• Title/Summary/Keyword: sulfate ion

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Long-Term Durability Estimation of Cementless Concrete Based on Alkali Activated Slag (알칼리 활성 슬래그 기반 무시멘트 콘크리트의 장기 내구성 평가)

  • Lee, Hyun-Jin;Lee, Seok-Jin;Bae, Su-Ho;Kwon, Soon-Oh;Lee, Kwang-Myong;Jung, Sang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.2
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    • pp.149-156
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    • 2016
  • It has been well known that concrete structures exposed to chloride and sulfate attack environments lead to significant deterioration in their durability due to chloride ion and sulfate ion attack. The purpose of this experimental research is to evaluate the long-term durability against chloride ion and sulfate attack of the alkali activated cementless concrete replacing the cement with ground granulated blast furnace slag. For this purpose, the cementless concrete specimens were made for water-binder ratios of 40%, 45%, and 50%, respectively and then this specimens were cured in the water of $20{\pm}3^{\circ}C$ and immersed in fresh water, 10% sodium sulfate solution for 28, 91, 182, and 365 days, respectively. To evaluate the long-term durability to chloride ion and sulfate attack for the cementless concrete specimens, the diffusion coefficient for chloride ion and compressive strength ratio, mass change ratio, and length change ratio were measured according to the NT BUILD 492 and JSTM C 7401, respectively. It was observed from the test results that the resistance against chloride ion and sulfate attack of the cemetntless concrete were comparatively largely increased than those of OPC concrete irrespective of water-binder ratio.

Diffusion Characteristics for Chloride Ion of Concrete Subjected to Sulfate Attack (황산염 침투를 받은 콘크리트의 염소이온 확산특성)

  • Park, Jae-Im;Bae, Su-Ho;Yu, Jae-Won;Lee, Kwang-Myong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.213-214
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    • 2010
  • An objective of this experimental research is to investigate the diffusion characteristics for chloride ion of concrete subjected to sulfate attack. For this purpose, concretes with three types of cement such as ordinary portland cement(OPC), binary blended cement(BBC), and ternary blended cement(TBC) containing mineral admixtures were made for water-binder ratios of 32% and 43%. The concrete specimens were immersed in sulfate solution for 365 days, and then the resistance against chloride ion penetration of them were estimated by using NT BUILD 492. It was observed from the test results that the resistance to chloride ion penetration of concrete subjected to sulfate attack was greatly decreased than that of standard curing concrete under the same age.

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Flocculation Kinetics Using Fe(III) Coagulant in Advanced Water Treatment: The Effect of Sulfate Ion (상수처리시 Fe(III) 응집제를 이용한 응집동력학에 관한 연구 : 황산이온의 영향)

  • 강임석;이병헌
    • Journal of Environmental Science International
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    • v.4 no.4
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    • pp.367-377
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    • 1995
  • The study of flocculation kinetics is of fundamental interest in the field of water treatment, because rational study of the factors affecting the coagulation process should be based on the rate of particle growth. The effect of sulfate on flocculation kinetics were examined using ferric nitrate as a coagulant to coagulate kaolin clay in water under several experimental conditions. Both the particle size distribution data obtained from the AIA and the on-line measurement of turbidity fluctuation by the PDA were used to measure flocculation kinetics. Results show that sulfate ion added to the kaolin suspension played an important role in the flocculation process, not only improving flocculation kinetics at more acidic pH levels but also changing surface charge of particles. The kinetics of flocculation were improved mainly by the enhanced rate and extent of Fe(III) precipitation attributed to the addition of sulfate, and thereby, better interparticle collision frequency, but little by the charge reductions resulting from the sulfate addition. The increase in sulfate concentration beyond $3\times10^{-4}M (up to 2\times10^{-3}M)$ did not induce further improvement in flocculation kinetics, although the higher concentrations of sulfate ion substantially increased the negative ZP value of particles. Key Words : Flocculation Kinetics, Fe(III) Coagulant, Sulfate ion, Turbidity Fluctuation.

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Online preconcentration and preelutioin for the ion chromatographic determination of trace anions in high-sulfate wastewater

  • Song, Kyung-Sun;Kim, Sang-Yeon;Cheong, Young-Wook
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2005.05a
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    • pp.327-328
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    • 2005
  • Trace anions in high-sulfate wastewater from mainly derelict mines were determined by ion chromatography with on-line preconcentration and preelution technique. As the sample was preconcentrated and more strongly held ions were preeluted to the principal separation system, this approach was highly effective in removing large concentration of sulfate in high-sulfate wastewater. With this practical on-line preelution treatment, the peaks of fluoride and chloride showed good resolution even when the sulfate concentration was as high as 2000 mg/L and the analyzed total metal concentration was above 500 mg/L.

