• Title/Summary/Keyword: $SO_4^{2-}$

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Inorgainc fouling and it fouling reduction in direct contact membrane distillation process (직접 접촉식 막 증발공정에서 무기 막오염 특성 분석 및 저감방법)

  • Lee, Tae-Min;Kim, Seung-Hyun
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.2
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    • pp.115-125
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    • 2020
  • This study was aimed to examine inorganic fouling and fouling reduction method in direct contact membrane distillation(DCMD) process. Synthetic seawater of NaCl solution with CaCO3 and CaSO4 was used for this purpose. It was found in this study that both CaCO3 and CaSO4 precipitates formed at the membrane surface. More fouling was observed with CaSO4(anhydrite) and CaSO4·0.5H2O(bassanite) than CaSO4·2H2O(gypsum). CaCO3 and gypsum were detected at the membrane surface when concentrates of SWRO(seawater reverse osmosis) were treated by the DCMD process, while gypsum was found with MED(multi effect distillation) concentrates. Air backwash(inside to out) was found more effective in fouling reduction than air scouring.

Effect of SO42- Ion on Corrosion and Electrochemical Migration Characteristics of Eutectic SnPb Solder Alloy (공정조성 SnPb Solder 합금의 부식 및 Electrochemical Migration 특성에 미치는 SO42- 이온의 영향)

  • Jung, Ja-Young;Yoo, Young-Ran;Lee, Shin-Bok;Kim, Young-Sik;Joo, Young-Chang;Park, Young-Bae
    • Korean Journal of Materials Research
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    • v.17 no.1
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    • pp.43-49
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    • 2007
  • Electrochemical migration phenomenon is correlated with ionization of anode electrode, and ionization of anode metal has similar mechanism with corrosion phenomenon. In this work, in-situ water drop test and evaluation of corrosion characteristics for SnPb solder alloys in $Na_2SO_4$ solutions were carried out to understand the fundamental electrochemical migration characteristics and to correlate each other. It was revealed that electrochemical migration behavior of SnPb solder alloys was closely related to the corrosion characteristics, and Sn Ivas primarily ionized in ${SO_4}{^2-}$ solutions. The quality of passive film formed at film surface seems to be critical not only for corrosion resistance but also for electrochemical migration resistance of solder alloys.

Hydration in the System of Anhydrite II-Blastfurnace Slag (무수석고-고로슬래그계의 수화반응)

  • 송종택;고상열;노재성
    • Journal of the Korean Ceramic Society
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    • v.34 no.8
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    • pp.861-869
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    • 1997
  • In order to investigate the reaction in the system of anhydrite II-blast furnace slag, the paste hydration which made up with a liquid/solid ratio of 0.45 for 1, 3, 7, 14, 28days by the addition of accelerators to 10~30wt.% slag with natural gypsum calcined for 1hour at 500/$700^{\circ}C$ was studied by combined water determination, XRD, DTA, DSC and SEM. As a result of this experiment, it was found that hydration rate was faster in the system calcined at 50$0^{\circ}C$. Therefore the anhydrite was converted to calcium sulfate dihydrate in the hydration for 1day but the slag was not almost reacted. For the gypsum calcined at $700^{\circ}C$, the hydraton rate in the system of K2SO4 addition was faster than others in the earier period, but the activated effect of the system of Al2(SO4)3 addition was regarded as the highest over 3days. As the amount of slag was increased, they dydration rate was delayed and ettringite was observed in the case of K2SO4 system. However both Al2(SO4)3 and AlK(SO4)2 systems showed calcium sulfate dhydrate only as hydrated products.

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Characteristics on Stream Water Quality in the Northeastern Part of Puk'ansan National Park(III) - With a Special Reference to the Factor Influenced on Stream Water Quality Pollution - (북한산국립공원(北漢山國立公圓) 북동사면(北東斜面) 일대(一帶) 계류수질(溪流水質) 특성(特性)(III) - 계류수질(溪流水質) 오염(汚染)에 미치는 영향인자(影響因子)를 중심(中心)으로 -)

  • Park, Jae Hyeon
    • Journal of Korean Society of Forest Science
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    • v.89 no.3
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    • pp.297-305
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    • 2000
  • This research was conducted to analyze the factors influenced on stream water quality pollution in the northeastern part of Puk'ansan National Park from July, 1998 to November, 1999. The number of visitor and the percentage of the amount of $Cl^-$ resulted in the increase of electrical conductivity, which affected on pollution of the stream water quality. The relationships between those factors should be statistical significance at the 5% level in multiple regression. The multiple regression equations for the percentage of dissolved oxygen at the stream water quality showed that dissolved oxygen and water temperature had statistical significance at the 1% level. The multiple regression equations for the amount of $Cl^-$ at the stream water quality showed that electrical conductivity, the amount of cation($K^+$, $Na^+$), the amount of $SO_4{^{2-}}$, total amount of ion, the percentage of the amount of $Cl^-$, and the percentage of the amount of $SO_4{^{2-}}$ had statistical significance at the 5% and 1% level. Also, The multiple regression equations for the amount of $NO_3{^-}$ at the stream water quality showed that the amount of cation($Na^+$, $Ca^{2+}$), the amount of $SO_4{^{2-}}$, the percentage of the amount of $Cl^-$, and the percentage of the amount of $NO_3{^-}$ had statistical significance at the 5% and 1% level. The multiple regression equations for the amount of $SO_4{^{2-}}$ at the stream water quality showed that the amount of $NO_3{^-}$, total amount of ion had statistical significance at the 5% level.

