Fractionation of epidermal cells from wheat straw pulp by flotation

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 229-235
Author(s):  
MIKKO KARJALAINEN ◽  
ARI ÄMMÄLÄ ◽  
PÄIVI ROUSU ◽  
JOUKO NIINIMÄKI
Keyword(s):  
Wheat Straw ◽  
Cell Types ◽  
Strength Properties ◽  
Epidermal Cells ◽  
Raw Material ◽  
Paper Strength ◽  
Paper Properties ◽  
Vessel Elements ◽  
Wide Availability ◽  
Wheat Straw Pulp

The wide availability of wheat straw makes it a promising raw material for various fiber products, but its heterogeneity makes it a challenging material to use. In addition to reducing paper properties, some cell types cause processing problems such as silicate deposition and poor dewatering. The aims of this work were to examine the fractionation tendency of wheat straw pulp cells in flotation and to determine the effect of fractionation on paper strength properties. A cell type categorization based on automatic optical fiber analysis was used to assess fractionation. The results showed that epidermal cells can be selectively enriched from unbleached wheat straw pulp by flotation and other short cells had a tendency to become enriched in the overflow fraction. The underflow fraction consisted mostly of fibrous material, as well as vessel elements and long parenchyma cells. Removal of the epidermal cells from pulp will reduce its silicate content and improve the strength properties of the paper.

scholarly journals Study of the mechanical behavior of recycled fibers. Applications to papers and paperboards.

2018 ◽  
Author(s):  
Imtiaz Ali
Keyword(s):  
Surface Friction ◽  
Strength Properties ◽  
Size Exclusion ◽  
Ultrastructural Changes ◽  
X Rays ◽  
Paper Strength ◽  
Electron Microscopic ◽  
Paper Properties ◽  
Recycled Pulp ◽  
Fibre Width

Incorporation of recycled fibres in high value paper products can reduce cost and environmental loads. Papermaking potential of cellulosic fibres decreases with recycling. The phenomenon of fibre hornification during pressing and drying is normally held responsible for the loss in strength. To study the impacts of recycling on pulp, fibre and paper properties some non conventional characterisation techniques like fibre saturation point, X-rays microtomography, environmental scanning electron microscopic observations, atomic forcemicroscope (PeakForce QNM mode) and inverse size exclusion chromatography(ISEC) were used. In order to achieve good reproducibility of ISEC measurements,a semi-automatic column fabrication pilot system was built. The techniques were first validated on refining process before being applied to the recycling process. In this study, it was found that fibre hornification alone cannot fully explain loss in strength during recycling. The loss in strength is much more complex and it is required to understand the morphological and ultrastructural changes associated with recycling. Fibre width, cell wall thickness,curl, kink, irregularities decreased during recycling. Fibre became hard and brittle in dry state. Number of weak points in the fibre wall were increased initially and in the later recyclings. The increase in wet breaking length indicates increased surface friction and capillary forces with recycling. Decrease in bonded area during first recycle may be caused by the loss of fines and fibre flexibility whereas the increase afterwards may be linked to the lumen collapse.The strength of fibres did not decrease with recycling as shown by zero-span breaking lengths therefore the quality of bond may be deteriorated. It was thought that the partially delaminated P/S1 layers may be responsible for the loss of paper strength. It is suggested since the significant change is associated with the pressing and drying of never dried pulp therefore the drying process needs to be revisited. The delaminated layer should be restored so as to increase the recyclability of the recovered fibres for high value paper. Influence of recycled pulp blends on physical properties of paper was also studied. It was revealed that small quantity of recycled pulp can be used without significantly affecting the mechanical strength properties.

The influence of screening process parameters on paper properties produced from wastepaper

2020 ◽  
Vol 110 ◽  
pp. 16-24
Author(s):  
Anhelina Nikalaichyk ◽  
Edyta Małachowska
Keyword(s):  
Surface Properties ◽  
Process Parameters ◽  
Raw Material ◽  
Paper Strength ◽  
Recycled Paper ◽  
Cellulose Fibres ◽  
Screening Process ◽  
Paper Properties ◽  
Paper Surface ◽  
The Impact

The influence of screening process parameters on paper properties produced from wastepaper. Wastepaper processing is of pivotal importance for environmental protection; it is also crucial for the economy and the management of raw materials. Not only does recycling save space at landfills, it also saves an extremely valuable raw material used for paper production, i.e. wood. Unlike primary pulps, however, wastepaper contains much more than just cellulose fibres and fillers. The fact that recycled paper contains many contaminants, such as metal staples, paper clips, plastic film, glass fragments, and others, makes it necessary to develop a much more complex pulp preparation systems compared to the ones used for primary pulps. Contaminants affect not only the usable quality of paper made of wastepaper, but also cause the wear and tear of paper processing equipment. Thus, the purifying and screening of secondary pulps for further processing is very important. Considering the above, the authors’ objective was to study the impact of the width of screen slots on paper properties if produced from screened wastepaper pulp. Paper strength and paper surface properties were used as the main evaluation criteria. White and mixed wastepaper was used as research material. Based on the tests, the screen slot width was found not to have any significant impact on either paper mechanical strength or paper surface properties.

