/Vis spectroscopy were used to characterize the starting material and the molecules that passed through the membrane. Lignin molecules detected in the acceptor chamber of the diffusion cells had lower molecular weights, indicating a size fractionation between the donor and acceptor chamber. UV/Vis showed higher concentrations of ionized conjugated kraft lignin molecules in the acceptor chamber, which is a sign of chemical fractionation. This study suggests that the diffusion of lignin through small cellulose pores can be enhanced by decreasing the average molecular weight of the diffusing kraft lignin molecules and increasing alkalinity. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd 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.)

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal 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.)

Abstract This study aims to optimize strong acid hydrolysis-based production of cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) from pre-extracted and fully bleached kraft pulp of loblolly pinewood, the most abundant and commercially significant softwood species in southeastern United States. The effect of four parameters, including acid concentration, temperature, duration and pulp particle size, on the yield and properties of CNCs was investigated using the central composite design (CCD) of response surface methodology (RSM) for process optimization. While CNC yield was significantly affected by acid concentration and hydrolysis temperature and was adequately explained by an empirical model, none of the characteristic properties of CNCs, including crystallinity index, surface charge and particle size, displayed any strong correlation to the process parameters within the experimental ranges tested. At different hydrolysis severities, we not only analyzed the waste streams to determine the extent of holocellulose degradation, but also evaluated the properties of leftover partially hydrolyzed pulp, called cellulosic solid residues (CSR), to gauge its potential for CNF production via mechanical fibrillation. Conditions that maximized CNC yields (60% w/w) were 60% acid concentration, 58 °C, 60 min and 40 mesh particle size. Twenty percent (w/w) of the pulp was degraded under these conditions. On the other hand, conditions that maximized CSR yields (60% w/w) were 54% acid, 45 °C, 90 min and 20 mesh particle size, which also produced 15% CNCs, caused minimal pulp degradation (

Black liquor (BL) dewatering by multi‐effect evaporation in the kraft papermaking process is highly energy‐intensive. It was previously shown that graphene oxide (GO) nanofiltration membranes can remove lignin, other organics, and inorganic salts from BL while exhibiting stability in caustic BL conditions. Here, we design and simulate several candidate dewatering processes and evaluate their technoeconomic characteristics. All processes concentrate BL from 15 to 30 wt% solutes while producing aqueous permeate. Two process options were analyzed—option A including "last‐mile" permeate treatment to reduce solutes to 0.2 wt%, and option B excluding this treatment and producing a 3–4 wt% solutes stream. These processes were simulated in custom‐built ASPEN Plus flowsheets interfaced with Microsoft Excel and MATLAB. All processes deliver large (>40%) energy savings. Detailed technoeconomic analysis showed that option A processes are profitable in mills equipped with condensing turbines, but unprofitable with only purchased fuel savings. Option B processes are profitable in both situations, but require the caustic permeate to be utilized in other kraft process units. They are also profitable with electricity generation when operated at smaller scales matching the requirements of other process units. Monte‐Carlo sensitivity analysis shows that Option A can yield median 20‐year NPVs up to ~$10MM and Option B up to ~$25MM. Overall, GO membrane‐based BL dewatering is economically promising, assuming successful slipstream piloting and scale‐up campaigns. It would have immediate sustainability benefits from large energy savings, and broader implications for biorefinery processes due to the ability to fractionate biomass feedstock components under harsh conditions. [ABSTRACT FROM AUTHOR]

Abstract Indigenous plants are widely abundant in Mauritius and if made proper use of, these renewable plants can contribute largely to the local economic sector. This paper assesses the suitability of producing eco-friendly and biodegradable papers using low-cost raw materials by means of fibre from Pandanus utilis’ leaves commonly known as ‘Vacoas’. The leaves were used along with Arundo donax or wastepaper to manufacture composite paper samples in the ratios of 20:80, 40:60, 60:40, 80:20 and 100:0. Chemical pulping was done through Kraft process for a period of 1.5 h at a concentration of 14 wt% NaOH and 4 wt% Na2S at 90 ± 2.5 °C. The mean thickness of the papers was determined to be 0.261 ± 0.027 mm. It was found that the 100% Vacoas fibres had the highest absorbency rate of 1.8 ± 0.5 s followed by the composite A. donax and Vacoas fibre (1.8 ± 0.3 s). The most abrasion resistant paper which also demonstrated the highest burst index of 0.63 kPa m2 g− 1 and tensile index 11.8 N m g− 1 was observed to be that of 100:0 Vacoas fibre paper requiring 35 turns to get abraded followed by the P. utilis and A. donax mix where the 80:20 fibre ratio revealed a high bursting index of 0.45 kPa m2 g− 1 requiring 25 turns to get abraded while 40% P. utilis and 60% A. donax had a high tensile strength of 11.9 N m g− 1. Vacoas to wastepaper mix ratios of 20:80 and 40:60 were found to have the highest mean recovery angles of 61.3 and 59.6°, respectively.