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Study of the $SO_2$ combustion gases occurring from a livestock waste biogas power system (축산바이오가스발전시스템 가동 시 발생되는 연소 배기가스 중 $SO_2$에 관한 연구)

  • Choi, Jaejoon;Jung, Daehun;Park, Byungsik;Park, Jinsung;Huh, Changsu
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.173.2-173.2
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    • 2011
  • 대체 에너지 자원 중 폐기물의 소화 가스를 이용한 바이오가스 발전은 이산화탄소에 비해 온실효과 영향력에 21배에 해당하는 메탄가스를 연료로 사용하여 환경부하를 저감시키고 에너지를 생산한다. 바이오가스에 포함된 $H_2S$는 연소 후 $SO_2$형태로 발생되는데 $SO_2$는 수분과 반응을 하게 되면 $H_2SO_4$등의 강한 산성을 띄는 물질로 생성되어 배관 및 발전기에 손상을 주고 저온부식현상을 유발하게 하며, 동물이나 인체에 노출되면 기관지 수축현상이 일어나 호흡기에 영향을 주는 질식성을 띄는 가스이다. 축산바이오가스에 포함된 $H_2S$의 함유량과 가스엔진의 연소 시 배출되는 $SO_2$ 배기가스 성분의 관련성을 검증하기 위해 60-65%의 $CH_4$와 30-35%의 $CO_2$ 성분의 바이오가스를 50kW급 발전기에서 사용하였고 연소 후 배출되는 가스 성분을 분석하였다.

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Origin of B, Br and Sr in Groundwater from Bukahn-myeon, Yeongcheon, Gyeongbuk Province, with Emphasis on Hydrochemistry (지하수의 수질화학적 특징과 붕소, 브롬, 스트론튬 성인에 대한 고찰)

  • Choo, Chang-Oh;Lee, Jin-Kook;Lee, Chang-Joo;Park, Ki-Ho;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.19 no.2
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    • pp.235-250
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    • 2009
  • Environmental elements such as B, Br, and Sr in groundwater from Bukahn-myeon, Yeongcheon, Gyeongbuk Province, were investigated in order to know their origin with emphasis on hydrochemistry. pH ranges from 7.37 to 8.39. B content is 0.41${\sim}$4.62 mg/L with an average 1.74 mg/L and Br content is 0${\sim}$3.24 mg/L with an average 2.22 mg/L, and Sr content is 0.93${\sim}$8.64 mg/L with an average 2.76 mg/L. The water types plotted by the Piper diagram are different but mostly $Ca-HCO_3$. Some constituents contributing to EC are Na, $SO_4$, Cl with high determinative coefficients($R^2$) of 0.85, 0.70, 0.90, respectively. The coefficients($R^2$) of Cl to Na, K, $SO_4$ are 0.54, 0.68, 0.53, respectively. It should be noted that there are high cocfficients($R^2$) of B-Sr and $Sr-SO_4$ with 0.65, 0.64, respectively. The Cl/Br ratios are 5.21${\sim}$30.70 due to significant depletion of Cl. The $SO_4/Cl$ ratios are 1.32${\sim}$27.24 with an average of 5.92, ascribed to abundant introduction of $SO_4$ or significant depletion of Cl. Chemical speciation calculated shows that B exists mostly as $H_3BO_3$ with less $H_2BO^-_3$ and Br exists as only $Br^-$. Sr exists mostly as $Sr^2$ with less $SO_4$. Saturation index represents that goundwater is supersaturated with respect to barite, kaolinite, illite, K-mica, and smectite while it is slightly undersaturated with respect to silica, gypsum, anhydrite, talc, chrysotile, feldspar, kaolinite, illite, K-mica, and smectite. The saturation index of celestine is -2.23${\sim}$-0.13 indicating more Sr can be incorporated into groundwater. Groundwater is still much undersaturated to halite. It is likely that the origin of S and Sr was related to the Yucheon volcanic rocks. Br might be originated from the local geological features with introduction of anthropogenic matters.

