• 상하수도학회지
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• 제30권6호
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• pp.663-671
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• 2016

Coagulation/precipitation process has been widely used for the removal of phosphate within domestic wastewater. Although Fe and Al are typical coagulants used for phosphate removal, these have some shortages such as color problem and low sedimentation velocity. In this study, both Fe and Al were used to overcome the shortages caused by using single one, and anionic polymer coagulant was additionally used to enhance sedimentation velocity of the precipitate formed. Batch experiments using a jar test were conducted with real wastewater, which was an effluent of the second sedimentation tank in domestic wastewater treatment plant. Response Surface Methodology was used to examine the responsibility of each parameter on phosphate removal as well as to optimize the dosage of the three coagulants. Economic analysis was also done on the basis of selling prices of the coagulants in the field. Phosphate removal efficiency of Fe(III) was 30% higher than those of Fe(II). Considering chemical price, optimum dosage for achieving residual phosphate concentration below 0.2 mg/L were determined to be 18.14 mg/L of Fe(III), 2.60 mg/L of Al, and 1.64 mg/L of polymer coagulant.

• 한국토양비료학회지
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• 제37권1호
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• pp.41-45
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• 2004

충북지역의 근권 토양으로부터 선발한 인산가용화 균인 Pantoea agglomeraans와 인광석을 복합처리하여 벼(Oryza sativa L.)의 생육 및 인산 흡수량에 미치는 영향을 온실내에서 실험하였다. 본 실험은, 종자에 박테리아를 적용시킨 것(bactenzation), 독립 세포 및 고정화된 세포(immobilized cell)를 접종시킨 후, 인광석 1 g과 2.5 g을 각각 시비한 6처리구와 무처리구로 나누어 비교 실험하였다. 인산가용화균을 접종한 처리구가 무처리구에 비하여 벼의 생육 및 인산 흡수량을 증대하는 경향을 나타냈으며, 특히 1 g의 인광석과 고정화된 Pantoea agglomerans를 접종한 처리구에서 다른 처리구들에 비해 가장 우수한 결과를 나타내었다. Pot 충진물내의 유효인산 농도 또한 미생물 접종 처리구에서 증가하였으며, 벼에 흡수된 전인산량과 정의 상관관계가 성립함을 알 수 있었다.

• 환경생물
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• 제18권4호
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• pp.395-401
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• 2000

질산염과 인산염의 농도가 다른 배지에서 Gymnodinium sanguineum과 Sketetonema costotum의 성장과 세포구성성분을 비교 분석하였다. 질산염은 0, 0.3, 0.6, 0.9, 1.2 mM, 인산염은 0, 15, 30, 45, 60$\mu$M을 각각 첨가한 배지에서 배양하였을 때, 저농도의 질산염 및 인산염 배지에서 G. sanguineum의 성장은 억제되었으나, S. costatum은 성장에 영향을 받지 않은 것으로 나타났다. 저농도의 질산염과 인산염 배지에서 G. sanguineum의 세포내 단백질 및 탄수화물의 양은 감소하였으나, S. costutum은 탄수화물의 양이 조금 증가하는 경향을 보였다. 세포내 지질은 G. sunguineum의 경우 중성지질과 인지질은 변화가 거의 없는 반면, 당지질은 저농도의 질산염 및 인산염에서 크게 감소하였다. 그러나 S. costatum 세포내의 세 종류의 지질의 양은 변화를 보이지 않았다. 이와 같은 결과는 저농도의 질산염 및 인산염 배지에서 와편모조류인 G. sanguineum보다 규조류인 S. costatum이 더 잘 적응할 수 있다는 것을 보여준다.

• 한국토양비료학회지
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• 제45권5호
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• pp.817-821
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• 2012

Soil samples collected from abounded mines of Boryeong area in South Korea were used in isolating bacterial strains and their capacity to solubilize inorganic phosphates and heavy metal tolerance were assessed in vitro. Three different inorganic phosphate sources (Ca phosphate, Fe phosphate, and Al phosphate) and four different heavy metals (Co, Cd, Pb and Zn) each with three concentrations ($100{\mu}g\;mL^{-1}$, $200{\mu}g\;mL^{-1}$, and $400{\mu}g\;mL^{-1}$) were used. The bacterial isolates PSB-1, PSB-2, PSB-3, and PSB-4 solubilized significantly higher amount of Ca phosphate during the first five days of incubation though subsequent drop in soluble phosphorus level in the medium was observed at the later stage (after 5 days) of the incubation. Solubilization of Ca phosphate and Fe phosphate was concomitant with the acidification of the culture medium compared to the control where it remained constant. Isolated strains could solubilize Fe phosphate to certain extent ($25-45{\mu}g\;mL^{-1}$) though solubilization of Al phosphate was found negligible. All the isolates were tolerant to heavy metals (Cd, Pb, and Zn) up to the concentration of $400{\mu}g\;mL^{-1}$ except PSB-1 and PSB-8, which were shown to be vulnerable to Co even at $100{\mu}g\;mL^{-1}$. Heavy metal tolerant strains should be further evaluated for plant growth promoting activities also under field conditions in order to assess their agricultural and environmental significance.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1083-1089
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• 2006

