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CaCl2 solution and Ca(OH)2 slurry, both prepared from marble waste (MARWAS), were carbonated with CO2 gas in the presence of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), Teepol-610s, Triton X-100, and Tween-80 as the surface modifiers in a semi-batch foam-bed reactor (FBR) to synthesize ultrafine or submicron precipitated calcium carbonate (PCC) particles with enhanced hydrophobicity. Nano/ultrafine PCC particles with and without surfactant were also synthesized in a semi-batch stirrer reactor (SR) using CaCl2 solutions made from MARWAS and NH4HCO3 as the carbonating agent by single or simultaneous application of ultrasonication (US) and surfactant, respectively. The products were characterized by SEM, TEM, XRD, FTIR, and drop-shape analyzer. In the presence of SDS in the FBR, distinct and smaller hydrophobic (water contact angle of 103.3°) vaterite particles (426 nm) could be produced using CaCl2 solution than those with the Ca(OH)2 slurry. However, in the SR, methanol was more effective than the aqueous solvent in synthesizing needle-like aragonite nanoparticles (215.6 nm with L/D = 8.55) from CaCl2 solution without any use of US or surfactant. Handmade papers were manufactured using ground MARWAS powder, modified- and unmodified-PCC. The physical, mechanical, and optical properties of these filler-loaded papers were determined. The use of surface-modified and unmodified PCC was superior to the commercial PCC in increasing filler retention, burst strength, tear strength, brightness, and opacity of the paper handsheets. Even the direct use of MARWAS powder was more effective than ground calcium carbonate in enhancing the optical properties with a slight decrease in the mechanical strength. Utilization of marble waste into papermaking [ABSTRACT FROM AUTHOR]

The paper industry is constantly seeking innovative ways to improve paper quality, increase process efficiency and reduce environmental impact. The unique properties of cationic modification of hemicellulose provide an opportunity to achieve these goals. Herein, eucalyptus hemicellulose was modified with quaternary ammonium groups to yield cationic hemicellulose (CH), which was used to elaborate structural and functional interactions between CH and cellulose nanofibrils (CNFs). These interactions were quantitatively monitored by a quartz crystal microbalance with dissipation (QCM-D). We empirically studied bonding motifs between CNFs and hemicellulose by forming films. The degree of substitution (DS) of CH was made between 0.095 and 0.254 by varying the molar ratio of the reaction, leading to a gamut of positive charges in hemicellulose. The adsorption of CH to a CNF surface was related to electrostatic interactions. The high DS of CH had higher adsorption rate and larger adsorption capacity within the CNF-surface, while CH as a reinforcing agent significantly increased the tensile strength of the film by hydrogen bonding, which was 71% higher than that of unmodified hemicellulose. The strong binding between CH and nanocellulose may highlight a platform to develop paper additives and nanocellulose composites for high-value applications. [ABSTRACT FROM AUTHOR]

Process industry suffers from production management in terms of efficiency promotion and waste reduction in large scale manufacturing due to poor organization of the intricate relational databases. In order to enhance the suitability of intelligent manufacturing systems in process industry, this study proposed an innovative top-down structure Knowledge Graph (KG) for process fault diagnosis, and papermaking was taken as a case study. The KG consists of a normalized seven-step-built ontology, which extracted instances of papermaking knowledge via Protégé software. The exported OWL file was imported into Neo4j software for visualization of the KG. The application in papermaking drying process for fault diagnosis shows that it can depict the material and energy flows throughout the process with a clearer relationship visualization than traditional measures. They also enable rationale search for faults and identification of their potential causes. The built KG efficiently manages the vast knowledge of the process, stores unstructured data, and promotes the intelligent development of process with high reusability and dynamicity that can rapidly import new production knowledge as well as flexibly self-updating. [ABSTRACT FROM AUTHOR]

During cocoa processing, a considerable residue of biomass with high economic potential is generated. The purpose of this research was to evaluate whether cocoa husk residue after cocoa harvesting has the potential to be used as a fibre source in papermaking applications for packaging. Cocoa husk was collected, and pulp was produced chemically from the obtained biomass. Lignocellulosic components, ash and extractive content were established using standard or well-established methods. The results were in line with previous literature studies and demonstrated that agricultural residual biomass from cocoa husk contains 34.6% cellulose which is similar to wood fibre, but with higher lignin (30.7%) and ash content (9.0%). Chemical pulping and screening delivered a very low fibre yield of 19.6% which was further reduced to 11% after bleaching. Morphological properties of the obtained pulp were also measured. The obtained fibres after bleaching were very short (0.348 mm) and coarse (43.4 µm) when compared to softwood fibres. Laboratory handsheets with different blends of cocoa husk and commercial softwood fibres were prepared. The impact on handsheet properties were studied. The unbleached and bleached cocoa husk pulps were not suitable for papermaking as individual fibre sources, due to poor bonding characteristics and very slow drainage, respectively. When unbleached cocoa husk pulp was blended with softwood pulp, the strength properties of the sheets were negatively impacted. As cocoa husk fibre content was increased to 30% and 50%, tensile decreased by 10–34%, tear by 13–37%, burst by 22–39% and bending stiffness by 13–21%, respectively, making such addition undesirable for lightweight paper packaging applications. The addition of 30% bleached cocoa husk fibre to softwood, however, showed an improvement of 39% in tensile strength and 11% in burst, while tearing resistance and bending stiffness were compromised by 16% and 15%, respectively. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the versatility of thermophilic esterase for treating raw papermaking whitewater with organic solvents at high temperatures. Thermophilic esterase from a metagenomic library was immobilized on a chitosan/macroporous resin composite carrier using a covalent crosslinking approach in conjunction with deep eutectic solvent (DES). The stability and tolerance of the immobilized thermophilic esterase were greatly enhanced by DES. Immobilized thermophilic esterase resulted in significant 85.35% and 88.02% reductions in the average particle size and pitch deposit contents, respectively. Furthermore, clear decreases in turbidity, chemical oxygen demand and biochemical oxygen demand were found, indicating an optimal treatment outcome for all the commercial enzymes that were examined. The superior efficacy of thermophilic esterase in the treatment of raw whitewater was found to be due to the effective removal of colloidal substances such as polyvinyl acetate. Therefore, this research had significant potential for the enzymatic treatment of raw whitewater. [ABSTRACT FROM AUTHOR]

Developing an environmentally friendly and more efficient pulping process is necessary to cope with the pollution issues created by the current pulp and paper mills. Although Organosolv pulping is considered environmentally friendly compared to kraft or soda pulping, the higher cost hindered the commercialization of the Organosolv process to pulp different raw materials. Therefore, this research aimed to explore the papermaking potential of three raw materials i.e., spruce, beech, and miscanthus, using Acetosolv pulping. This research also includes the determination of properties of the fibers influenced by refining and application potential that could arise for the fibers in terms of strength, barrier, and optical properties. Paper sheets showed excellent air barriers, which justifies their applications in the packaging sector. It was concluded that if the tensile index is the selection criteria, then even miscanthus (a nonwood material) Acetosolv pulp can replace the spruce softwood kraft pulp. Also, transparency and contact angle were found to be maximum for spruce which can facilitate its application as a substrate in green electronics. [ABSTRACT FROM AUTHOR]