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Characterization of Synthetic Polymeric AI(III) Inorganic Coagulants for Water Treatment (상수처리용 합성 무기고분자 Al(III)계 응집제의 화학적특성)

  • Han Seung-Woo;Jung Chul-Woo;Kang Lim-Seok
    • Journal of Environmental Science International
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    • v.8 no.6
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    • pp.711-716
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    • 1999
  • This research explored the feasibility of preparing and utilizing a prefonned polymeric solution of Al(III) for coagulation in water treatment. Slow base(NaOH) injection into supersaturated aluminum chloride and aluminum sulfate solutions did produce high yields of Al polymers useful to water treatment applications. The method of characterization analysis was based on timed spectrophotometer with ferron as a color developing reagent. The hydrolytic Al species were divided into $monomeric(Al_a),\;polymeric(Al_b),\;and\;precipitate(Al_c)$ from the difference in reaction kinetics. The analysis of PACl's characteristics showed that the quantity of polymeric Al produced at value of$ r(OH_{added}/AI)=2.2$ was $83\%$ of the total aluminum in solution, as showing maximum contents and precipitated Al was dramatically increased when r was increased above 2.35. In addition, the characteristics of polyaluminum sulfate (PAS) showed that polymeric Al contained at r = 0.75 was $18\%$ of the total aluminum in solution. The synthesized PACI and PAS were stable during storing period, as indicating negligible aging effect. The effect of sulfate ion on PACI was dependent on the concentration of sulfate ion. That is, polymeric species decrease and precipitate species increase as sulfate ion concentration increased. It can be concluded that the sulfate cause the formation of $Al(OH)_{3(S)}$ at low pH. However, The effect of calcium ion was negligible for distribution of Al species.

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An Experimental Study on the Ion Reaction and the Electrochemical Rebar-Corrosion in Aqueous Solution Mixed with Sulfate and Chloride Ion-Reactive Material (황산, 염소이온 반응 소재 혼입 수용액에서의 이온반응성 및 전기화학적 철근 부식에 관한 실험적 연구)

  • Ryu, Hwa-Sung;Shin, Sang-Heon;Kang, Tae-Won;Lim, Chang-Gil;Kim, Hong-Tae
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.1
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    • pp.31-38
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    • 2019
  • In this study, amine derivatives and ion exchange resins were selected to actively control penetration ions ($SO{_4}^{2-}$, $Cl^-$) as the element technology of repair materials for concrete structures in drainage environments. Ions ($SO{_4}^{2-}$, $Cl^-$) adsorption performance and corrosion resistance of calcium hydroxide solution with amine derivative and ion exchange resin were confirmed by ion chromatography and potentiostat analysis. As a result of the experiment, it was confirmed that the amine derivative is excellent in the adsorption of chlorine ion and the ion exchange resin is excellent in the adsorption of sulfate ion. It has been confirmed that corrosion resistance can be increased by proper combination of two materials in the calcium hydroxide solution containing sulfate ion and chloride ion simulating sewage environment.

Sanitary Chemical Conditions of Farmwaters in Choongcheongnam and Kangwon Province According to Spring and Summer (충청남도 및 강원도 목장지역 목장용수의 춘하절간 위생화학적 변화)

  • 이강문;박석기;이용욱
    • Journal of Food Hygiene and Safety
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    • v.9 no.4
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    • pp.229-235
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    • 1994
  • It is very important to investigate the sanitary chemical conditions of farmwaters used for cattle breeding in the dairy farms. For this purpose we examined pH, KMnO4 consumption, total hardness, chloride, sulfate, NH3-N, NO3-N, fluoride, lead, iron, manganese, cadmium, copper, zinc and chrome in the farmwaters sampled 2 times(spring and summer)in Choongcheongnam and Kangwon Province. The pH of farmwaters in Choongcheongnam and Kangwon Province was 6.49$\pm$0.09, 6.70$\pm$0.06, total hardness 90.21$\pm$7.07, 64.53$\pm$6.38 mg/ι, consumption of KMnO4 4.13$\pm$0.62, 4.34$\pm$0.26mg/ι, NO3-N 6.51$\pm$0.55, 3.61$\pm$0.58 mg/ι, chloride ion 20.51$\pm$1.99, 5.41$\pm$1.36 mg/ι and sulfate ion 6.61$\pm$1.02, 7.28$\pm$1.30 mg/ι, respectively. But NH3-N was scarcely detected. Fluoride, iron, lead, cadmium, zinc, manganese and chrome were not detected from the tested farmwaters. There was high significance between each other in total hardness, NO3-N, chloride ion and sulfate ion. There was regional and seasonal significance in only NO3-N but only regional significance in total hardness and chloride ion.