Composite filler by pre-flocculation of fiber fines and PCC and its effect on paper properties

2020 ◽  
Vol 35 (2) ◽  
pp. 251-260
Author(s):  
Hyun Kang ◽  
Jong Myoung Won ◽  
Byoung-Uk Cho
Keyword(s):  
Strength Properties ◽  
Ash Content ◽  
Paper Strength ◽  
Precipitated Calcium Carbonate ◽  
Paper Properties ◽  
Loading Method ◽  
Retention Aids ◽  
Composite Filler ◽  
Filler Retention ◽  
Better Than

AbstractA composite filler was developed by pre-flocculation of fiber fines and precipitated calcium carbonate (PCC) particles with flocculants such as cationic polyacrylamide (cPAM) and bentonite. The composite filler was compared with a conventional loading method in terms of physical properties of handsheet and filler retention. The handsheets using the composite filler showed higher strength properties than that using a conventional loading at a similar paper ash content level, implying that paper ash content can be increased maintaining same level of paper strength. Optical properties such as opacity and brightness of the paper with the composite were quite similar with the paper with the conventional loading. Filler retention of the composite filler was slightly higher than that of the conventional loading even though retention aids were not used for the composite filler. Paper formation of the composite filler was better than the case of the conventional loading. However, the sheet with the composite filler showed lower bulk than that with the conventional loading. Conclusively, the composite filler technology by pre-flocculation of fines and filler has a potential to be utilized to produce a high loaded paper.

Circular action treatment (CAT): a new strategy for mechanical treatment of old corrugated container III

2019 ◽  
Vol 34 (3) ◽  
pp. 362-370
Author(s):  
Jin-Doo Kim ◽  
Tai-Ju Lee ◽  
Jae-Hoon Lee ◽  
Jeong-Yong Ryu ◽  
Jong-Myoung Won
Keyword(s):  
Paper Mill ◽  
Mechanical Action ◽  
Strength Properties ◽  
Raw Material ◽  
Paper Strength ◽  
Mill Scale ◽  
Fiber Properties ◽  
Higher Power ◽  
Strength Based ◽  
New Strategy

Abstract OCC have been the most important raw material for production of papers for industrial grades. The quality of OCC fibers have been deteriorated by repeated recycling process. In order to overcome the defects of OCC CAT has been developed as a new strategy for old corrugated container (OCC), which could generate mild mechanical action. The effect of CAT was proven through the previous researches which showed the increase of the fiber properties, such as WRV, freeness, and strength properties, and positive effect on paper strength. Based on the results, mill-scale application of CAT was performed at a linerboard mill located in Republic of KOREA. In this paper, mill-scale CAT was designed with higher power and dimension compared to the previous lab-scale CAT, which was equipped at the screw press outlet in a papermaking process. Fiber properties, final product quality, and energy consumption were analyzed with the installation of mill-scale CAT. Freeness and WRV were improved with an increase of passing time, and mean fiber length was constant simultaneously. In terms of process runnability, there was no problem during the test. Furthermore the outstanding achievement was found that the energy could be saved using CAT by around 30 % compared to double-disc low-consistency refining. Consequently CAT could be a new alternative for treatment of OCC without any troubles.

Energy saving potential of high yield pulp (HYP) application by addition of small amounts of bleached wheat straw pulp

Holzforschung ◽  
2011 ◽  
Vol 65 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Hongjie Zhang ◽  
Zhirun Yuan ◽  
Yonghao Ni
Keyword(s):  
Energy Saving ◽  
Wheat Straw ◽  
Strength Property ◽  
Energy Input ◽  
Practical Implication ◽  
Strength Properties ◽  
Refining Process ◽  
High Yield ◽  
Energy Saving Potential ◽  
Wheat Straw Pulp

Abstract High-yield pulp (HYP) has found wide applications in many paper grades. Usually, the strength properties of HYP must be improved and its freeness fine-tuned before sending it for paper machining, by means of refining at a low consistency, which requires energy. In this study, the possibility of avoiding refining of HYP was investigated by adding low percentages of refined and bleached wheat straw pulp (BWSP) to a HYP-containing mixture. The results show that the strength properties of a HYP and a hardwood kraft (HWKP) mixture can be improved with approximately 10% refined BWSP. In this manner, refining energy of 20 kWh t-1 is needed, and the pulp quality is improved to a similar level to that obtained from the same pulp mixture refined with an energy input of 70 kWh t-1. This approach also works for 100% HYP. The practical implication is that only a small percentage of refined BWSP is needed to improve the strength property of a HYP or HYP/HWKP mixtures, so that less refining energy is required in the low-consistency refining process.