Improving paper characteristics through natural and cost-effective fillers is a massive issue in the paper industry. In the process of manufacturing paper, inorganic and organic fillers are utilized. Organic fillers are only appropriate for specific applications, and their expensive cost has limited their use. Here, various concentrations of sugarcane press mud (SPM) waste were applied to obtain pure calcium oxide nanoparticles (CaONPs) after the calcination to use as a potential filler in the papermaking by mixing the CaONPs at various ratios (5, 10, 15, and 20%), and paper properties have been investigated. Transmission electron microscopy (TEM), selected area electron diffraction (SAED), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) were utilized to characterize the CaONPs produced. The finding reveals that the influence of nano CaO fillers filled at different ratios (5, 10, 15, and 20%) on tensile, tear index, porosity, and smoothness was slowly decreased when increasing the content of nano filler to 35.9, 55.0, 565.7, and 260.3 at (0%) decrease to 30.7, 42.4, 381.6, and 188.4 at (20%), respectively. Also, opacity and brightness were increased from 93.0 and 71.7 at (0%) to 99.0 and 72.3 at (20%), respectively. The previous results revealed that the CaONPs at (20%) represent the optimal owing to the small particle size of CaONPs is satisfactory for provoking the prosperities of paper. [ABSTRACT FROM AUTHOR]

In this contribution, we report on the TEMPO-mediated oxidation of pulp fibers used in the general context of papermaking and for the future design of tailor-made paper in advanced applications. We focus in our studies on properties of TEMPO-oxidized pulp fibers to explain the characteristics of the paper made thereof. 13C solid-state NMR analysis reveals that in particular amorphous regions of the fibers are being chemically oxidized, while at the same time the crystalline regions of the fibers are not significantly affected. Investigation of the fiber morphology before and after oxidation shows that the fiber length is not changed, yet the fibers do exhibit an increase in width if in contact with water, which is attributed to an increase in fiber swelling. In addition, fibrillation decreases due to the oxidative removal of loosely bound fines and fibrils, rendering the surface of the resulting oxidized fibers much smoother in comparison to the original fibers. Finally, we observe that both, dry and wet tensile strengths are also higher for paper made of oxidized fibers, most likely due to cross linkable aldehyde groups formed during oxidation (i.e. hemiacetal bond formation in the sheet during thermal drying). Our results of the oxidation of paper fibers thus offer a systematic study helpful for the design of tailor-made paper useful in several applications where a fiber-modification with fiber-immobilized functional motifs is crucial, such as for example in paper-based microfluidic sensors (µPADs) or lab-on a chip-devices. [ABSTRACT FROM AUTHOR]

Burning corncob for energy requirements caused a huge waste of biomass resources and serious environment pollution. Herein, this study provided a high-value utilization strategy for corncob. Corncob was first pretreated by hydrothermal process. The collected hydrolysates were converted into furfural by a recyclable solid acid with a yield of 52.35%. The pretreated solid was disintegrated into fibers by disc grinding. When corncob fiber addition is below 15%, the ring crush index, tear index, and tensile strength index of the prepared handsheets increased by 1.43 N·m/g, 0.43 mN·m2/g, and 4.66 N·m/g, respectively, compared with that using pure softwood fibers. Besides, corncob fibers were hydrophilically modified with aminosulfonic acid. Water retention value of paper with the modified fiber addition increased by 48.35%. Therefore, this study provided a method of corncob utilization toward two purposes: furfural production and papermaking. [ABSTRACT FROM AUTHOR]

The influence of pulp carryover on the efficiency of the xylanase (X) treatment of industrial unbleached and oxygen-delignified eucalypt kraft pulps (A1 and A2 pulps, with kappa number (KN) values of 16 and 10, respectively), collected at the same pulp mill, was studied regarding the consumption of bleaching chemicals and pulp bleachability. Another non-oxygen-delignified eucalyptus kraft pulp of KN 13 was received after the extended cooking from a different pulp mill (pulp B). The assays were performed with both lab-washed (carryover-free) and unwashed (carryover-rich) pulps. Both lab-washed and unwashed pulps with carryover were subjected to X treatment, the former being demonstrating considerably higher ClO2 savings than the pulps containing carryover. The savings of bleaching reagents were higher when the X stage was applied to the A1 pulp than to the A2 pulp. This advantage of A1 pulp, however, was not confirmed when using unwashed pulps. In contrast, the gains obtained from the X treatment of unwashed pulp A2 were practically as high as those observed for the lab-washed A2 pulp. Furthermore, a similar effect in X stage was recorded for unwashed pulps having close KN: oxygen-delignified A2 pulp and non-oxygen-delignified B pulp. The results suggest that pulp carryover and initial pH were the key factors relating to the effectiveness of X treatment. The application of X treatment to the A2 unwashed pulp (after the oxygen stage) not only saved 20% of the ClO2 and 10% of the sodium hydroxide, but also improved the brightness stability of the bleached pulp without affecting its papermaking properties. Key points: • Xylanase treatment boosts kraft pulp bleaching • Pulp carryover hinders the xylanase treatment • Nearly 20% of ClO2 and 10% NaOH savings can be reached using xylanase [ABSTRACT FROM AUTHOR]

Congestion is a well-known economic phenomenon in which excessive inputs lead to a decrease in the maximum possible outputs. This study analyzes the relationship between congestion and overinvestment using a data envelopment analysis framework to reveal that some congestion can be eliminated by increasing inputs. The proposed approach classifies congestion into two categories, relative and absolute congestion, depending on the possibility of eliminating congestion by increasing inputs. Corresponding methods for identifying and measuring congestion are proposed and employed for empirical analyses examining China's papermaking and paper products industry. We find that most congestion in 2013–2016 is in the relative congestion and could be eliminated by increasing inputs. The primary causes of congestion are identified based on our analysis and corresponding policy suggestions are proposed for eliminating congestion. [ABSTRACT FROM AUTHOR]

Oyster Farming is one of important fisheries and aquaculture industries in Taiwan. Each year, approximately 4000–5000 tons of discarded bamboo scaffolding (BS) used in oyster farming, are generated, so the treatment and utilization of BS should be taken seriously. This study evaluates the suitability of BS for pulp and papermaking by assessing the chemical compositions, microstructural, and fiber morphology. The pulping properties is investigated by soda pulping. The chemical composition of BS shows the potential for application in pulping. The BS microstructure shows that can enhance pulping reactions, while the fiber morphology indicates the possibility of producing high-strength paper. Through the pulping experiment, it demonstrated that BS is suitable for pulping with lower NaOH dosage and longer digestion time. The condition at 170 °C with 14% NaOH dosage for 90 min digestion has the highest yield. After refining the highest pulping yield BS pulp, it can improve the handsheet strength and bulk of the OCC-BS mixed pulp, which can achieve the strength property required for industrial paper. In summary, BS exhibits the potential for pulping application and produces a better paper strength than OCC pulp, exhibiting the feasibility of enhancing the circular utilization value of BS in Taiwan. [ABSTRACT FROM AUTHOR]

