• Journal of the Korean Wood Science and Technology
• /
• v.41 no.2
• /
• pp.87-99
• /
• 2013

Waste paper stands for the major biodegradable organic fraction of most of municipal solid waste. The potential of waste paper for glucose production was investigated in this current work. The pretreatment was accomplished by first subjecting waste paper to disintegration time (30 s), followed by ink removal of disintegrated waste paper using an deinking agent. Concentrated acid hydrolysis of waste paper with sulfuric acid was optimized to maximize glucose conversion. The concentrated acid hydrolysis conditions for waste paper (disintegrated time: 30 s, deinking agent loading : 15 ml) were optimized by using central composite design and response surface methodology. The optimization process employed a central composite design, where the investigated variables were acid concentration (60~80%), loading sulfuric acid (1~5 ml) and reaction time (1~5 h). All the tested variables were identified to have significant effects (p < 0.05) on glucose conversion. The optimum concentrated acid hydrolysis conditions were acid concentration of 70.8%, loading sulfuric acid of 3.2 ml and a reaction time of 3.6 h. This research of concentrated acid hydrolysis was a promising method to improve glucose conversion for waste paper.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.3
• /
• pp.37-43
• /
• 2001

The bleach efficiency between PY and YP bleaching of pulps, which were deinked in neutral (cellulase) and alkaline (NaOH, NaOH/${Na_2}{SiO_3}$) ranges, and were treated on kneader, was compared in this study. The brightness of pulps (84.8~88.4% ISO) which were deinked in alkaline or neutral ranges increased up to 88.4%~88.8% ISO after PY or YP bleaching. There was no difference in the brightness between PY and YP bleaching. And the dirt count of bleached pulps was similar each other at the range of 17~38 ppm. The tensile index of bleached pulps was slightly higher in PY bleaching than those in YP bleaching. While with the treatment of kneading, the brightness and dirt count decreased remarkably compared to those of no-kneading. However, the sharp difference in the brightnesses or in dirt count of bleached pulps decreased after bleaching. The brightness of bleached pulps at YP stages was only numberically higher than those at PY stages without regard to the treatment of kneading. Therefore, in the case of the neutral deinkiing process, the conversion of PY bleaching stages to YP bleaching stages was profitable to water loop system, and was harmless in the aspect of the bleach efficiency.

• Microbiology and Biotechnology Letters
• /
• v.20 no.5
• /
• pp.527-533
• /
• 1992

The optimal conditions for cellulase and xylanase production by Trichoderma reesei 28217 were studied for enzymatic deinking of old newspaper. The amounts of cellulase and xylanase from the strain was varied by initial medium pH, Tween 80, inoculum size of spore suspension, and carbon and nitrogen sources. The optimal conditions for cellulase production were pH 5.0-6.5, 0.02% of Tween 80, 0.5-1.0% of inoculum size of spore suspension ($1{\times}10^{7}$/ml). cottonseed meal as nitrogen source, and corn flour as carbon source. On the other hand, the optimal conditions for xylanase production were pH 6.5, 0.01% of Tween 80, corn steep liquor as nitrogen source, and disintegrated old newspaper as carbon source. The inoculum size for xylanase production was the same as for cellulase production. The concomitant production of cellulase and xylanase in shake flask culture was efficiently induced in the medium containing 0.5% cottonseed meal as nitrogen source and 1.0% old newspaper and 2.0% corn flour as carbon sources. In this case the activities of cellulase and xylanase produced were 6.11-7.22 IU/mJ and 97.7 IU/ml. respectively. However, the cellulase production in $5{\ell}$ fermentor scale was slightly decreased compared with that in flask scale. Moreover, xylanase production was severely reduced in a fermentor scale. The study for the reason of decreased enzyme production in fermentor is further needed.

• KSBB Journal
• /
• v.11 no.6
• /
• pp.718-725
• /
• 1996

Old newsprint was deinked with endoglucanase, exoglucanase and their various compositions from Trichoderma viride. The yield decreased with an increase in enzyme concentration. Especially, it was the lowest in the treatment of endo-exo mixture(1:1). It may be regarded as a synergistic actions of the cellulase components. The brightness was the highest in pulp deinked with endo-exo mixture(1:1). Maximum brightness was observed when 0.5mg/mL of the endo-exo mixture was used. The physical strength increased with increasing concentration in exoglucanase. But, it decrease with increasing concentration in endoglucanse and endo-exo mixture(1:1). Also, we investigated the yield, brightness and physical strength of endoglucanase in combination with exoclucanase(12:1, 8:1, 4:l, 1:1, 1:4, 1:8, 1:12). Maximal deinking conditions, obtained at a specific optimal ratio of endoglucanase to exoglucanse are as follow ; 12:1 for yield, 12:1 for brightness, 4:1 for tensile strength, 12:1 for bursting strength, and 8:1 for tearing strength. These results indicated that the deinking depended largely upon the action of endoglucanase. Exoglucanase was occupying more than 60% of the total crude cellulase contents. Therefore, the most effective deinking must repress the action of exoglucanase.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2005.04a
• /
• pp.192-196
• /
• 2005