Modification in the properties of paper by using cellulase-free xylanase produced from alkalophilic Cellulosimicrobium cellulans CKMX1 in biobleaching of wheat straw pulp

2015 ◽  
Vol 61 (9) ◽  
pp. 671-681 ◽  
Author(s):  
Abhishek Walia ◽  
Preeti Mehta ◽  
Shiwani Guleria ◽  
Chand Karan Shirkot
Keyword(s):  
Wheat Straw ◽  
Paper Industry ◽  
Strength Properties ◽  
Pulp And Paper ◽  
Mushroom Compost ◽  
Bleached Pulp ◽  
Cellulosimicrobium Cellulans ◽  
Wheat Straw Pulp ◽  
Pulp Strength ◽  
Cellulosimicrobium Cellulans Ckmx1

Alkalophilic Cellulosimicrobium cellulans CKMX1 isolated from mushroom compost is an actinomycete that produces industrially important and environmentally safer thermostable cellulase-free xylanase, which is used in the pulp and paper industry as an alternative to the use of toxic chlorinated compounds. Strain CKMX1 was previously characterized by metabolic fingerprinting, whole-cell fatty acids methyl ester analysis, and 16S rDNA and was found to be C. cellulans CKMX1. Crude enzyme (1027.65 U/g DBP) produced by C. cellulans CKMX1, having pH and temperature optima of 8.0 and 60 °C, respectively, in solid state fermentation of apple pomace, was used in the production of bleached wheat straw pulp. Pretreatment with xylanase at a dose of 5 U/g after pulping decreased pulp kappa points by 1.4 as compared with the control. Prebleaching with a xylanase dose of 5 U/g pulp reduced the chlorine charge by 12.5%, increased the final brightness points by approximately 1.42% ISO, and improved the pulp strength properties. Xylanase could be substituted for alkali extraction in C–Ep–D sequence and used for treating chemically bleached pulp, resulting in bleached pulp with higher strength properties. Modification of bleached pulp with 5 U of enzyme/g increased pulp whiteness and breaking length by 1.03% and 60 m, respectively; decreased tear factor of pulp by 7.29%; increased bulk weight by 3.99%, as compared with the original pulp. Reducing sugars and UV-absorbing lignin-derived compound values were considerably higher in xylanase-treated samples. Cellulosimicrobium cellulans CKMX1 has a potential application in the pulp and paper industries.

Filler modified by a sequential encapsulation and preflocculation method and its effect on paper properties

2020 ◽  
Vol 35 (1) ◽  
pp. 89-95
Author(s):  
Nannan Chen ◽  
Lijun Wang ◽  
Junchao Wen ◽  
Xianping Yao ◽  
Wenyan Zhao
Keyword(s):  
Filler Content ◽  
Strength Properties ◽  
Paper Strength ◽  
Cationic Starch ◽  
Paper Properties ◽  
Polyelectrolyte Complexes ◽  
New Methods ◽  
Charge Potential ◽  
Filler Retention ◽  
Anionic Polyacrylamide

AbstractIncreasing the filler content of sheet tends to decrease filler retention and paper strength properties. To overcome this problem and make better use of fillers, development of new methods on filler modification has never been stopped. In this study, filler modification was carried out by sequentially adding an anionic polyacrylamide, a cationic starch and a cationic polyacrylamide. It is believed that in this process, multiple polyelectrolyte complexes are formed which can not only encapsulate filler particles but also preflocculate the particles. The results showed that, compared to the single preflocculation treatment, the sequential encapsulation and preflocculation (SEP) treatment brought significantly larger particle size and higher surface charge potential of the filler, thus higher filler retention was achieved. When the modified fillers were used for papermaking and paper ash contents were controlled at the same level, the SEP modification was better in improving the tensile index, internal bond strength and tearing index of paper than the single preflocculation method, in addition, it maintained better paper formation, caused insignificant change on opacity of paper. It is believed that this newly developed SEP method is worthy of being applied to industrial scales in making various grades of filled paper.

scholarly journals Complete characterization of wheat straw (Triticum aestivum PBW-343 L. Emend. Fiori & Paul.) – A renewable source of fibers for pulp and paper making