Lignin has a UV-blocking ability because it contains phenolic and ketone functional groups. However, the lignin produced in the paper industry undergoes extreme polycondensation, resulting in an extremely dark color, which impedes its value-added application in the field of UV-blocking cosmetics. In this study, maleic acid (MA) was used as a green and recyclable reagent to pretreat an agricultural waste lignocellulosic biomass, Kenaf stalk. Lignin underwent a carboxyl esterification reaction with MA to produce light-colored dissolved lignin (DL), which was further prepared into lignin nanospheres and used in lignin-based sunscreens. The results showed that when adding 5 wt% DL-lignin nanospheres (DL-LNPs) to a sunscreen with an actual measured sun protection factor (SPF) of 7.05, the SPF of the lignin-based sunscreen increased to 63.82 far exceeding the commercially available SPF 50 sunscreens. The prepared lignin-based sunscreen had good biocompatibility when applied to human skin and did not stain the skin. The remaining neutral solid after pretreatment was made into Kenaf fibers by PFI milling for papermaking. The ring crush strength index of the paper increased from 2.81 N m/g to 3.14 N m/g when 15 wt% Kenaf fibers was added to the softwood pulp. When the additions Kenaf fibers was 5 wt%, the tensile index and tearing index of the paper increased from 8.57 N m/g and 4.68 mN m2/g to 9.22 N m/g and 5.48 mN m2/g, respectively. Therefore, this study provides a new way for the value-added utilization of Kenaf stalk lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

A vast range of extraction processes, chemistries, and wet processing methods have been explored to improve the opto-mechanical properties of nanocellulosic materials. However, the stresses that arise during drying have been scarcely examined, in particular for their impact on performance. As with papermaking, drying is a critical step that significantly impacts the properties of nanocellulosic materials. The nano- and micro-scaled dimensions of nanocelluloses provide opportunities beyond those achievable in paper science, as the associated drying stresses are several orders of magnitude higher than those at the macroscale. Drying may be utilized towards the generation of assemblies with functional structures and enhanced properties. Herein, we highlight recent examples where such drying stresses are tethered to the structure of nanocellulosic materials. Using cellulose nanocrystals (CNCs), we investigate how the stresses that develop upon consolidation, and that remain thereafter (i.e., residual stresses), correlate with the mechanical performance of the obtained materials. We extend this analysis through results that highlight the impact of the "history" of drying of CNCs on the dynamics of the residual stresses. We also briefly discuss how inhomogeneous concentration gradients in drying suspensions may play an important role in the formation of superstructures across a range of nanocellulosic materials. Overall, by highlighting the importance of drying, we expect a more closely scrutinized science of drying to improve the properties of structures based on nanocellulose. [ABSTRACT FROM AUTHOR]

The paper and pulp industry is one of the fastest-growing sectors and has exhibited fast growth in recent years. This is linked to the increased environmental pressure due to the use of virgin fibre from wood as raw material followed by its chemical mediated processing. This prompted the development of technologies that can replace conventional industrial processing. The tree based fibres can be replaced with secondary fibres and enzyme mediated processing can serve as a sustainable alternative to conventional procedures. Cellulase, amylase, pectinase, protease, and xylanase enzymes, as well as a consortium of these enzymes, are commercially available that can efficiently be used for bioretting, biopulping, biobleaching, biodeinking, and biorefining. The eco-friendly bio-based processing has resulted in reduced environmental load as evidenced by the reduction in the BOD and COD values to permissible levels. Enzymes offer significant potential in the production of paper owing to their high efficacy, bio renewability, mildness, non-polluting nature, high selectivity, low cost, and enhanced paper quality. This review intends to draw attention to the effective usage of enzymes for processing in the paper and pulp-based sectors. Biobased processing, alone or in combination with chemicals can prove to be an environment-friendly approach promoting environmental sustainability. [ABSTRACT FROM AUTHOR]

As the carrier of enterprise water resources management disclosure, water information disclosure is a means of expression of enterprises' environmental responsibility. First, a corporate water information disclosure quality evaluation index system and evaluation method are established, and with the help of the projection tracing method of accelerated genetic algorithm, 27 paper companies in China are selected as a sample and the disclosure quality level is analyzed empirically. Then, the analysis is carried out in terms of three changes in vertical trends, horizontal trends and changes in laws, regulations and policies, and the results show that Chinese paper and paper product enterprises have low quality of water information disclosure, weak disclosure content and low voluntary disclosure. Finally, feasible suggestions are made based on the evaluation of disclosure issues. [ABSTRACT FROM AUTHOR]

Industrial progress in papermaking in the early nineteenth century led to the technologies that resulted in more acidic papers, which was caused mainly by the exploitation of alum (KAl(SO4)2) and rosin as sizing agents. The papers prepared by such technologies have degraded more quickly. From the 1930s various deacidification and preservation processes with basic agents have been developed. The most widespread deacidification process is with the aerosol (spray system) consisting of microscale particles MgO and perfluoroheptane (PFH) as a carrier (the so-called Bookkeeper process). The shortcomings of this process are the low dissolution of solid MgO particles and the transport to the interior of acidic paper. We have developed a theoretical two-level model of the Bookkeeper process suitable for prediction of deacidification extent. The model involves both the dissolution/reaction of the solid particles and transport of solvated ions and solid particles inside the bulk of paper. The developed model coincides with the results of the performed deacidification experiment. The model is also in good agreement with the Lucas–Washburn equation, which is usually used for the description of the penetration of a deacidifying agent into the paper. [ABSTRACT FROM AUTHOR]

A steady, incompressible, two-dimensional Sisko-nanofluid flow towards the horizontal direction with no movement in the vertical direction is considered on a stretching/shrinking surface. The power law component (Sisko model) is incorporated under the regime of the porous medium. A magnetic impact is included coming from the MHD in the surface normal direction. In addition, thermal radiation, Brownian diffusion, and thermophoresis are involved in the governing system of equations obtained from the Navier–Stokes model in two-dimensional flow systems. The PDEs are converted into the one-dimensional system using suitable transformations and solved by Galerkin weighted residual method validated with the spectral collocation method. The optimization analysis is performed on heat transfer and skin-friction factors using response surface methodology. The impact of the parameters involved in the model has been testified and is provided in graphical forms. The outcomes indicate that for the values of the porosity factor fluctuating between [0, 2.5], the velocity profile and corresponding boundary layer thickness are lesser towards the maximum value of the parameter, and the results are opposite as the parameter approaches zero. The optimization and sensitivity analysis shows that the transport of heat sensitivity towards thermal radiation, Brownian diffusion, and thermophoresis declined whenever the Nt and Nb increased from low to high and at the medium level of thermal radiation. An increment in the Forchheimer parameter increases the sensitivity of the rate of friction factor, whereas increasing the Sisk-fluid parameter has the reverse effect. Elongation processes like those of pseudopods and bubbles make use of such models. The idea is also widely used in other sectors, such as the textile industry, glass fiber production, cooling baths, paper manufacture, and many more. [ABSTRACT FROM AUTHOR]

