• Journal of the Korea Furniture Society
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• v.10 no.1
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• pp.51-56
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• 1999

This research was carried out to investigate the Hanji sludge(black color)-wood fiber and wood particle composited applied by waste sludges arising from the making process of Hanji (Korea paper). In experimental design, four levels of the mixed ratio of Hanji sludge to wood fiber or wood particle(10:90, 20:80, 30:70 and 40:60), three kinds of the resin(PMDI, urea and phenol resin)and three kinds of the specific gravity(0.6, 0.75 and 0.9) were designed to determine the tensile strength of Hanji sludge-wood fiber and wood particle composites. From the results and discussion, it may be concluded as follows: In Hanji sludge-wood fiber and wood particle composites, tensile strengths showed decreasing tendency absolutely by increasing Hanji sludge additive, but clearly increase with the increase of specific gravity. In Hanji sludge-wood fiber composites, there were no differences between PMDI and urea resin-bonded composites, but phenol resin-boned composites were made possibly until the addition of 30% Hanji sludge. On the other hand, Hnji sludge-wood particle composites(SpGr=0.6) have very low tensile strength values. But they were made favorably until the addition of 20% Hanji sludge in Hanji sludge-wood particle composites(SpGr=0.9).

• Journal of the Korean Wood Science and Technology
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• v.29 no.2
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• pp.109-117
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• 2001

This research was carried out to develop the Hanji(Korean paper) sludge wood particle composite utilizing the waste sludges occurring from the making process of Hanji(Korean paper). In the research, four mixing ratios of white or black sludge to wood particle(10:90, 20:80, 30:70, and 40:60), three types of the resin adhesives(PMDI, urea and phenol resin) and three levels of the densities(0.60, 0.75 and 0.90) were designed to investigate the physical properties of Hanji(Korean paper) sludge wood particle composite. The linear expansion of Hanji(Korean paper) sludge wood particle composite was not always increased, compared to control boards. For thickness swelling, PMDI-bonded composites had the lowest value, and thickness swelling of composite was generally decreased with the increase of Hanji sludge. The water absorption of white sludge wood particle composite had no tendency, hut that of black sludge wood particle composite was decreased with an increase of mixing ratio of Hanji sludge.

• Analytical Science and Technology
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• v.15 no.2
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• pp.157-162
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• 2002

A technique which could collect the traditional and the industrial hanji fibrous sludge efficiently from wastewater using a cationic surfactant cetyltrimethylammonium chloride (CTAC) was developed. When the concentration of CTAC was $1{\mu}g/mL$ in wastewater that the amount of the traditional hanji fibrous sludge was about 0.08 g/L, the collecting yield was more than 95% and the collecting time was less than 30 sec. When only CTAC was used to collect the industrial hanji fibrous sludge, about 90% of collecting yield was obtained at more than $15{\mu}g/mL$ CTAC. But the sludge layer at the surface of solution was not stabilized and the flotation time was relatively longer. And, when $5{\mu}g/mL$ CTAC and various amount of PAMID$^{(R)}$ was added to the industrial hanji sludge, the collecting yield was increased and sludge layer also was more stabilized. But the collecting yield was higher in the traditional hanji sludge than in the industrial hanji sludge.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.121-127
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• 2002

This research was carried out to develop the Hanji(Korean paper) sludge·wood particle composite utilizing the waste sludges occurring from the making process of Hanji(Korean paper). At the research, four mixing ratios of white or black sludge to wood particle(10:90, 20:80, 30:70 and 40:60), three types of the resin adhesives(PMDI, urea and phenol resin) and three levels of the densities(0.60, 0.75 and 0.90) were designed to investigate the mechanical properties of Hanji(Korean paper) sludge·wood particle composite. In the white and black sludge·wood particle composites, bending properties(MOR, MOE) showed the decreasing tendency according to the increase of sludge additive, but it was clearly increased with the increase of specific gravity. Also tensile strength had the same tendency as in these bending properties. The internal bond strength of white sludge·wood particle composite had no tendency, but that of black sludge·wood particle composite was decreased as an increase of Hanji sludge additive.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.31-37
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• 1999

This study was carried out to develop the Korean paper(Hanji) sludge-wood fiber composite boards utilizing the relinquished sludges occurring from the making process of Korean classic paper Hanji. The bark of paper mulberry(Broussonetia kazinoki Sieb.) has been used as a raw material since past hundreds and thousands years. Korean paper(Hanji) sludge was divided into two kinds, the one was the white sludge from the first stage and the other was the black sludge occurring from the final stage of Korean paper(Hanji) making. Four levels of the mixed ratio of each white or black sludge to wood fiber(10:90, 20:80, 30:70 and 40:60), three levels of the resin adhesives(PMDI, urea and phenol resin) and three levels of the density(0.60, 0.75 and 0.90) were designed to investigate the mechanical properties of Korean paper(Hanji) sludge-wood fiber composite boards. From the results and discussion, it could be concluded as follows : 1. In the white and black sludge-wood fiber composite boards, bending modulus of rupture showed the clear decreasing tendency according to the increase of sludge additive, but it was clearly increased with the increase of specific gravity. Modulus of elasticity showed the same tendency as in the modulus of rupture, and also tensile and internal bonding strength had the same tendencies as in these bending properties. 2. Among the resin adhesives, PMDI or urea resin showed great values in MOR of white sludge-wood fiber composite board, but urea resin was greater than PMDI in MOR and MOE of black sludge-wood fiber composite board. Tensile and internal bonding strength showed the same tendencies as in white sludge-wood fiber composite board. 3. It is suggested that the white sludge-wood fiber composite boards bonded with PMDI or black sludge-wood fiber composite boards bonded with urea resin were able to made similar boards to general fiberboard by the mixed ratio 20:80 of sludge to wood fiber.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.23-30
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• 1999