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A Microscopic Study on Treatment Mechanism of Acid Mine Drainage by Porous Zeolite-slag Ceramics Packed in a Column Reactor System (컬럼반응조 내 충진된 다공성 zeolite-slag 세라믹에 의한 산성광산배수의 처리기작에 대한 미세분석 연구)

  • Yim, Soo-Bin
    • Journal of Korean Society of Water Science and Technology
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    • v.26 no.6
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    • pp.13-26
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    • 2018
  • This research was conducted to elucidate the removal mechanism of heavy metals and sulfate ion from acid mine drainage(AMD) by porous zeolite-slag ceramics (ZS ceramics) packed in a column reactor system. The average removal efficiencies of heavy metals and sulfate ion from AMD by the 1:3(Z:S) porous ZS ceramics in the column reactor under the HRT condition of 24 hours were Al 97.5%, As 98.8%, Cd 86.1%, Cu 96.2%, Fe 99.7%, Mn 64.1%, Pb 97.2%, Zn 66.7%, and $SO_4{^{2-}}$ 76.0% during 121 days of operation time. The XRD analysis showed that the ferric iron from AMD could be removed by adsorption and/or ion-exchange on the porous ZS ceramics. In addition it was known that Al, As, Cu, Mn, and Zn could adsorb or coprecipitate on the surface of Fe precipitates such as schwertmannite, ferrihydrite, or goethite. The EDS analysis revealed that Al, Fe, and Mn, which were of relatively high concentration in the AMD, would be adsorbed and/or ion-exchanged on the porous ZS ceramics and also exhibited that Al, Cu, Fe, Mn, and Zn could be precipitated as the form of metal hydroxide or sulfate and adsorbed or coprecipitated on the surface of Fe precipitates. The microscopic results on the porous ZS ceramics and precipitated sludge in a column reactor system suggested that the heavy metals and sulfate ion from AMD would be eliminated by the multiple mechanisms of coprecipitation, adsorption, ion-exchange as well as precipitation.

Screening and Purification of Superoxide Dismutase Producing Marine Bacterium Using Photochemically Generated Superoxide Ion (광화학적으로 제조된 Superoxide Radical을 이용한 Superoxide Dismutase를 생산하는 해양미생물의 탐색 및 효소정제)

  • 조기웅
    • Korean Journal of Microbiology
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    • v.38 no.2
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    • pp.81-85
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    • 2002
  • A marine bacterium producing superoxide dismutase, strain number B446, was screened with nitrite quantitation method using hydroxy amine and photochemically generated superoxide ion, and the superoxide dismutase was purified through 35-75% ammonium sulfate precipitation, DEAE-Sephadex A-25 ion exchange chromatography, Sephadex G-200 gel filtration chromatography, and High-Q anion exchange chromatography to a yield of 6% and purification fold of 32.3.

Selective Adsorption Properties of Nitrate ion in Sulfate and Nitrate Solution by Bead and Fibrous Hybrid Ion Exchange Bed (비드와 섬유 혼성이온교환 베드를 이용한 황산이온과 질산이온 혼합용액에서 질산이온의 선택 흡착 특성)

  • 황택성;박명규
    • Polymer(Korea)
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    • v.27 no.1
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    • pp.69-74
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    • 2003
  • In this study, we have investigated the adsorption properties for nitrate ion in ground water using mixed resin type hybrid ion exchange (HIXF) and fiber type ion exchanger. Their swelling ratio (4.45 g/g) and ion exchange capacities (2.45 meq/g) were higer than the swelling ratio of IEC and IXF. Adsorption yield increased for nitrate $NO_3^-$ and sulfate $SO_4^{2-}$ ions were optimal at the concentration ratios of nitrate and sulfate below 1.0 and the adsorption yields were 100% and 20%, respectively. On the other hand it was shown that the degree of adsorpted for nitrate to pH 3, but it was little changed in the other pH range. We found that the selective adsorption capacity for nitrate was the optimal the mixing ratios of resin and fibrous ion exchanger of below 0.5.