This work aims at investigating the microwave absorption and mechanical properties of short-cutted carbon fiber/glass fiber hybrid veil reinforced epoxy composites. The short-cutted carbon fibers (CFs)/glass fibers (GFs) hybrid veil were prepared by papermaking technology, and composites liquid molding was employed to manufacture CFs/GFs hybrid epoxy composites. The microstructure, microwave absorbing properties and mechanical properties of the hybrid epoxy composites were studied by using SEM, vector network analyzer and universal material testing, respectively. The reflection coefficient of the composites were calculated by the measured complex permittivity and permeability in the X-band (8.2–12.4 GHz) range. The optimum microwave absorption properties can be obtained when the content of CFs in the hybrid veil is 6 wt% and the thickness of the composites is 2 mm, the minimum reflection coefficient of -31.8 dB and the effective absorption bandwidth is 2.1 GHz, which is ascribed to benefitting impedance matching characteristic and dielectric loss of the carbon fiber. Simultaneously the tensile strength and modulus can achieve 104.0 and 2.98 GPa, demonstrating that the CFs/GFs hybrid epoxy composites can be a promising candidate of microwave absorbing materials with high mechanical properties. [ABSTRACT FROM AUTHOR]

This study addresses one of the limiting factors for producing micro and nanofibrillated cellulose (MNFC)-containing papers: poor water removal properties. We focus on the sheet sealing phenomenon during dewatering. A modified dynamic drainage analyzer (DDA) is used to examine both multilayer and single layer forming of MNFC and pulp mixtures. It was found that a thin layer of pulp fibers on the exit layer with the grammage as low as 5 gsm was enough to significantly improve the dewatering of MNFC. For example, the dewatering rate of a furnish with 50% MNFC increased from 0.6 mL/s for a mixed system to 2 mL/s for multilayer system. However, the sheet sealing behavior was completely different when a lower proportion of MNFC was used. For the furnishes with less than 20% MNFC content, the mixed furnishes dewatered faster because the high amount of pulp fibers were able to prevent MNFC from enriching on the exit layer. Surprisingly, we found that very high final solids content (couch solids) could sometimes be achieved when MNFC was used. The highest solids contents achieved were 34 and 29% for the mixed systems. This compares to the 15–20% range typical of standard papermaking furnishes without MNFC. Overall, the results show that contrary to current thinking MNFC containing papers may lead, under some circumstances, to enhanced wire section dewatering. [ABSTRACT FROM AUTHOR]

In this paper, polyamide 12 (PA12) blends with three types of metallic fillers are tested, which differ in the type of material and its' morphology. Low content mixtures are taken into consideration (0.5, 1.0, 2.0, 5.0 wt%), since a low impact on mechanical properties along with obtaining antibacterial properties are desired. The investigation focuses on filler distribution as well as the influence on microstructural homogeneity of the base material after processing with polymer Laser Sintering. Moreover, the influence of the filler content on the mechanical properties and fracture behaviour were examined. Processability PA12 with bioactive metal fillers was confirmed, and no significant changes in ductile behaviour of PA 12 were observed. An in-depth analysis of the effect of the filler on microstructural homogeneity was conducted. [ABSTRACT FROM AUTHOR]

More than 695.7 million m3 of papermaking wastewater is discharged globally. It contains a mixture of complex pollutants, of which lignin is the major constituent (600–1000 mg/L) of papermaking black liquor, making it the second-largest energy-containing biomass globally and accounting for 47.4% and 59.4% of chemical oxygen demand (16,400 ± 120 mg/L) and chroma (3100 ± 22.32 mg/L) of papermaking wastewater. The complex process and dissolved pollutants are responsible for high pH, biochemical oxygen demand, chemical oxygen demand, total suspended solids, dark color, and toxicity. Papermaking wastewater has emerged as a substantial source of environmental pollution as the conventional wastewater treatment processes are high cost and seldom efficacious. This work introduces the shortcomings of the common treatment methods for papermaking wastewater and lignin, focusing on lignin biodegradation and discussing the metabolic pathways and application prospects of lignin-degrading microbial species. A comprehensive review of the existing lignin treatment methods has proposed that the reasonable amalgamation of biodegradation and various physicochemical techniques are environmentally friendly, sustainable, and economical. Lignin extraction from papermaking wastewater by technology combination is an effective approach to recover valuable organic materials and detoxify wastewater. This review focuses on recent breakthroughs and future trends in papermaking wastewater treatment and lignin removal, with special emphasis on biodegradation, recovery, and utilization of lignin, providing guidance for the mechanism exploration of lignin-degrading microorganisms and the optimization of high-value chemical production. [ABSTRACT FROM AUTHOR]

Cellulosic paper-based membranes reveal incalculable application values for oil–water separation owing to their renewability and biodegradability. In this work, a cellulosic paper-based membrane was prepared via papermaking and in-situ gelation. The porosity of the membrane can be tailored by pulp refining in papermaking to further adjust the flux of membranes. The as-prepared membrane can separate oil–water emulsion efficiently with separation efficiency > 98.5%. The membranes also showed good underwater oil repellency due to the hydration layer. Besides, the wet strength of the paper-based membranes was enhanced by micro-dissolved and in-situ gelation to suit the underwater separation process. The membrane is expected to be a low-cost, highly-efficient material for oily wastewater purification. This work demonstrates a new idea for the development of oil–water separation and papermaking, which provides a feasible strategy for large scale production of fully biodegradable oil–water separation membranes. [ABSTRACT FROM AUTHOR]

Recently, nanosized cellulose materials extraction is extensively interesting from the sources of sustainable materials. Cellulose nanofibrils (CNF) extraction through green bio-based materials featured as promising interest in the field of science. In this study, dimethyl sulfoxide (DMSO) was applied to examine its effectiveness in pretreating the Ficus natalensis barkcloth cellulose (FNBC) for CNF production before 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO) oxidation. The pretreatment performance of DMSO was evaluated based on the structural and morphological changes. DMSO pretreated FNBC attained the most dramatic morphological changes as compared to untreated cellulose samples. The results of the scanning electron microscope (SEM) and transmission electron microscope (TEM) shows that there is an extensive structural disruption of FNBC during the pretreatment process, which could be because of outstanding ability to eliminate non-cellulosic materials and amorphous regions from the FNBC, confirmed by the X-ray diffractometry (XRD) showing higher crystallinity values, as well as higher thermal stabilities values of pretreated FNBC samples, were also noted. Overall, this study revealed a tremendously effective and pioneer pretreatment method for fractionating FNBC, to stimulate the successive extraction of cellulose nanofibrils. Furthermore, based on the cellulose and CNF characterizations, this study showed that F. natalensis barkcloth could be considered as an alternative source of cellulose for potential value-added industrial applications such as the food industry, paper making, and biomedicines. [ABSTRACT FROM AUTHOR]

