• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.218-230
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• 2016

The effect of steam explosion coupled with alkali (1% sodium hydroxide, 1% potassium hydroxide and 15% sodium carbonate) or organosolv solvent (85% methanol, 70% ethanol and dioxane) on the production of sugar, changes in the chemical composition of M. sinensis were evaluated. The steam explosion coupled with 1% potassium hydroxide and dioxane were better as compared with other treatments based on the removals of acid insoluble lignin, and about 89.0% and 85.4%. Enzymatic hydrolysis of steam explosion with 1% potassium hydroxide and dioxane treated M. sinensis, gave a 98.0% and 96.5% of glucose conversion, respectively. These results suggested that pretreatment of M. sinensis with either potassium hydroxide or dioxane could be a promising pretreatment method for glucose production.

• Journal of the Korean Wood Science and Technology
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• 제20권3호
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• pp.11-20
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• 1992

Steam explosion is one of the most effective pretreatment for fractionating wood. This leads to the total utilization of wood basic components; cellulose, hemicellulose and lignin. The amount of sugar and lignin extracted with the hot water method was very low. The lignin content of residues after extraction with using a sodium hydroxide treatment, increased delignification of carbohydrate as the concentration of alkali was increased. Oak, pretreated with steam exploded at 25kg/$cm^2$ for 6 min. then 1% alkali for 2hrs. showed a delignification rate up to 95%. A sodium chlorite treatment of steam exploded pine and oak also afforded a high deligninfication effect. Pine, treated 10% sodium chlorite for 2hrs. showed high delignification. However, by using a sodium hydroxide treatment, a 2% retreatment for Ihr. after a 2% for 2hrs. afforded remarkable delignification effect on exploded wood at 30kg/$cm^2$ for 9min. and at 35kg/$cm^2$ for 3-6min. In oak, an initial 2hrs. treatment of 2% sodium chlorite was followed by a second 2hrs. treatment at 10%. This showed a delignification rate of 96%.

• 한국염색가공학회지
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• 제8권2호
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• pp.35-42
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• 1996

Peroxodisulfates are being developed as low temperature bleaching agents for cotton fabrics to save the thermal energy. In this research we used the colar difference meter to determine the whiteness which peroxide booster will possibly make an effect on cotton fabric at the low temperature process using consist of temperature with different conditions agents, such as sodium hydroxide, sodium peroxodisulfate and potassium peroxodisulfate. The peroxide bleaching follows a laboratory experiments, using a statistical plan for three variables: the concentrations of hydrogen peroxide and sodium hydroxide and the temperature of bathing. The purpose of this research was to use the response surface analysis method to evaluate the relative importance of factors providing optimum whiteness. A ridge analysis of the data on whiteness response results in 3-D response surface diagrams for optimizing the concentrations of hydrogen peroxide and sodium hydroxide at about 42~52$^{\circ}C$.

• 한국세라믹학회지
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• 제18권2호
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• pp.91-98
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• 1981

Synthetic zeolite A was prerared from domestic Hadong kaolin with sodium hydroxide solution and their ion exchange isotherms of $K^+$, $NH^{4+}$, $Li^+$ and $Ag^+$ ion were presented. The optimum reaction conditions for synthetic zeolite A from calcinated kaolin were 2 fold excess of 2N sodium hydroxide solution, 10$0^{\circ}C$ and 8 hours. It was observed that before the crystallization of zeolite A the samples reacted with sodium hydroxide solution had rather higher ion exchange capacities than zeolite A. The $K^+$-$Na^+$ and $Ag^+$$Na^+$ ion exchange isotherms were signoidal. The initial selectivity series was in the order $Ag^+$$K^+$>$Na^+$>$NH_4$>$Li^+$. Between approximately 33 and 67% replacement of soium ions the selectivity series became $Na^>$ and above 67% became $Ag^+$>$K^+$. Evidence were also presented to demonstrate that 8 out of 12 sodium ions per pseudo unit cell were not easily replaceable by lithium ions and 4 out of 12 not easily replaceable by ammonium ions.

• 월간산업보건
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• 통권353호
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• pp.29-33
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• 2017

수산화나트륨(Sodium hydroxide)의 직업적 노출에 대한 TLV-Ceiling은 $2mg/m^3$으로 권고하였다. 권고수준은 수산화나트륨 에어로졸이 눈, 점막, 피부에 심한 자극을 유발하고 수산화나트륨 분진이 상기도 기관에 자극을 유발하는 농도에 근거하였다. 노출기준은 눈과 상기도 기관에 자극을 최소화하기 위하여 권고하였다. 고농도의 수산화나트륨에 장기간 노출되면 비강 궤양과 눈과 피부에 심한 손상을 유발할 수 있다. "피부", "감작제(SEN)", "발암성"의 경고주석을 권고하기에는 유용한 자료가 충분하지 않다.