This study aims to optimize strong acid hydrolysis-based production of cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) from pre-extracted and fully bleached kraft pulp of loblolly pinewood, the most abundant and commercially significant softwood species in southeastern United States. The effect of four parameters, including acid concentration, temperature, duration and pulp particle size, on the yield and properties of CNCs was investigated using the central composite design (CCD) of response surface methodology (RSM) for process optimization. While CNC yield was significantly affected by acid concentration and hydrolysis temperature and was adequately explained by an empirical model, none of the characteristic properties of CNCs, including crystallinity index, surface charge and particle size, displayed any strong correlation to the process parameters within the experimental ranges tested. At different hydrolysis severities, we not only analyzed the waste streams to determine the extent of holocellulose degradation, but also evaluated the properties of leftover partially hydrolyzed pulp, called cellulosic solid residues (CSR), to gauge its potential for CNF production via mechanical fibrillation. Conditions that maximized CNC yields (60% w/w) were 60% acid concentration, 58 °C, 60 min and 40 mesh particle size. Twenty percent (w/w) of the pulp was degraded under these conditions. On the other hand, conditions that maximized CSR yields (60% w/w) were 54% acid, 45 °C, 90 min and 20 mesh particle size, which also produced 15% CNCs, caused minimal pulp degradation (< 5%) and imparted sufficient surface charge such that CSR was easily microfluidized into CNFs. Therefore, the strong acid hydrolysis process could be tuned to maximize the production of cellulose nanocrystals and nanofibers and obtain two products with different properties and applications through the process optimization. [ABSTRACT FROM AUTHOR]

A phenomenological model of cellulose production processes presents limitations due to the presence of species and chemical reactions of complex computational representation. Modeling based on machine learning techniques is an alternative to overcome this drawback. This paper addresses the Gaussian process regressor (Kriging) method to model the oxygen delignification process in one of the largest pulp production plants of the world. Different correlation models were used to evaluate this method; furthermore, an optimization routine, based on the constrained optimization by linear approximation method, was coupled to model to minimize the objective function, which is based on the input cost. Results have shown the good performance of using a combined Kriging method with optimization routines in the non-linear industrial processes to obtain a representative model capable of providing optimized operating scenarios. A reduction of 36.5% in consumption of NaOH was obtained, while required restrictions are obeyed. [ABSTRACT FROM AUTHOR]

In the last few years, a serious effort has been initiated to develop standard methods for lignin characterization at the national and international levels. Thus, several Canadian and ISO standards were recently developed. The current results were generated in an effort to assist the ISO/TC6 Committee come up with a reliable standard method for the measurement of the dry solids content of lignins. In particular, this work investigated the drying of lignin using three different drying methods: conduction oven drying (105 °C), vacuum oven drying at (60 °C), and freeze drying. Ten different lignins were used in this study including wet and air-dried softwood and hardwood kraft lignins in the acid and base forms from the industrial LignoForce™ process and hydrolysis lignin from the TMP-Bio™ process. The results showed that 7 h, 48 h and 24 h were sufficient to reach a constant solids content in the case of all lignins when oven drying, vacuum oven drying under negative pressure (150 mbar), and freeze drying (25 mT) were used, respectively. Kraft lignins in the base form showed higher sensitivity to degradation compared to lignins in the acid form. The total hydroxyl group content of air-dried and wet hardwood lignins in the base form decreased by more than 50 % after vacuum oven-drying for 71.5 h or oven-drying for 16 h compared to freeze-drying for 68 h. The decrease in the total hydroxyl groups was more pronounced (70 %) when the wet softwood lignin in the base form was dried in the oven compared to freeze drying for 68 h. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal 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.)