Species of Broussonetia have been essential in the development of papermaking technology. In Japan and Korea, a hybrid between B. monoica and B. papyrifera (= B. × kazinoki) known as kōzo and daknamu is still the major source of raw materials for making traditional paper washi and hanji, respectively. Despite their cultural and practical significance, however, the origin and taxonomy of kōzo and daknamu remain controversial. Additionally, the long-held generic concept of Broussonetia s.l., which included Sect. Allaeanthus and Sect. Broussonetia, was challenged as phylogenetic analyses showed Malaisia is sister to the latter section. To re-examine the taxonomic proposition that recognizes Allaeanthus, Broussonetia, and Malaisia (i.e., Broussonetia alliance), plastome and nuclear ribosomal DNA (nrDNA) sequences of six species of the alliance were assembled. Characterized by the canonical quadripartite structure, genome alignments and contents of the six plastomes (160,121–162,594 bp) are highly conserved, except for the pseudogenization and/or loss of the rpl22 gene. Relationships of the Broussonetia alliance are identical between plastome and nrDNA trees, supporting the maintenance of Malaisia and the resurrection of Allaeanthus. The phylogenomic relationships also indicate that the monoecy in B. monoica is a derived state, possibly resulting from hybridization between the dioecious B. kaempferi (♀) and B. papyrifera (♂). Based on the hypervariable ndhF-rpl32 intergenic spacer selected by sliding window analysis, phylogeographic analysis indicates that B. monoica is the sole maternal parent of B. × kazinoki and that daknamu carries multiple haplotypes, while only one haplotype was detected in kōzo. Because hybridizations between B. monoica and B. papyrifera are unidirectional and have occurred rarely in nature, our data suggest that daknamu might have originated via deliberate hybrid breeding selected for making hanji in Korea. On the contrary, kōzo appears to have a single origin and the possibility of a Korean origin cannot be ruled out. [ABSTRACT FROM AUTHOR]

Characterising cellulose nanofibre (CNF) morphology has been identified as a grand challenge for the nanocellulose research field. Direct techniques for CNF morphology characterisation exhibit various difficulties related to the material network structure and equipment cost, while indirect techniques that investigate fibre-light interaction, fibre-solvent interaction, fibre-fibre interaction, or specific fibre surface area involve relatively facile methods but may be more unreliable. Nanopaper mechanical testing is a prevalent metric for assessing fibre-fibre interaction, but is an off-line, time-consuming, and destructive methodology. In this study, an optical fibre morphology analyser (MorFi, Techpap) was employed as an on-line, high throughput, fast turnaround tool to assess micro/nanofibre pulp morphology and predict the properties of nanopaper material. Correlation analysis identified fibre content and fibre kink properties as most correlated with nanopaper strength and toughness, while fibre width and coarseness were most inversely correlated with nanopaper performance. Principal component analysis (PCA) was employed to visualise interdependent morphological and mechanical data. Subsequently, two data driven statistical models—multiple linear regression (MLR) and machine learning based support vector regression (SVR)—were established to predict nanopaper properties from fibre morphology data, with SVR generating a more accurate prediction across all nanopaper properties (NRMSE = 0.13–0.33) compared to the MLR model (NRMSE = 0.33–0.51). This study highlights that statistical methods are useful to disentangle and visualise interdependent morphological data from an on-line fibre analysis device, while regression models are also capable of predicting paper mechanical properties from CNF samples even though these devices do not operate at nanoscale resolution. [ABSTRACT FROM AUTHOR]

Paper-based electrochemical sensors provide the opportunity for low-cost, portable and environmentally friendly single-use chemical analysis and there are various reports of surface-functionalized paper electrodes. Here we report a composite paper electrode that is fabricated through designed papermaking using cellulose, carbon fibers (CF), and graphene oxide (GO). The composite paper has well-controlled structure, stable, and repeatable properties, and offers the electrocatalytic activities for sensitive and selective chemical detection. We demonstrate that this CF/GO/cellulose composite paper can be reduced electrochemically using relatively mild conditions and this GO reduction confers electrocatalytic properties to the composite paper. Finally, we demonstrate that this composite paper offers sensing performance (sensitivity and selectivity) comparable to, or better than, paper-based sensors prepared by small-batch surface-modification (e.g., printing) methods. We envision this coupling of industrialized papermaking technologies with interfacial engineering and electrochemical reduction can provide a platform for single-use and portable chemical detection for a wide range of applications. [ABSTRACT FROM AUTHOR]

The lot-sizing and cutting-stock problems arise, in general, in manufacturing industries as subsequent processes. Many authors have addressed these problems separately; however, some studies have considered integrated approaches to these problems in recent practical applications. This paper aims to introduce a new model for integrated lot-sizing, one-dimensional cutting-stock and two-dimensional cutting-stock problems. This integrated model can be used to address the papermaking process as a three-phase subsequent process, which starts from the production of jumbos and ends with the paper sheets used in daily life. The first phase of the process is modeled according to a lot-sizing problem, where the quantities of jumbos are determined to meet the demand of the entire planning horizon. The second phase is modeled as a one-dimensional cutting-stock problem, where the jumbos are cut into smaller reels. The reels are used as raw material for the third phase of the process, where they are cut again into sheets employing a two-dimensional cutting-stock problem. A heuristic algorithm that uses the column generation and relax-and-fix techniques is applied to evaluate the proposed model from a series of experiments. Gains of up 16.5% were observed compared to the solution obtained with no integration among the production phases. Additional analyses of the model behavior under multiple scenarios resulted in significant findings, as the increasing costs' reduction as more product types are considered and the use of more efficient cutting patterns resulting in reduced material waste. [ABSTRACT FROM AUTHOR]