This study was carried out to develop the Korean paper(Hanji) sludge-wood fiber composite boards utilizing the relinquished sludges occurring from the making process of Korean classic paper Hanji. The bark of paper mulberry(Broussonetia kazinoki Sieb.) has been used as a raw material since past hundreds and thousands years. Korean paper(Hanji) sludge was divided into two kinds, the one was the white sludge from the first stage and the other was the black sludge occurring from the final stage of Korean paper(Hanji) making. Four levels of the mixed ratio of each white or black sludge to wood fiber(10:90, 20:80, 30:70 and 40:60), three levels of the resin adhesives(PMDI, urea and phenol resin) and three levels of the density(0.60, 0.75 and 0.90) were designed to investigate the physical properties of Korean paper(Hanji) sludge-wood fiber composite boards. From the results and discussion, it could be concluded as follows : 1. In the white sludge-wood fiber composite board, the thickness swelling was not affected by the specific gravity and sludge additive of composite boards, but among the resin adhesives PMDI resin showed the best dimensional stability. Water absorption was superior in urea resin, secondly PMDI resin and very poor in phenol resin. 2. In the black sludge-wood fiber composite board, thickness swelling was superior in PMDI resin but very poor in phenol resin. In water absorption, PMDI and urea resin showed good results, regardless of specific gravity or sludge additive, but phenol resin showed poor results. 3. From the results and discussion of physical properties it is suggested that the white sludge-wood fiber composite boards bonded with PMDI or black sludge-wood fiber composite boards bonded with urea resin were made possibly with similar or better properties. compared with general fiberboard until the addition of 20% sludge into wood fiber.

• Analytical Science and Technology
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• v.14 no.2
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• pp.167-172
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• 2001

The technique that could collect efficiently the hanji fibrous sludge from wastewater using surfactants was developed. When fibrous sludge of which concentration was about 80mg/L, was floated and collected, the optimum concentration of sodium oleate, the pore size of glass filter and the air flow rate were 10mg/L, $5-10{\mu}m$ and 200mL/min., respectively. The behavior of sodium oleate might be interfered by polyvalent cations such as $Ca^{2+}$. But when the concentration of $Ca^{2+}$ was less than 100mg/L, the interference effect did not appear. And when a typical cationic surfactant, cetyltrimethylammonium bromide(CTAB), was used, the collecting yield was less than that of sodium oleate, and the amount of foam was higher than sodium oleate. When 1mg/L of CTAB was added to the hanji sludge sample contained 1mg/L of $PAMID^{(R)}$, a dispersant, fibrous sludge was effectively coagulated, the flotation time was very short and the collecting yield was above 95%. But in the case, sodium oleate was inefficient.

• Analytical Science and Technology
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• v.12 no.4
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• pp.318-325
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• 1999

Sludges from the wastewater of hanji production were analysed to see that sludges from the bleaching process, the bleach washing process, and the paper preparation process were fibrous, while sludges from the process cooking with NaOH and the process of final chemical and microbiological treatment were non-fibrous. Sludge solution from the bleaching process had the most amount of solid matters. Sludges from the bleaching process, the bleach washing process, and the final chemical and microbiological treatment process contained about 80-90 %(w/w) moisture. Owing to hypochlorite ion, pH of sludge from the bleaching process was higher than any other sludge samples. The inorganic components of sludges were determined by ICP-AES. The major inorganic component of sludge from the process cooking with NaOH was Na, while the sludge from the bleaching process had Na and Ca, major components in the final chemical and microbiological treatment process were Ca and Al. Trace amount of Mg, Fe, K, P, Mn and Ti were observed in sludges. Sludge from the bleaching process had ashes more than any other sludges. Shape of sludges observed by SEM was appeared to fibrous or crystalline, and the breadth of fibrous sludge was $5{\sim}50{\mu}m$. The sludge from the bleaching process had the most amount of matters soluble by cold and hot water and by alcohol-benzene.

• Analytical Science and Technology
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• v.13 no.3
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• pp.351-356
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• 2000

The decolorization of wastewater and the collecting conditions of final sludge from hanji production were investigated. Black wastewater (50 mL) from the process cooking with NaOH could be effectively decolorized by 2.0 g of $Ca(OCl)_2$ So, if excess bleach $Ca(OCl)_2$ used in bleaching process were recycled, the decolorization of wastewater by adding less $Ca(OCl)_2$ would be successfully realized. However, the decolorization by electrolyzed oxidation was ineffective. The final sludge could be effectively collected by polymer coagulator, but the addition of $Al_2(SO_4)_3$ was required, and the pure fibrous sludge could not be collected. Therefore, surfactants such as triethanolamine and Triton X-100 were used instead of polymer coagulator. The collecting yield was obtained about 85% as good as those by polymer coagulator. When mixed surfactants were used in collecting the final sludge, $Al_2(SO_4)_3$ was not required. In addition, as the pure fibrous sludge could be collected, the effective recycling of sludges would be done.