• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.32 no.1
• /
• pp.48-56
• /
• 2000

The objective of this study was to investigate the enzymatic deinking technology. Office recycled papers such as computer printed out(CPO) and white ledger(WL) were used in the evaluation of four different deinking conditions ; alkaline deinking , neutral deinking and enzymatic deinking at alkaline and neutral pH. Filltering pads were prepared after flotation deinking to measure brighteness gain and ink removal efficiency. Three different surfactants were also used in the evaluation of deinking efficiency including surface chemical properties by measuring foam height and stability, surface tension and cloud point of views. The results indicated that the neutral deinking method with enzyme and surfactant addition showed highest deinking efficiency of office recycled papers.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2006.06b
• /
• pp.257-263
• /
• 2006

This paper examines the physico-chemical properties and structural features of thio lignin and alcohol lignin preparations extracted from fast-growing poplar wood. The lignin preparations were characterized using UV, IR and alkaline nitrobenzene oxidation methods. The yield was higher in thiolignin due to its preparation from wood under drastic alkaline conditions and almost the total amount of alkaline degraded lignin was precipitated except acid soluble lignin. In case of ethanol lignin, structural modifications were comparatively less and form a cream colored lignin more or less similar to its original natural color. The methoxyl values were higher due to syringyl unit present in hard wood lignin in addition to guaicyl unit present in soft wood. The higher values of methoxyl content of isolated lignin revealed that it was built up of high syringyl units. The elementary analysis, methoxyl group and hydroxyl groups were presented by $C_{9}$ formula indicated that it was made up of phenyl propane monomers. Nitrobenzene oxidation of thio lignin and ethanol lignin yield more or less the chromatograms of similar pattern, except difference in relative percentage. The ultra violet spectra of lignins were quite similar, irrespective of the source and method of isolation. Infrared spectroscopy studies of poplar deltoides, thio and ethanol lignin shown different absorption bands which have been utilized for structural investigations.

• Mycobiology
• /
• v.44 no.4
• /
• pp.260-268
• /
• 2016

Regulation of alkaline-resistant laccase from Perenniporia tephropora KU-Alk4 was proved to be controlled by several factors. One important factor was the initial pH, which drove the fungus to produce different kinds of ligninolytic enzymes. P. tephropora KU-Alk4 could grow at pH 4.5, 7.0, and 8.0. The fungus produced laccase and MnP at pH 7.0, but only laccase at pH 8.0. The specific activity of laccase in the pH 8.0 culture was higher than that in the pH 7.0 culture. At pH 8.0, glucose was the best carbon source for laccase production but growth was better with lactose. Low concentrations of glucose at 0.1% to 1.0% enhanced laccase production, while concentrations over 1% gave contradictory results. Veratryl alcohol induced the production of laccase. A trace concentration of copper ions was required for laccase production. Biomass increased with an increasing rate of aeration of shaking flasks from 100 to 140 rpm; however, shaking at over 120 rpm decreased laccase quantity. Highest amount of laccase produced by KU-Alk4, 360 U/mL, was at pH 8.0 with 1% glucose and 0.2 mM copper sulfate, unshaken for the first 3 days, followed by addition of 0.85 mM veratryl alcohol and shaking at 120 rpm. The crude enzyme was significantly stable in alkaline pH 8.0~10.0 for 24 hr. After treating the pulp mill effluent with the KU-Alk4 system for 3 days, pH decreased from 9.6 to 6.8, with reduction of color and chemical oxygen demand at 83.2% and 81%, respectively. Laccase was detectable during the biotreatment process.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.31 no.3
• /
• pp.83-89
• /
• 1999

Bast fibers of paper mulberry ( Broussonetia Kazinoki Sieb) were cooked with a weak alkaline salt, potassium carbonate which has been known as a major inorganic component of the traditional lye, and its cooking characteristics were investigated . The bast fiber was easily cooked by potassium carbonate. The pulp yield was rapidly decreased up to 20-30 mol of potassium carbonate, but the Kappa number was slowly decreased with increasing of potassium carbonate. The potassium carbonate pulps were easily defibered at low cooking chemical charge of 25mm on and high pulp yield of about 80%. These results were confirmed that pectin was easily removed during the potassium carbonate cooking. In contrast, when sodium carbonate was used as a cooling agent, the bast fiber was only partially defibered. Thus, sodium carbonate was a less effective cooling chemical of the bast fiber. The results of this experiment indicated that potassium carbonate could not only be used as a good cooling agent of bast fiber, but also as an alternative agent of sodium hydroxide.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.35 no.4
• /
• pp.34-41
• /
• 2003

The effect of wettability of deinking agents which formed with various nonionic surfactants against the pulp fibers and ink particles were studied, And the effect of flotation processes on the deinking were also investigated. The wettabilities of the deinking agents against the water and ink particles were measured by Washburn tube and sessile drop techniques, respectively. As the water absorption increased (i.e., hydrophilicity increased), the ink removal increased, which indicates that the ink removal is strongly affected by the detachment process due to the swelling of the pulp. Also, when the contact angle of air/ink/deinking agent increased, the hydrophobicity of the ink particles increased, the efficiency of the ink removal and the brightness increased.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2006.06b
• /
• pp.349-352
• /
• 2006