The specific surface area (SSA) of cellulosic or lignocellulosic fibers is seldom reported in the recent literature on papermaking, despite its close relation with the degree of refining and other key pulp properties. Amidst outdated assays (Pulmac permeability test) and methods that, while accurate, are of doubtful usefulness for papermaking purposes (N2 adsorption–desorption), we suggest a methodology based on the cationic demand. A commonly used cationic polyelectrolyte, poly(diallyldimethylammonium chloride) (PDADMAC), became adsorbed onto thermomechanical pulp samples. Then, a potentiometric back titration with an anionic polyelectrolyte measured the cationic demand, expressed as microequivalents of PDADMAC per gram of pulp. Multiplying this value by the surface area of a microequivalent of polymer, considering rod-like conformation in the case of minimum ionic strength, yielded the SSA of the lignocellulosic pulp. Our system assumes that the quaternary ammonium groups were anchored through electrostatic and ion–dipole interactions. Measuring the carboxyl content allowed for discriminating between both kinds of forces. Finally, the model could be validated by plotting the estimated SSA values against the Schopper-Riegler degree, attaining high correlation coefficients (R2 ~ 0.98). Owing to the high molecular weight of the polyelectrolyte of choice (107 kDa), and more particularly in the case of fine-free pulps, SSA values estimated from the cationic demand were consistently lower than those from dye (Congo red) sorption. Instead of being a drawback, the limited diffusion of PDADMAC through fibers can enable papermakers to attain a more helpful quantification of the available surfaces in operations with low residence times. [ABSTRACT FROM AUTHOR]

In this work, the application of chemical surfactants, including cooking aids, detergents, surface sizing agents, and deinking agents as core components, is introduced in the wet end of pulping and papermaking. This method for the combined application of enzymes and surfactants has expanded, promoting technological updates and improving the effect of surfactants in practical applications. Finally, the potential substitution of green surfactants for chemical surfactants is discussed. The source, classification, and natural functions of green surfactants are introduced, including plant extracts, biobased surfactants, fermentation products, and woody biomass. These green surfactants have advantages over their chemically synthesized counterparts, such as their low toxicity and biodegradability. This article reviews the latest developments in the application of surfactants in different paper industry processes and extends the methods of use. Additionally, the application potential of green surfactants in the field of papermaking is discussed. Key points: • Surfactants as important chemical additives in papermaking process are reviewed. • Deinking technologies by combined of surfactants and enzymes are reviewed. • Applications of green surfactant in papermaking industry are prospected. [ABSTRACT FROM AUTHOR]

The properties of paper products depend on the structure of the cellulose fibres therein. Although fibre properties in virgin pulps can be modified by a refining process, this is more difficult in pulp from recovered fibre, particularly waste from office shredders that tend to shorten fibres during shredding. The shorter fibres in shredded paper make it difficult to easily reconstitute them into high-quality paper products. Moreover, because of high energy usage during the recycling process and transportation inefficiencies, there is a need to determine how to responsibly shred paper to alleviate this environmental burden. With this in mind, the influence of initial fibre length on the tensile properties of paper was investigated. Changes in initial fibre length significantly influenced many pulp and paper properties. It was found that cutting the paper into pieces with an area less than 25 mm2 caused significant changes in the important morphological parameters of the fibres and a sharp decrease in the tensile properties of the reconstituted paper. [ABSTRACT FROM AUTHOR]

Pectate lyases and pectin lyases have essential roles in various biotechnological applications, such as textile industry, paper making, pectic wastewater pretreatment, juice clarification and oil extraction. They can effectively cleave the α-1,4-glycosidic bond of pectin molecules back bone by β-elimination reaction to produce pectin oligosaccharides. In this way, it will not generate highly toxic methanol and has the advantages of good enzymatic selectivity, less by-products, mild reaction conditions and high efficiency. However, numerous researches have been done for several decades; there are still no comprehensive reviews to summarize the recent advances of pectate lyases and pectin lyases. This review tries to fill this gap by providing all relevant information, including the substrate, origin, biochemical properties, sequence analysis, mode of action, the three-dimensional structure and catalytic mechanism. [ABSTRACT FROM AUTHOR]

This study focused on the feasibility of using Fe3O4/graphene oxide (FGO) nanocomposites as heterogeneous catalysts for the advanced treatment of real industrial wastewater. FGO nanocomposites with different graphene oxide (GO) ratios were synthesized by coprecipitating iron salts onto GO sheets in basic solution. The characterization of the resulting material structures and functionalities was performed using a range of analytical techniques. A low GO loading afforded a good Fe3O4 nanoparticle dispersibility and resulted in a higher Brunauer–Emmett–Teller surface area and pore volume. The FGO nanocomposites and pure Fe3O4 were used to treat papermaking wastewater in a heterogeneous photo-Fenton process. The results suggested that the nanocomposite designated FGO1 (GO loading of 25 mg) exhibits a higher photocatalytic efficiency than other FGO nanocomposites and pure Fe3O4. A maximum chemical oxygen demand degradation efficiency of 89.6% was achieved in 80 min with 1.5 g L−1 FGO1 at pH 3. The degradation of different pollutants present in wastewater was evaluated with the aid of gas chromatography–mass spectrometry and 3D excitation–emission-matrix analysis. Inductively coupled plasma atomic emission spectroscopy and magnetic measurements confirmed that the FGO1 nanocomposites possess a low iron leachability and a high reusability. Thus, a comprehensive advanced treatment of real industrial wastewater using a magnetic FGO catalyst is demonstrated. [ABSTRACT FROM AUTHOR]

Theobroma glandiflorum and T. cacao, known as cupuaçu and cacao, respectively, are species widely used for food purposes. However, when plantations are renewed, these plants are discarded, making studies on the reuse of this material necessary. Thus, the objective of this study was to perform biometry of cellular elements and to investigate the papermaking potential of the fibers of these two species. We used the cellular element maceration technique to measure fiber and vessel element dimensions and calculated the fiber slenderness ratio, wall fraction, coefficient of flexibility and the Runkel index. According to the classification literature, the fibers of these species were of medium size, and there was a significant difference in wall thickness, with cupuaçu fibers being thicker. The values of the fiber slenderness ratio and the coefficient of flexibility were higher in cocoa, while those of wall fraction and the Runkel index were higher in cupuaçu. To conclude, the fibers of both species have papermaking potential. However, the paper manufactured with these fibers should be tested to confirm the results of this study. [ABSTRACT FROM AUTHOR]

To determine the critical component in an industry is one of the most important tasks performed by maintenance personnel to choose the best maintenance policy. Therefore, the purpose of the current paper is to develop a methodology based on integrated cloud model and extended preference ranking organization method for enrichment evaluation (PROMETHEE) method for finding the most critical component of the framework by ranking the failure causes of the system from multiple decision maker perspective. For this purpose, ranking of failure causes is performed by taking into account five factors namely chances of occurrence of failure (F0), non-detection probability (Nd), downtime duration (Dd), spare part criticality (Spc) and safety risk (Sr). In this paper, first the primary and secondary weight of decision makers are calculated based on the uncertainty degree and divergence degree, respectively, to determine overall weight using cloud model theory by converting the uncertain linguistic evaluation matrix into interval cloud matrix, and then ranking of the steam handling subunit of paper making unit in a paper mill using extended PROMETHEE. The effectiveness of the proposed methodology is explained by considering steam handling subunit of paper making unit to find the critical component. [ABSTRACT FROM AUTHOR]