Effects of Nutritional Sources on Degradation of Polychlorinated Biphenyls (PCBs) by Pseudomonas sp. P2 (Pseudomonas sp. P2에 의한 Polychlorinated Biphenyls(PCBs) 분해에 대한 영양원의 영향)

  • 최상기;금정호
    • Journal of Environmental Science International
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    • v.5 no.5
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    • pp.611-617
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    • 1996
  • The effects of nutritional sources on growth of Pseudomonas sp. P2 were investigated in medium containing biphentyl as a carbon source. To determine characterization of Pseudomonas sp. P2, the incubation time was determined to 100 h of the log phase in the growth curve. The optimal compositions for the growth of Pseudomonas sp. P2 degrading polychlorinated biphenyls (PCBs) were 1000 mg/L $NH_4NO_3$, 1000mg/L KH_2PO_4$, 100mg/L MgSO_4$.$7H_2O$, 30mg/L $CaCl_2$.$2H_2O$, 200mg/L NaCl, and 10mg/L $FeSO_4$.$7H_2O$. Pseudomonas sp. P2 showed the degradability of 59.3%, 57.6%, 51.4%, and 48.7% at 500mg/L, 1000mg/L, 1500mg/L, and 2000mg/L of the PCBs within insulating oil after 100 h incubation under the optimum conditions, respectively.

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Fabrication of LiNiO2 using NiSO4 Recovered from NCM (Li[Ni,Co,Mn]O2) Secondary Battery Scraps and Its Electrochemical Properties (NCM(Li[Ni,Co,Mn]O2)계 폐 리튬이차전지로부터 NiSO4의 회수와 이를 이용한 LiNiO2 제조 및 전기화학적 특성)

  • Kwag, Yong-Gyu;Kim, Mi-So;Kim, Yoo-Young;Choi, Im-Sic;Park, Dong-Kyu;Ahn, In-Sup;Cho, Kwon-Koo
    • Journal of Powder Materials
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    • v.21 no.4
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    • pp.286-293
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    • 2014
  • The electrochemical properties of cells assembled with the $LiNiO_2$ (LNO) recycled from cathode materials of waste lithium secondary batteries ($Li[Ni,Co,Mn]O_2$), were evaluated in this study. The leaching, neutralization and solvent extraction process were applied to produce high-purity $NiSO_4$ solution from waste lithium secondary batteries. High-purity NiO powder was then fabricated by the heat-treatment and mixing of the $NiSO_4$ solution and $H_2C_2O_4$. Finally, $LiNiO_2$ as a cathode material for lithium ion secondary batteries was synthesized by heat treatment and mixing of the NiO and $Li_2CO_3$ powders. We assembled the cells using the $LiNiO_2$ powders and evaluated the electrochemical properties. Subsequently, we evaluated the recycling possibility of the cathode materials for waste lithium secondary battery using the processes applied in this work.

Synthesis of Zn-intermediate from alkali agents and its transformation to ZnO crystallinity (알칼리 침전제에 의해 제조된 아연 중간생성물 및 산화아연 결정화)

  • Jang, Dae-Hwan;Kim, Bo-Ram;Kim, Dae-Weon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.31 no.6
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    • pp.270-275
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    • 2021
  • ZnO was synthesized according to the transformation behavior and crystallization conditions of Zn-intermediate obtained by zinc sulfate as a precursor and NaOH, Na2CO3 as a alkali agents. For ZnO crystallization, Zn4(OH)6SO4·H2O and Zn5(OH)6(CO3)2·H2O as a Zn-intermediate were calcined at 400℃ and 800℃ for 1 h, respectively, based on decomposition temperature from TGA. Zn4(OH)6SO4·H2O was confirmed to have mixed Zn4(OH)6SO4·H2O and ZnO at 400℃, and was completely thermally decomposed at 800℃ to form ZnO phase. The prepared Zn5(OH)6(CO3)2·H2O as a Zn-intermediate by the reaction with Na2CO3 was transformed to a complete ZnO crystallization over 400℃. Nano-sized ZnO can be synthesized at a relatively lower calcination temperature through the reaction with Na2CO3.

New synthetic medium for growth of mycelium of Pleurotus species (느타리속(Pleurotus species) 균의 균사 배양을 위한 새로운 합성 배지)

  • Park, Won-Mok;Kim, Gyu-Hyun;Hyeon, Jae-Wook
    • The Korean Journal of Mycology
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    • v.23 no.3 s.74
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    • pp.275-283
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    • 1995
  • The nutritional requirements of mycelial growth for Pleurotus spp. were studied. As the carbon sources, soluble starch and dextrin, nitrogen sources, arginine and ammonium tartrate, and calcium sources, $CaCO_3$ enhanced mycelial growth. Optimum C/N ratio was 100 : 1. On the base of results from the experiment on nutritional requirements, the following receipe is suggested for growth of Pleurotus spp.; starch 15 g, arginine 3.484 g, ammonium tartrate 3.06 g, $CaCO_3$ 0.314 g, $KH_2PO_4$ 8.138 g, $K_2HPO_4$ 1.584 g, $MgSO_4{\cdot}7H_2O$ 1.5 g for P. sajor-caju and 2.5 g for P. ostreatus. $FeSO_4{\cdot}7H_2O$ 0.02 g, $ZnSO_4{\cdot}7H_2O$ 0.03 g, $MnSO_4{\cdot}7H_2O$ 0.02 g, optimum pH 6.0. This new synthetic medium is tentatively designated as Park's medium.

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