The conventional pulping processes in Iran were reviewed in this paper. On account of forest resources restriction, a considerable extent of non-harvestable hardwood forests, the possibility of accessable non-wood resources and Poplar fast-growing species for using in pulp and paper industry was investigate. The cultivated area and abundance of each mentioned raw material (Wheat Straw, Sugarcane Bagasse, Poplars) were specified and the quality of their produced papers were compared in strength and opacity properties. Spruce species data was used for experiments comparisons. Regarding to environmental pollutions, low yield, inflexibility in wood and non-wood species resulted from the existent conventional processes of paper manufacturing, APMP is recommended due to high quality paper, desirable opacity properties, high yield and also the usage for all the raw materials.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.32 no.3
• /
• pp.65-74
• /
• 2000

This study was carried out to acquire basic data necessary for the use of rice-straw chemical pulp. It investigated the proper bleaching conditions when rice-straw chemical pulps(alkaline sulfite-Na2S2O4 pulp) were bleached with the various kinds of bleaching agents. And physical properties of bleached pulps were tested. The results of this study were as follows; 1, The proper conditions of chlorine sequence were determined to be 4% concentration of chlorine 25$^{\circ}C$ of reaction temperature and 50 minutes of reaction time. 2. For calcium hypochlorite sequence the proper conditions of chemical concentration reac-tion temperature and reaction time were 3% 25$^{\circ}C$ and 20 minutes respectively. 3. For chlorine dioxide sequence the proper conditions were 1% concentration of chlorine dioxide 70$^{\circ}C$ of reaction temperature and 2hr. of reaction time. 4. The proper conditions of hydrogen peroxide sequence were 1.5% concentration of hydro-gen peroxide 70$^{\circ}C$ of reaction temperature and 1hr. of reaction time respectively. 5. When the rice-straw chemical pulp were bleached with four kinds of bleaching agents methioned above in the proper conditions respectively brightnesses were the order of chlorine dioxide calcium hypochlorite, chlorine, hydrogen peroxide. And strengthes of pulps bleached with chlorine dioxide and hydrogen peroxide were higher than those of pulps bleached with other bleaching agents.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.27 no.1
• /
• pp.151-160
• /
• 2000

The effect of concentration as factor in cytotoxicity, protein synthesis and alkaline phosphatase activity was compared for pulpotomy medicaments (formaldehyde, formocresol, paraformaldehyde, ferric sulfate) Human pulp fibroblasts were exposed to a range of concentrations(0.01, 0.05, 0.10, 0.25, 0.50, $1.00{\mu}l/ml$) of each agents, for period of 24hrs. The cell activities were evaluated by MTT assay, protein assay and alkaline phosphatase activity examination. The results as follows : 1. After 24hrs culture, pulp fibroblasts adding formaldehyde, formocresol and paraformaldehyde were suppressed cell activities with concentration increasing, but, no depression of cell activities by ferric sulfate. No significant difference was in formaldehyde, formocresol and paraformaldehyde. 2. Protein synthesis by pulpotomy agents were not significant difference in pulp fibroblasts but protein synthesis were a little decreased by paraformaldehyde. 3. Alkaline phosphatase activity was a little decreased by pulpotomy medicaments.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.41 no.4
• /
• pp.33-42
• /
• 2009

This study was performed to evaluate the hexavalent chromium content in flexography inks and organic pigments used as colorants for the ink. The digestion of sample was carried out under alkaline condition, and the content of soluble hexavalent chromium extracted from samples was determined by UV-visible colorimetric analysis method after alkaline digestion. Duplicate sampling system to obtain two digested samples, was applied in this study. To determine the hexavalent chromium content in the flexography ink and organic pigment colorimeteric analysis was employed. Because the organic pigment is the main ingredient of flexography ink it is important to remove the errors associated with the colorant of the ink in colorimetric determination. The duplicate sampling system allowed us to correct the errors associated with the colorimeteric measurement. The additional filtration was found an essential step to exclude colorimeteric error derived from the various precipitates. The soluble hexavalent chromium content in flexography inks was generally less than 5 ppm. Yellow, violet and some magenta colors showed higher soluble hexavalent chromium contents. The content of hexavalent chromium in organic pigments was greater than flexography inks, and yellow, violet and some magenta pigments contained greater amount of hexavalent chromium, which indicated that the hexavalent chromium in inks derives from the colorants. The soluble hexavalent chromium content in linerboards were below 1 ppm, and no hexavalent chromium was detected in UKP. Results suggested that flexography ink is the main factor to cause hexavalent chromium in linerboard and organic pigments.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.38 no.3 s.116
• /
• pp.13-22
• /
• 2006

The analogs of cyclic hydroxamic acids containing N-OH group have been proposed to play effective laccase-mediators in kraft pulp bleaching with laccase/mediator system. The existing mediators (NHA, 1-HBT, VA), the best laccase-mediators reported so far, and selected several analogs of cyclic hydroxamic acids were evaluated as a laccase-mediator for kraft pulp bleaching. It was found that NHA was the most effective mediator for the Trychophyton sp. LKY-7 laccase (TrL) in kraft pulp bleaching with TrL/mediator system, increasing about 10% ISO of brightness and decreasing about 2.8 of kappa number after alkaline-peroxide bleaching. Of the cyclic hydroxamic acidstested, the NHP.1(N-hydroxypyridone analog) was shown to enable TrL to effectively degrade lignin in kraft pulp bleaching, demonstrating approximately similar effect with that of NHA. However, the effect of substituent patterns of cyclic hydroxamic acid analogs in kraft pulp bleaching was not observed. The inhibitions of NHA and NHP.1 on TrL were not exhibited in TrL/mediator system. As a new mediator for TrL, NHP.1 was considered to be able to use in kraft pulp bleaching with TrL/mediator system.