An industry compatible chemo-refining approach was tested for preparation of micro-nanofibrillated cellulose (MNFC) from bleached softwood pulp using sodium meta-periodate and sodium chlorite as oxidizers followed by refining in Valley beater. SEM and FTIR analyses confirmed micro-nano scale fibrillation and chemical functional group modification in laboratory prepared MNFC, respectively. The water retention value, carboxyl content and viscosity of MNFC were found comparable with imported NFC as reference (R-NFC). To evaluate MNFC as strength enhancer for paper properties, 5% MNFC addition to bleached mixed hardwood pulp showed 6% reduction in bulk with 36%, 24% and 97% increment in breaking length, burst index and double fold of the handsheets, respectively without affecting tear index and optical properties than the control. Surface properties were also improved. Pulp drainability (37°SR) after MNFC addition was found suitable for papermaking. These laboratory results confirmed the potential of MNFC as a suitable strength additive for paper quality improvement. [ABSTRACT FROM AUTHOR]

The addition of nanofibrillated cellulose in paper production requires attention to its dispersion and retention during the paper forming process, and this is commonly facilitated by the use of retention agents. The performance of retention agents, which commonly have a cationic charge, is affected by the presence of dissolved and colloidal substances in the process water. In the process of paper production at an industrial level, especially when using recycled paper, there are a large amount of dissolved and colloidal substances in the water. A high proportion of these substances are negatively charged and are commonly referred to as anionic trash. Its presence increases the conductivity and charge density of the water, and this has a negative influence on the retention of cellulose nanofibers. In brown line paper production, some fibers have already been refined in at least one previous papermaking cycle. In this sense, recycled fibers have a reduced capacity to benefit from refining as they have suffered morphological damage. On the other hand, the addition of lignocellulosic nanofibers in the production of brown line paper has been found helpful to improve its properties and extend its lifespan. In this work the influence on the retention of nanofibers of different anionic trash levels in the water has been evaluated. The results showed its viability as a reinforcing agent in waters with high anionic trash content, through the addition of an anionic trash catching system. [ABSTRACT FROM AUTHOR]

Along with the emergence of micro and nanofibrillated celluloses and their application in papermaking, the influence of the so called fines fraction of pulps on both process and product properties has received increasing research interest in recent years. Several researchers have experimented with primary and/or secondary pulp fines to assess their effects on paper properties with not always consistent results. Our work focuses on the targeted application of the primary fines fraction of an unbleached softwood kraft pulp. The primary fines are separated from the pulp to be subsequently added to achieve blends of 5 % , 9 % and 12 % primary fines content. These blends were then refined in a PFI mill to evaluate the effect of the primary fines on refining as well as on paper properties of hand sheets prepared from these pulps. It is shown that the addition of primary fines enhances tensile strength in the unrefined and slightly refined state, while the maximum tensile strength of the highly refined reference pulp is not increased. A slightly increased dewatering resistance (Schopper Riegler) at comparable air permeability (Gurley) for a given tensile strength was also observed. The linear relationship between tensile index and apparent sheet density seems to be affected in the unrefined and slightly refined state where the breaking length of the fines enriched samples is higher for a given apparent density. [ABSTRACT FROM AUTHOR]

Microbial enzymes are the safe alternatives to chemical based bleaching of pulp in paper mills. For effective biobleaching, both hemicellulolytic and lignolytic enzymes are required. This study reports laccase (L) + xylanase (X) and laccase (L) + mannanase (M) enzyme concoctions for pulp biobleaching derived from Bacillus sp. LX and Bacillus sp. LM isolated from the decaying organic matter. All enzymes were thermo-alkali-stable, hence were suitable for their application in pulp biobleaching. When a mixture of L + X/L + M was used for mixedwood pulp biobleaching, 46.32/40.25% reduction in kappa number; 13.21/10.01% and 3.36/2.76% improvement in brightness and whiteness was achieved respectively. Moreover, no laccase mediator system was required in the current process. Significant changes in the structure of enzymatically treated pulp were also observed. All these properties make these concoctions of enzymes suitable for their application in pulp and paper mill. [ABSTRACT FROM AUTHOR]

There has been an increasing interest in recent years in isolating cellulose nanofibers from unbleached cellulose pulps for economic, environmental, and functional reasons. In the current work, cellulose nanofibers isolated from high-lignin unbleached neutral sulfite pulp were compared to those isolated from bleached rice straw pulp in making thin-film ultrafiltration membranes by vacuum filtration on hardened filter paper. The prepared membranes were characterized in terms of their microscopic structure, hydrophilicity, pure water flux, protein fouling, and ability to remove lime nanoparticles and purify papermaking wastewater effluent. Using cellulose nanofibers isolated from unbleached pulp facilitated the formation of a thin-film membrane (with a shorter filtration time for thin-film formation) and resulted in higher water flux than that obtained using nanofibers isolated from bleached fibers, without sacrificing its ability to remove the different pollutants. [ABSTRACT FROM AUTHOR]

Gas chromatography is commonly employed to detect gaseous pollutants. However, gaseous pollutants in paper mills are multicomponent and difficult to be detected and analyzed by gas chromatography. Therefore, we developed a novel autoanalyzer with an embedded supervisory system, with which multicomponent gaseous pollutants in paper mills can be detected in real time. The autoanalyzer was applied in two paper mills for the detections of the total volatile organic compounds (TVOC) and benzene at five sampling sites. The detection results show that the TVOC concentrations in two mills exceed the standard severely, especially in mill A, which can be attributed to the application of pulping and bleaching chemicals. In addition, benzene is also detected in Mill A due to benzene release from the fluorescent brighteners in the papermaking section. The large amounts of TVOC detected in the sequencing batch reactor (SBR) equalization tank of Mill A are explained by their release from the biodegradation of wastewater. [ABSTRACT FROM AUTHOR]

In this study, different methods for incorporating mixed or laminar copper microparticles (CuMPs) during papermaking were evaluated to determine the optimum paper-making process and correlate particle concentration and shape with antimicrobial activity. The addition of CuMPs during the disintegration of dry pulp stage was observed to produce a paper with uniformly distributed CuMPs, as determined through optical microscopy and UV–Vis spectroscopy analyses by measuring absorbance spectra in different areas of papers. Determination of two indices related to the concentration and distribution of copper will allow to predict the copper content in other papers. CuMP-paper samples were evaluated for structural, optical, and mechanical strength properties according to paper industry standards. Quantitative analyses by atomic absorption showed that between 24 and 39% of CuMPs were embedded in the paper fibre, independent of particle type. Finally, antibacterial activity analyses were performed according to ISO 20645 and ISO 20743. The results showed that papers with 0.30 g of incorporated CuMPs have antimicrobial activity, independent of particle morphology, with effects observed towards Gram (+) and Gram (−) bacteria and fungus. Furthermore, the evaluation of antimicrobial activity at different times of exposure to the microorganisms showed differences in effects that were dependent on the shape of the CuMPs incorporated into paper, where laminar particles exerted a sufficient effect, while no or a slight effect was observed for mixed CuMPs against Aspergillus niger. [ABSTRACT FROM AUTHOR]