Abstract: Technical lignins are bulk feedstocks. They are generated as byproducts from pulping or cellulosic ethanol production. As lignin undergoes significant structural changes as a result of chemical and physical treatments, all technical lignins are unique in terms of chemical structure, molecular weight, polydispersity, and impurity profile. Kraft lignin is potentially the largest source of technical lignin as new isolation technologies have been implemented on an industrial scale in recent years. Lignosulfonate has been an integral product in sulfite pulping biorefineries. It has a well established market in the construction industry. Organosolv‐like lignin production is increasing as cellulosic ethanol has been promoted as a substitute for fossil fuel. It may have unique applications because it has low molecule weight and is free from sulfur. Technical applications of lignin are expected to expand as its characteristics are improved with fractionation or chemical modification. The application of technical lignin has been focusing on developing products equivalent to those made by petroleum chemicals. Recent developments in technical lignin supply should increase its market share as an additive in polyurethanes and as a substitute for phenol‐formaldehyde adhesives. Quality improvement of technical lignin may also encourage the study of lignin as an alternative feedstock for carbon fiber. Moreover, technical lignin depolymerization has been extensively explored to provide renewable aromatic chemicals. Starting from controlled pyrolysis and thermal liquefaction as the baseline technologies, many different chemical depolymerizations have been invented with a wide range of underlying chemical principles. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the delignification of Eucalyptus camaldulensis fibers by the kraft chemical process using sodium hydroxide and sodium sulfide as fillers. To optimize the levels of factors influencing pulp yield and pulp content, a response surface approach with a central composite plane was used. Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis were used to characterize the structure and thermal properties of cellulose fiber. Then, a dynamometer, a dechirometer, and an eclatometer adamel were used to evaluate the physico-mechanical properties (breaking length, tear resistance, and resistance to burst) of the paste. The results show that FTIR spectroscopy confirmed the structure of the cellulose fiber; the crystallinity index is 76.35%, the maximum degradation temperature is 368 °C and the kinetic energy of activation (75.45 kJ.mol -1) according to thermogravimetric studies. Subsequently, for the predicted optimal pulping conditions, the concentration of NaOH was 18.8% and 13.40% Na2S at 105 °C for 45 min. Finally, the results obtained for the evaluation of the papermaking properties of fibers during refining showed that the breaking length is 34% (2975 m–1958 m) with a sulfide concentration of 0%–30%, respectively, and that when the refining intensity is increased to 45°SR, the rupture length (5997-4088 m) decreases by approximately 31% under the same conditions. Then, the tear strength is 37.5% (53-33.1), the sulfide concentration is 0%–30%, and the refining intensity is 20°SR; the increase in the latter leads to a reduction in the tear index of approximately 19% (50-40.6) under the same conditions. Finally, the bursting index is 38.5% (18.4-11.3) at identical sulphide concentration and refining intensity, but the increase in the latter leads to a slight decrease in the burst index (37.7-23.6) which is about 37.40%. The results suggest that the valorization of Eucalyptus fibers for the production of well-delignified, high-yield, and resistant pulp is a promising approach. This research qualifies eucalyptus fiber as a potential reinforcement in composite materials. • The kraft chemical process produces better extraction and quality of the cellulose. • FTIR and X-ray analysis confirmed that the fibers are rich in cellulose (76.35%). • TGA analysis indicated that the EC fibers are thermally stable until 368 °C. • The refining intensity improves the physico-mechanical properties of the cellulose fiber. • This research qualifies EC fiber as a potential reinforcement in composite materials. [ABSTRACT FROM AUTHOR]

In this study pulp and hand sheets paper characteristics of Salix nigra wood kraft and soda pulp and paper were investigated. Average density of dry and bulk density wood were determined 0.35 and 150 kg/m3 and average fiber dimension consist of fiber length, fiber diameter were measured, 1100 and 30 µm, respectively. The chemical composition were determined as cellulose 42%, lignin 28% and extractive 4%. In order to coocking and pulping, Kraft (Sulfate) and soda process were used. For comparison of fiber dimensions, physical properties and chemical composition of the mean and standard deviation, yields of pulp in the form of a factorial randomized complete block design test, the strength properties of handsheets table ANOVA and for group means of the Duncan were used. All paper strengths of two hour cooking show better results than one hour cooking times, and all paper strengths of 22% alkaline show better result than 18%, also all paper strengths of 100% mixture show better result than 25% mixture (100% mixture only contain kraft pulpof salix nigra). The results of hand sheet strength indicated that Kraft pulp of salix nigra wood will provide a suitable to mix with short fiber hard wood pulp.