• Proceedings of the Korean Fiber Society Conference
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• 1990.06b
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• pp.34-34
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• 1990

• Journal of the Korean GEO-environmental Society
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• v.8 no.4
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• pp.41-45
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• 2007

It is very important that selection of packing media with large surface area, high limited back pressure in biofilter. The object of this study is the isolation of sulfur-oxidizing bacteria and the removal of hydrogen sulfide in biofilter by media. This investigation led to the following results: 1) we isolated Thiobacillus sp. IW. at an abandoned coal mine in Hwasun, Jeonnam Province. 2) The inorganic media showed better results than the organic media from experiments looking at removal characteristics and changes in pressure drop using various media. 3) Among the inorganic media, fibril and PU media showed best performance.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.523-528
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• 2015

In this study, we investigated the effects of sulfuric acid on the synthesis of calcium borate in the artificial boron-containing brine (bittern) saturated with calcium hydroxide. For the study, we attempted to synthesize calcium borate under various conditions such as reaction temperature, reaction time, and cooling temperature after heating, and then to examine the recovery and purity of the calcium borate according to the presence or absence of sulfuric acid at each condition. The XRD analysis confirmed that, regardless of the presence of sulfuric acid, the calcium borate ($Ca_2B_2O_5{\cdot}H_2O$) was synthesized, while, in the presence of sulfuric acid, the calcium sulfate ($CaSO_4{\cdot}0.5H_2O$) was produced as a by-product. In all the experiments performed by varying the reaction temperature and time, the recovery and purity of the calcium borate without sulfuric acid were observed higher than those with it. The results indicated that the addition of sulfuric acid increased the solubility of the calcium hydroxide, but the calcium sulfate produced as a by-product could decrease the recovery and purity of the calcium borate by preventing the synthesis. In this study, the artificial boron-containing brine (bittern) (500 mg-B/L) was saturated with calcium hydroxide in the absence of sulfuric acid, and then the solution was heated at $80-105^{\circ}C$ for less than 10 minutes to synthesize the calcium borate. The recovery and purity of calcium borate were measured as high as 80 % and 96 %, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.3
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• pp.5-14
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• 2020

This study aims to survey the effect of sulphuric acid (H₂SO₄) treatment for pH adjustment with 6.5 and 7.0 regarding ammonia volatilization on chemical content change in the aerobic liquefying process of co-digesate swine manure and apple pomace. The digestates of swine manure was aerated with 0.3 ㎥ air/㎥·min for 60 days. The untreated digestate showed the increased pH and decreased contents of electrical conductivity (EC) and total nitrogen (T-N). The untreated digestate had a high concentration of NH₃ with 172.6 mg/L, but, ammonia (NH₃) concentration of H₂SO₄-treated digestate was significantly lower than that of untreated digestate. The H₂SO₄-untreated digestate for retaining aeration showed a decreased concentration of 47.2% of ammonium nitrogen. While, the H₂SO₄-treated digestate had a high concentration of ammonium nitrogen compared to the untreated digestate. Also, the H₂SO₄ treatment affected to increase the contents of nitrogen and phosphoric acid content. Therefore, the pH adjustment with H₂SO₄ might be a useful method for the decreased ammonia concentration and nitrogen maintenance in the aerobic liquefying process of swine manure digesate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7433-7438
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• 2015

Deactivation characteristics of $V_2O_5/TiO_2$ catalysts were studied for selective catalytic reduction(SCR) of NOx with ammonia in the presence of $SO_2$. Performance of catalyst was investigated for $deNO_x$ activity while changing temperature, $SO_2$ concentration. The activity of catalyst was decreased with the increase of $SO_2$ concentration and reaction time. Also, degree of activity drop was largely decreased with the increase of reaction temperature in the range of $250{\sim}300^{\circ}C$. Physicochemical properties of deactivated catalysts were characterized by BET, XRD, SEM, TPD analysis. According to the analysis results, deactivation phenomena occur due to the relatively high formation of ammonium sulfate salts, which created by unreacted ammonia and water in the presence of $SO_2$. It was revealed that ammonium sulfate cause the pore plogging of support and deposition of active matter.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.9-17
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• 2008