This work describes the compression and failure behaviour of multi-honeycomb, re-entrant honeycomb and silicomb honeycomb structures of various core height (thickness: 10, 20 and 30 mm) reinforced with different natural fibres (flax, jute and sisal). Moulds used for manufacturing the composite cores were produced using 3D printing technique with polylactic acid (PLA). Experiments based on Taguchi design (L9) were conducted to determine the effect of each factor on the ultimate compression stress, deformation and absorption energy. The magnitude of compressive stress varied into a range of 25.32 to 36.38 MPa. Also, values of absorption of energy varied from 22.34 to 33.76 Kj/m3. It was found that thickness has a significant effect on compression properties and failure behaviour. [ABSTRACT FROM AUTHOR]

In this paper, effect of alkali-steam explosion pre-treatment on various agro-waste raw materials was evaluated for enhancing the quality of recycled paper. The alkali-steam explosion had a minimum cellulose reduction in the case of sugarcane bagasse (3.8 ± 0.21) and arecanut fibers (4.5 ± 0.83%) and identified as a good fiber sources for paper making in terms of strength and final quality of recycled papers. X-ray diffraction pattern study exhibited that there was an enhanced intensity of cellulose content. Coloring on recycled paper with natural pigments could be used as a packing material with bactericidal activity. This forms the first report on the application of stable pigments for value addition in paper industry which increases the marketability of recycled paper. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Eliminating congestion in China's papermaking and paper products industry: from both the perspective of increasing and decreasing inputs" published in the Journal of Productivity Analysis. The authors acknowledge that there is overlap and duplication between their paper and a previously published paper, and they apologize for not acknowledging this in their article. The correction notice provides the correct citation for the original article and states that the authors regret the lack of transparency regarding the similarities between the two papers. [Extracted from the article]

Anionic pectic substances in whitewater from papermaking are detrimental to machine operation and product quality. Pectinase was immobilized on pulp fiber using cationic polyacrylamide with layer-by-layer method to obtain bound enzyme with tunable activity and good performance for wastewater treatment. It was revealed that high charge density and low molecular weight for cationic polyacrylamide were advantageous for enzymatic activity. During the layer-by-layer adsorption process, the enzymatic activity of the immobilized enzyme increased nearly linearly with the layer number from 983 to 3074 U/g until the fourth layer. The stability of the four-layer immobilized enzyme was improved. The multilayer immobilized enzyme exhibited good reusability and storage stability compared with monolayer enzyme. At dosage of 10 U/mL, the cationic demand of the whitewater samples was reduced by 15% using four-layer immobilized enzyme. The results indicated a potential route to prepare immobilized enzyme with good performance for wastewater treatment in papermaking industry. [ABSTRACT FROM AUTHOR]

Spindle-like CaCO3 crystals with controllable sizes for papermaking were successfully prepared using CO2 (8% CO2/N2 mixture gas) and calcium carbide residue (CCR) waste, a by-product of acetylene gas and polyvinyl chloride production, as the raw materials by an atomization method at room temperature. The influences of solution concentration, reaction temperature, and gas/liquid flow rate ratios on the properties of the CaCO3 crystal were systematically investigated, and a possible atomization mechanism was proposed. The size of the as-prepared CaCO3 crystal with pure calcite phase was turned from 4.71×4.02 µm to 1.82×1.12 µm by adjusting the reaction conditions. The application of the as-prepared CaCO3 crystals from CCR waste as a filler for papermaking was explored. The R475 blue light whiteness of paper was increased from 77.3 to 80.6 with 11.4% CaCO3 crystals. [ABSTRACT FROM AUTHOR]

Bacterial nanocellulose (BNC) is a unique natural nanomaterial that shares very few similarities with other natural or industrially produced nanomaterials. BNC can be produced by a variety of bacteria, as a survival aid in different ecological niches. BNC is traditionally produced by static or shaking culture methods, and the 'mother vinegar', or biofilm, is a typical example of this product after static vinegar fermentation. BNC has great potential in biomedicine, and recent studies have also demonstrated its use in the papermaking industry. It has nanoscale fiber size and large numbers of free hydroxyl groups, which ensure high inter-fiber hydrogen bonding. Thus, BNC has great potential as a reinforcing material, and is especially applicable for recycled paper and for paper made of nonwoody cellulose fiber. As well as enhancing the strength and durability of paper, modified BNC shows great potential for production of fire resistant and specialized papers. However, the biotechnological aspects of BNC need to be improved to minimize the cost of its production, and to thus make this process economically feasible. [ABSTRACT FROM AUTHOR]

Generated in the pulp and paper production process, cellulosic pulp fines are fibrous cellulosic materials capable of passing a 200 mesh screen. Processed pulp fines remain in the pulp and affect pulp and paper sheet properties. Their specific morphology promotes interactions with fibers and alters sheet properties. Nevertheless, the 3D distribution of fines in paper sheets has not been revealed so far. Localizing fines within a matrix of fibers is challenging since both elements have the same chemical composition and fines have small dimensions. It is required to increase the contrast of pulp fines, while avoiding any alteration of initial fines morphology. In this study, fines were first separated and labeled with Rhodamine B isothiocyanate, a fluorescent dye. Labeled fines were blended with pulp at different concentrations and paper sheets were produced from each mixture. Prior to imaging, pulps and handsheets were characterized by standard pulp and paper tests and compared with references, showing no significant differences between sheets containing labeled and untreated fines. Thus, mechanical and physical tests indicated that no, or only minor alteration of fines properties by the labeling process occurred. We then applied two imaging techniques to detect the labeled pulp fines in the paper network, namely confocal laser scanning microscopy and multiphoton microscopy, visualizing the 3D distribution of fluorescent fines within the fiber network. The results obtained also allowed a differentiation between morphologically different fines showing fiber fragments more attached to single fibers whereas more fibrillar fines concentrate in fiber–fiber joints, thereby strengthening bonding. [ABSTRACT FROM AUTHOR]

Cationized fibers and other kinds of chemically modified fibers impart many advantages in papermaking, but unfeasibly long reaction times are necessary to attain acceptable degrees of substitution, due to the low reactivity of bleached kraft pulps. In this work, different aqueous pretreatments were tested in order to activate cellulose towards a 60 min-long etherification with a quaternary ammonium reagent. Severe decrystallization treatments, namely alkalization with NaOH 20%, NaOH/urea or FeTNa, conducted to the best reactivity results (substitution from 2 to 10%), but the fiber properties were harshly affected. Pretreatments involving H3PO4 at different concentrations were also performed, with distinct results, from unnoticeable effects at 20% to amorphization and excessive depolymerization at 80%. Finally, aqueous ammonium thiocyanate was tested as activator and had little effect on fibers, although the addition of ammonia resulted in high degrees of substitution, while maintaining the pulps' capability to retain inter-fiber water and cellulose I as the prevalent allomorph. [ABSTRACT FROM AUTHOR]