• 한국방재학회 논문집
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• 제9권1호
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• pp.73-79
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• 2009

유해물질은 만일 누출된다면 화재 폭발 독성 및 위해성이 있는 물질을 말한다. 많은 선진국에서 유해물질의 수송이 증가하고 있기 때문에 유해물질의 생산 저장 수송 사용 및 폐기에 대한 정확한 정보는 매우 중요하다. 유해물질의 수송은 유해물질의 사용과정에서 핵심적인 기능이라고 말할 수 있다. 정부는 유해물질에 대해 많은 법령과 규제, 기준들을 개발해 왔다. 그러나 한국의 법령, 규제, 기준들은 비록 유해물질의 이동이 유해물질 수송에 대한 안전과 방재차원에서 중요한 정보임에도 불구하고, 유해물질의 O-D수송에 대한 정확한 정보를 보장하고 있지 못한 실정이다. 본 연구의 목적은 한국의 유해물질 수송에 대해 새롭게 대두되거나 기존에 제기된 이슈들을 조사하고, 제한된 자료를 가진 상황에서 유해물질에 대한 O-D매트릭스를 예측하는 기법을 개발하는 것이다. 본 연구는 유해물질 수송사례에 대한 40개의 후보군 중에서 수산화나트륨 폐기물에 대한 수송이 사례 연구로 선정하였다. 성장률법이 수산화나트륨 폐기물 수송의 2005년 O-D매트릭스를 추정하는데 적용되었다. 행렬보정기법이 추정된 수산화나트륨 O-D매트릭스를 보정하는데 사용되었다. 본 연구는 유해물질에 대한 O-D추정기법의 적용가능성을 제시하였다. 본 연구를 통해 도출된 수산화나트륨 폐기물 O-D 매트릭스는 수산화나트륨 수송의 수송로와 수송구간을 추적하는데 사용되어 진다.

• 한국세라믹학회지
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• 제15권1호
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• pp.21-27
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• 1978

Hadong Kaolin (Halloysite) was granulated cylindrically and treated with 1N aqueous sodium hydroxide solution for 6-48 hrs at 60-10$0^{\circ}C$. The crystalling structure of surface of the products was studied by X-ray powder diffraction method. The reaction rate of halloysite to sodium A zeolite showed a gradual decrease from surface to inner layer. At the surface layer, the reaction mechanism was observed as first order consecutive reaction as follows: halloysitelongrightarrowamorphous aluminosilicatelongrightarrowsodium A zeolitelongrightarrowhydroxysodalite By applying the above reaction mechanism, the rate constants and activation energies was measured.

• 펄프종이기술
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• 제43권3호
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• pp.106-112
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• 2011

The effects of alkaline treatment on the WRV, crystalline structure and sheet structure of softwood and hardwood bleached kraft pulp were investigated. Sodium hydroxide and sodium carbonate were used as chemicals for alkaline treatment and two levels of alkali dosage (5%, 10%) were applied respectively. Alkali treated and untreated pulp were refined to three levels (550, 450 and 350 mL CSF). WRV of the alkali treated pulps depended on the alkaline type and concentration. It was found that the crystalline structures of softwood and hardwood pulp were not changed by refining. Sodium carbonate and lower concentration of sodium hydroxide treatment did not caused any modification of cellulose crystalline structure, while higher concentration of sodium hydroxide treatment caused the partial modification of cellulose crystalline structure. Alkaline treatment of hardwood bleached kraft pulp led to the shrinkage of fiber diameter and bulky structure of sheet. Alkaline treatment of softwood bleached kraft pulp did not cause the significant change in fiber shrinkage and bulk of sheet.

• 한국환경보건학회지
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• 제18권2호
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• pp.52-56
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• 1992

The ability of chemicals, 10% sodium hypochlorite, 28% ammonium hydroxide, 5% sodium hydroxide, 5% sodium bicarbonate, 0.1% hydrochloric acid, 5% hydrogen peroxide, and 5% acetone, to destroy aflatoxins in laboratory waste water containing 3.26 ppb of B$_{1}$ 7.64 ppb of B$_{6}$3 ppb of G$_{1}$, and 11.39 ppb of G$_{2}$ with the total of 29.11 ppb was investigated. High performance liquid chromatograph (HPLC) was used for the separation and quantitation of aflatoxins. Treatment for 2 hours by the chemicals affected the destruction of aflatoxins and the most effective chemical was 10% sodium hypochlorite (p<0.05). Sodium hypochlorite concentrations more than 1% significantly reduced aflatoxin B$_{2}$, G$_{1}$, G$_{2}$ and total aflatoxins and more than 3% reduced B$_{1}$ (p<0.05). No further significant decreases were observed above the concentration of 5% for all 4 aflatoxins. Complete destruction of aflatoxins B$_{2}$, G_{1}$, and G$_{2}$ was achieved by 5% sodium hypochlorite at 48 hours and B$_{1}$ at 72 hours.

• 펄프종이기술
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• 제46권3호
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• pp.44-49
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• 2014

The mushroom cultured waste(MCW) from cork oak was evaluated as the raw material for bioethanol production. For enzymatic hydrolysis, cellulase cocktails (Celluclast 1.5L and Novozym 188) was used for polysaccharides to monosaccharides conversion. Compared with sound cork oak woodmeal, woodmeal from MCW showed higher cellulose to glucose conversion. To improve polysaccharides to monosaccharides conversion, pretreatment by sodium hydroxide was applied. Even though more xylan and lignin were removed in woodmeal of MCW than that of cork oak, concentration of glucose was higher from sodium hydroxide treated cork oak woodmeal (51.3 g/L) than treated MCW woodmeal (41.6 g/L).