The presence of thiosulfate oxidizing bacteria was examined in rhizosphere soils of 19 economically important plant species belonging to 10 different families. The results showed that the thiosulfate oxidizing bacteria were present in all the tested rhizosphere soils, and the total 32 thiosulfate oxidizing bacteria were recovered. Furthermore, the biochemical characterization revealed that 56% and 44% of the isolates belonged to the obligate chemolithoautotrophs and facultative heterotrophs, respectively. The isolates ATSR15P utilized 19.17 mM of thiosulfate and accumulated 11.65 mM of sulfate in the medium. Concurrently, the decrease in pH of the medium was observed. This study comprehensively demonstrates that the active sulfur oxidation is a ubiquitous phenomenon in the rhizosphere of crop plants in Korea.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.641-649
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• 2015

The purpose of this study was to assess the durability of high-strength concrete with high volume mineral admixture (HVMAC) derived from previous studies within ternary blended concrete (TBC) and normal concrete (NC). Four durability evaluation types such as chloride penetration resistance, freezing and thawing resistance, carbonation resistance in two pre-treatment conditions, and sulfuric acid and sulfate resistance using 5% sulfuric acid ($H_2SO_4$), 10% sodium sulfate ($Na_2SO_4$), and 10% magnesium sulfate ($MgSO_4$) solution were selected and performed in this study. HVMAC showed the excellent chloride penetration resistance in any age and the freezing and thawing durability close to 100%. In addition, HVMAC affected more reduction in carbonation resistance than TBC. When the curing time was increased, to create a concrete internal organization densely improved resistance to carbonation. HVMAC also showed the most superior in sulfuric acid and sulfate resistance. As the reduction of calcium hydroxide and $C_3A$ to apply a large amount of admixture reduced the swelling and cracking of concrete, the strength reduction and mass change of concrete was found to be small indicated.

• Journal of Energy Engineering
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• v.1 no.1
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• pp.135-151
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• 1992

석탄은 중요한 대체 에너지원 중의 하나이다. 그러나 석탄의 이용은 심각한 환경오염문제를 유발한다. 석탄의 연소와 관련된 환경 오염의 주 원인중의 하나는 석탄의 황 함유로부터 기인한다. 석탄의 연소과정에서 발생되는 아황산 가스는 대기오염과 산성비로 인한 토양오염의 주범중의 하나이다. (중략)

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.444-449
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• 2010

In this study, the petroleum sulfonate(PS) was synthesized from pyolyzed fuel oil by sulfonation reaction with sulfuric acid. The PS synthesized had surfactant behaviors relating to the interfacial properties such as surface tension, surface adsorption, and wetting, etc. These interfacial properties were affected by the sulfonation ratio in the synthesis. As the sulfonation ratio increased, the surface tension of the PS aqueous solution decreased. However, when the ratio was too high, the surface tension was increased due to the extremely higher value of hydrophilicity of PS. At the optimum sulfonation ratio, the PS had a good wettability on the cement particles and a good fluidity of the cement mortar with a high adsorption.

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.156-163
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• 1995

In the previous study, styrene mdleic dnhydride copolymer(SMA) as synthesized flom styrene and rnale~c dnhydr~de and further redcted with sulfuric acid to obtam water soluble SMA. In thls study, the flow dnd strcngth tests of cement mortar rmxed wth copolymers wele carried out to evaluate the capability of copolymers as high range water reducer for the con crete. It was found from flow exper~ment that the fluidity of cenient mortar rmxed wth sulfonated SMA(SSMAj was larger thdn that mxed ulth amnophenol substituted SSMA (SmSMAj. The decreasing rate of the flow of cement mortar rmxed ulth SSMA and SmSMA was significantly lower than that mixed ulth naphthalene condensate(NSC) The compressslve strength of the hardened cement mortars containing 0.5% copolymers after 28 dys curing was exarmned. 'The compressive strength of hdrdened cement mortar containing SSMA and SmSMA was mcreased up to 31% and 13%, respectively, when omp pared to the plain. As the results, the copolyniers(SSMA and SrnSMA) used in thls study are greatly expected as a good high range water reducers for the concrete.