• Resources Recycling
• /
• v.21 no.5
• /
• pp.44-49
• /
• 2012

In this study, the sonication method was applied to remove ink from old newspaper(ONP) using flotation. Results indicated increased whiteness and effective residual ink concentration (ERIC) with longer disintegration. Therefore 58% of whiteness and 182.9 ppm ERIC were obtained for 30 minutes of disintegration time without the change in yield. Longer disintegration than 30 minutes had no effects on whiteness without the application of ultra-sonication. On the other hand, higher than 58% of whiteness was achieved in 2 minutes of disintegration when the ultra-sonication was applied. The highest whiteness (59.32 %) was obtained by applying sonication for 20 minutes and froth flotation with kerosene as a collector under the alkaline condition (pH 11).

• Applied Chemistry for Engineering
• /
• v.7 no.4
• /
• pp.787-793
• /
• 1996

In this paper, to investigate the effect of the offset ink formulation on deinking of Korean old newspaper, the samples printed with five different types of offset ink were aged naturally for 10, 30, 90, 180 days, and then yield, brightness, fiber length, physical properties(tensile, tear, burst index) were evaluated according to aging time. As the aging time increased, the yield and brightness of respective samples decreased. Particially, as the addition amounts of linseed oil increased, those of samples decreased. Therefore, linseed oil is thought to reduce the deinkability of ink. Also, containing rosin-modified phenolic resin and gilsonite seem to reduce brightness of samples according aging time. In physical properties, tensile index and burst index were roughly decreased, but tear index was increased according to aging time. However, the three indexes of the sample containing only linseed oil as the vehicle component were considerably reduced in comparison with those of other samples, as once crosslinked a strong bond between the ink and fibers was produced and made it difficult to defibrate in producing sheets.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.1
• /
• pp.1-7
• /
• 2001

The immediate purposes of this study is to establish the surface chemical principles associated with the flotation process of waste papers and to verify them by practical flotation experiments. To achieve this AKD sized hydrophobic microcrystallince cellulose (MCC) with different levels of hydrophobicity, and hydrophilic MCC dyed with black were prepared as model substances. The effects of surface characteristics on flotation efficiency were evaluated by measuing the brightness of the flotation rejects obtained after the flotation experiments carried out using MCC mixtures prepared with different ratios of hydrophobic and hydrophilic MCCs. Results showed that more than 90% of the flotation rejects consisted of hydrophobic MCC indicating the critical importance of the hydrophobicity of the materials in the flotation process. The proportions of hydrophobic materials in the reject remained constant when highly sized MCC was used as a model of hydrophobic substance.

• Journal of the Korean Wood Science and Technology
• /
• v.21 no.1
• /
• pp.59-64
• /
• 1993

The purpose of this study is to investigate the preparation of the carboxymethylcellulose from recycled fiber, especially on the reactivity of carboxymethylation. Using a deinked pulp and a dissolving pulp. Green's method is adapted to the carboxymethylation. We conformed that the carboxymethyl group is led for recycled fiber by FT-IR analysis. The recycled fiber is more reactive than the dissolving pulp because the recycled fiber had been defiberated and pretreated with alkali. It suggests that deinking process is in accordance with pretreatment of CMC process. Therefore, it may be possible to prepare CMC from the recylced fiber economically.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.36 no.1
• /
• pp.24-29
• /
• 2004

Alkaline cellulolytic enzymes from cultured medium of Coprinus cinereus 2249 were purified with gel and ion-exchange chromatography and characteristics of those enzyme proteins were investigated. A fiber length distribution and a crystallinity of cellulose and sugar composition of enzyme treated Mixed Office Wastepaper(MOW) and Unbleached Kraft Pulp(UKP) were analysed. The conclusion could summarized as follows; \circled1 Alkaline and acidic, endo- and exo-glucanases were purified from cultured medium of Coprinus cinereus 2249. \circled2 The approximate molecular weight of alkaline endo-glucanase was 42 kDa, and also that of alkaline exo-glucanase was 50 kDa. A fiber length distribution and a crystallization of cellulose and sugar composition of enzyme treated MOW and UKP were not so much changed with original paper and pulp.