BioResources ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 154-177
Author(s):  
Shalini Singh ◽  
Dharm Dutt ◽  
C. H. Tyagi
Keyword(s):  
Triticum Aestivum ◽  
Wheat Straw ◽  
Strength Properties ◽  
Complete Characterization ◽  
Epidermal Cells ◽  
Pulp Yield ◽  
Vascular Bundles ◽  
Paper Making ◽  
Tear Index ◽  
Cooking Conditions

Triticum aestivum PBW-343 is grown in most of the regions of India, and it is one of the renewable sources most suitable for papermaking. Anatomical studies illustrate that vascular bundles near the periphery contain a strong sheath of sclerenchyma cells, which constitutes about 80% of the fibers. The total fibers in wheat straw are about 39.20%, and parenchyma and epidermal cells account for 32.10, and 23.56%, respectively, of the total cells. The dimensions of wheat straw fibers are: average fiber length 1.18 mm, fiber width 13.60 µm, lumen diameter 5.68 µm, and cell wall thickness 3.96 µm. The dimensions of non-fibrous cells are: parenchyma 445×124 µm, vessels 96×57 µm, and epidermal cells 390×38 µm, which lie between the corresponding values for rice straw, and bagasse. Flexibility coefficients and Runkel ratio of wheat straw fires are quite comparable to bamboo. The low lignin contents of wheat straw reflect that it requires mild cooking conditions; however, hemicelluloses are on higher side. Addition of AQ under optimum soda cooking conditions improves pulp yield by 0.75%, and lowers kappa number by 26.1%. Optimum strength properties are obtained at 45±1 oSR except tear index, which declines with increased refining. The fine contents are much higher, and relatively comparable to Eucalyptus tereticornis in terms of curl index and kinks per mm.

Multistage fiber fractionation of softwood chemical pulp through smooth-hole screen cylinders and its effects on paper properties

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 259-267 ◽  
Author(s):  
S. JUNAID S. QAZI ◽  
MASITA MOHAMAD ◽  
JAMES A. OLSON ◽  
D. MARK MARTINEZ
Keyword(s):  
Physical Properties ◽  
Strength Properties ◽  
Operating Conditions ◽  
Raw Material ◽  
Optimum Operating ◽  
Aperture Size ◽  
Fractionation Process ◽  
Small Aperture ◽  
Paper Properties ◽  
Fiber Fractionation

Pressure screens are used to fractionate fibers on the basis of aspect ratio to obtain high value longfiber rejects and less desirable fines-rich accepts. Fiber fractionation is more practical and of maximum economic and commercial benefits when a mill can make use of all obtained fractions. We have demonstrated the potential of upgrading the reject fraction through a multistage fractionation process of a northern bleached softwood kraft pulp while isolating the remaining low-value pulp to be used as a raw material for a novel fiber-based product. The optimum operating conditions such as volumetric reject ratio, Rv; aperture velocity, Vs; and screen aperture size to carry out efficient fractionation were determined for the screens with 0.5-mm, 0.8-mm, and 1.0-mm apertures. This work shows that a high fines percentage in the accept fraction and increased fiber length in the reject fraction can be obtained when operating the pressure screen at a higher Rv and lower Vs using the screen cylinder with the small aperture size (0.5 mm). Feed and fractionated streams of pulp were used to study the effects on the physical properties of paper. Handsheets were made for strength properties of the unfractionated and fractionated pulps for comparisons. Significant improvements in the physical properties were observed after the removal of fines.

Research on Biological Modification of Pulp to Improve the Strength of Paper

2013 ◽  
Vol 848 ◽  
pp. 334-337
Author(s):  
Ai Yun Long ◽  
Chuan Shan Zhao ◽  
Wen Jia Han ◽  
Yi Fei Jiang
Keyword(s):  
Control Sample ◽  
Strength Properties ◽  
Raw Material ◽  
Paper Strength ◽  
Optimum Conditions ◽  
Wet Strength ◽  
Tensile Index ◽  
Pulp Consistency ◽  
Pulp Properties ◽  
Biological Modification

Based on the domestic OCC pulp as raw material, it was found that the optimum conditions for laccase treatment were: the concentration of laccase 16U/g dry pulp, the pulp consistency 5%, temperature 50 °C, pH=5.0 and reaction time 90min. OCC treated with laccase alone can improve paper strength properties. The dry tensile index and wet tensile index of the control sample were 21.80 Nm/g and 0.22 Nm/g, respectively. The dry tensile index and wet tensile index after OCC treated with laccase alone were 23.36 Nm/g and 0.28 Nm /g. Comparing to the control pulp, the dry tensile index and wet tensile index of OCC treated with laccase were increased by 6.88% and 27.3%, respectively. At the same time, the laccase system can obviously improve the strength of the pulp properties with adding the mediator, especially using histidine, the dry and wet strength of paper was largely improved.

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