• Carbon letters
• /
• v.7 no.3
• /
• pp.161-165
• /
• 2006

Activated carbon fiber could be prepared at 973 K by catalytic activation using potassium hydroxide. Phenol resin fiber (Kynol) was impregnated with potassium hydroxide ethanol solution, carbonized and activated at 973 K, resulting in activated carbon fibers with different porosities. The potassium hydroxide accelerated the activation of the fiber catalytically to form narrow micropore preferentially in carbon dioxide atmosphere. The narrow micropore volume of 0.3~0.4 cc/g, total pore volume of 0.3~0.8 cc/g, mean pore width of 0.5~0.7 nm was obtained in the range of 20~50% burnoff.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.2
• /
• pp.218-230
• /
• 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.

• Carbon letters
• /
• v.16 no.4
• /
• pp.275-280
• /
• 2015

• Journal of the Korean Applied Science and Technology
• /
• v.28 no.2
• /
• pp.178-184
• /
• 2011

The analysis of reaction kinetics provided that the reaction order was the $1^{st}$ of triglyceride and the rate constant was 0.067 $min^{-1}$. The transesterification of camelina oil using 0.6 wt% mixed catalyst which consists of 40 v/v% of potassium hydroxide (1 wt%) and 60 v/v% of tetra methyl ammonium hydroxide (0.8 wt%), was carried out at $65^{\circ}C$ on the tubular reactor packed with static mixer. The conversion was shown to be 95.5% at the 6:1 molar ratio of methanol to oil, flow rate of feed of 3.0 mL/min and 24 of element of static mixer. The volume of washing water emitted by 0.6 wt% mixed catalyst was the half of the volume emitted by 1 wt% potassium hydroxide.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.5
• /
• pp.776-778
• /
• 2006

• New & Renewable Energy
• /
• v.5 no.1
• /
• pp.26-31
• /
• 2009

The surface etching characteristics of single crystalline silicon wafer were investigated using potassium hydroxide (KOH) and tetramethylammonium hydroxide (TMAH). The saw damage layer was removed after 10min by KOH 45wt% solution at $80^{\circ}C$. The wafer etched at high temperature ($90^{\circ}C$) and in low concentration (4wt%) of TMAH solution showed an increased etch rate of silicon wafer and wavy patterns on the surface. Especially, pyramidal textures were formed in 4wt% TMAH solution without alcohol additives.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.299.2-299.2
• /
• 2013

We investigated the potassium remaining on a crystalline silicon solar cell after potassium hydroxide (KOH) etching and its effect on the lifetime of the solar cell. KOH etching is generally used to remove the saw damage caused by cutting a Si ingot; it can also be used to etch the rear side of a textured crystalline silicon solar cell before atomic layer-deposited Al2O3 growth. However, the potassium remaining after KOH etching is known to be detrimental to the efficiency of Si solar cells. In this study, we etched a crystalline silicon solar cell in three ways in order to determine the effect of the potassium remnant on the efficiency of Si solar cells. After KOH etching, KOH and tetramethylammonium hydroxide (TMAH) were used to etch the rear side of a crystalline silicon solar cell. To passivate the rear side, an Al2O3 layer was deposited by atomic layer deposition (ALD). After ALD Al2O3 growth on the KOH-etched Si surface, we measured the lifetime of the solar cell by quasi steady-state photoconductance (QSSPC, Sinton WCT-120) to analyze how effectively the Al2O3 layer passivated the interface of the Al2O3 layer and the Si surface. Secondary ion mass spectroscopy (SIMS) was also used to measure how much potassium remained on the surface of the Si wafer and at the interface of the Al2O3 layer and the Si surface after KOH etching and wet cleaning.

• Journal of the Korean Ceramic Society
• /
• v.39 no.7
• /
• pp.699-703
• /
• 2002

In order to see the effect of pH on the formation of ettringite, pH was controlled with addition of boric acid, hydrochloric acid, nitric acid and potassium hydroxide during the formation of ettringite. The behavior of ettringite formation was discussed with XRD, SEM analysis. The result was that ettringite was unstablely formed with stabilization of aluminate gel and gypsum at below PH 10.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.2
• /
• pp.78-90
• /
• 2012

Soybean hull is an attractive feedstock for glucose production. To increase the glucose conversion in acid hydrolysis, a pretreatment method combined steam explosion with alkali pretreatment for soybean hull was studied. For first step pretreatment, steam explosion conditions (log Ro 2.45) were optimized to obtain maximum solid recovery and cellulose content. In the second step pretreatment, the conditions for potassium hydroxide pretreatment of steam exploded soybean hull were optimized by using RSM (response surface methodology). The optimum conditions for minimum lignin content were determined to be 0.6% potassium hydroxide concentration, $70^{\circ}C$ reaction temperature and 198 min reaction time. The predicted lignin content was 2.2% at the optimum conditions. Experimental verification of the optimum conditions gave the lignin content in similar value with the estimated value of the model. Finally, glucose conversion of pretreated soybean hull using acid hydrolysis resulted in $97.1{\pm}0.4%$. This research of two-step pretreatment was a promising method for increasing the glucose conversion in the cellulose-to-glucose process.

• Journal of the Korean Ceramic Society
• /
• v.42 no.4
• /
• pp.282-286
• /
• 2005

Leucite crystal has been utilized for dental porcelain due to its high thermal expansion coefficient to meet its counter metal side. Many industrial applications of leucite from the incongruently melting of potassium feldspar are used and its minimum temperature of crystallization is $1150^{\circ}C$. This study aimed to get leucite crystal from lower temperature through congruently melting, and the starting materials are taken from K-feldspar mainly, and aluminum hydroxide and potassium carbonate are additionally supplied to meet stoichiometry of leucite. We report that the leucite crystal can be synthesized in congruently melting from the temperature $950^{\circ}C$ through solid-state sintering with k-feldspar, potassium carbonate and aluminum hydroxide.