Acid drainage occurs when sulfide minerals are exposed to an oxidizing environment. The objective of this study was to examine the optimum condition for creating a phosphate coating on standard pyrite surfaces for reduction of pyrite oxidation. The solution of $10^{-2}M\;KH_2PO_4\;10^{-2}M\;H_2O_2$ pH 6 was identified as the best phosphate coating agent for the reduction of pyrite oxidation. The formation of an iron phosphate coating on pyrite surfaces was confirmed with ore microscope and scanning electron microscope equipped with energy dispersive spectroscopy. The temperature did not significantly affect on the formation of phosphate coating on the surface of pyrite. However, the phosphate coating was less stable at higher temperature than at lower temperature. The phosphate coating was quitely stable at wide range of pH and $H_2O_2$ concentration. The less than 3.4% of phosphate was dissolved at pH 2.79 and 10.64 and less than 1.0% of phosphate was dissolved at 0.1M $H_2O_2$. On the basis of these results, the phosphate coating can effectively reduce the negative environmental of acid rock drainage.

• Membrane and Water Treatment
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• 제11권1호
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• pp.69-77
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• 2020

Former studies revealed that sepiolite thermally treated at high temperature have high adsorption capacity for phosphate. However, its micron size (75 ㎛) limits its application to water treatment. In this study, we synthesized sepiolite impregnated polysulfone (PSf) beads to separate it easily from an aqueous solution. PSf beads with different sepiolite ratios were synthesized and their efficiencies were compared. The PSf beads with 30% impregnated sepiolite (30SPL-PSf bead) possessed the optimum sepiolite ratio for phosphate removal. Kinetic, equilibrium, and thermodynamic adsorption experiments were performed using the 30SPL-PSf bead. Equilibrium adsorption was achieved in 24 h, and the pseudo-first-order model was suitable for describing the phosphate adsorption at different reaction times. The Langmuir model was appropriate for describing the phosphate adsorption onto the 30SPL-PSf bead, and the maximum adsorption capacity of the 30SPL-PSf bead obtained from the model was 24.48 mg-PO₄/g. Enthalpy and entropy increased during the phosphate adsorption onto the 30SPL-PSf bead, and Gibb's free energy at 35 ℃ was negative. An increase in the solution pH from 3 to 11 induced a decrease in the phosphate adsorption amount from 27.30 mg-PO₄/g to 21.54 mg-PO₄/g. The competitive anion influenced the phosphate adsorption onto the 30SPL-PSf bead was in the order of NO₃^- > SO₄^2- > HCO_3^-. The phosphate breakthrough from the column packed with the 30SPL-PSf bead began after ~2000 min, reaching the influent concentration after ~8000 min. The adsorption amounts per unit mass of 30SPL-PSf and removal efficiency were 0.775 mg-PO₄/g and 61.6%, respectively. This study demonstrates the adequate performance of 30SPL-PSf beads as a filter for phosphate removal from aqueous solutions.

• 농업과학연구
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• 제22권1호
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• pp.96-102
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• 1995

본 연구는 돼지 체외수정란의 발육에 있어서 적절한 에너지 급원을 구명하기 위하여 수행하였는 바, BMOC-II 배양액을 기본배양액으로 하여 여기에 해당과정을 통하여 에너지를 생산하는 glucose와 이 과정에 중요하게 작용하는 phosphate를 실험설계에 따라 첨가한 배 양액에 체외에서 발생된 돼지의 수정란을 배양하여 수정란의 발육에 미치는 영향을 조사하였다. 1. 배양액에 Glucose와 phosphate가 모두 첨가되지 않은 배양액에서 배양된 돼지의 수정란은 15.2%가 4-세포란 이상으로 발육하였으나, 상실배로는 전혀 발육하지 못하였다. 2. 배양액에 첨가된 glucose의 농도는 phosphate의 첨가유무에 관계없이 농도가 높은 처리에서 4-세포기 이상으로 발달한 비율은 감소하였으나, 상실배에 도달한 비율은 증가하는 경향을 나타냈고, phosphate와 함께 첨가되었을 때보다 단독으로 첨가하였을 때가 첨가농도에 관계없이 돼지 체외수정란의 발육능을 증가시켰다.

• 한국토양비료학회지
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• 제28권3호
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• pp.278-286
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• 1995

토양(土壤)에 축적(蓄積)되어 있는 난용성(難溶性) 인산염(燐酸鹽)을 이용(利用)하고자 인산염(燐酸鹽) 가용화능(可溶化能)을 가지고 있는 Pseudomonas putida, Penicillium속(屬) 및 Aspergillus niger를 우리 나라 주요(主要) 경작지(耕作地) 토양(土壤)에서 분리(分離)하여 이들 균(菌)의 용해능(溶解能)을 측정(測定)하였다. 인산염(燐酸鹽) 용해량(溶解量)은 배지내(培地內)의 pH 저하(低下)와 밀접(密接)한 관계(關係)를 가지고 있었다. Pseudomonas putida, Penicillium속(屬)에 비(比)해 Aspergillus niger의 인산염(燐酸鹽) 가용화능(可溶化能)이 높았다. Aspergillus niger에 의한 인산염(燐酸鹽) 종류별(種類別) 최대(最大) 가용화량(可溶化量)은 질소원(窒素源)이 $KNO_3$일 때는 aluminium phosphate 776ppm, hydroxyapatite 665ppm, tai-calcium phosphate 593ppm이었으며 인광석(燐鑛石)은 질소원(窒素源)이 $(NH_4)_2SO_4$일 때 411ppm이었다.

• 상하수도학회지
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• 제35권6호
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• pp.455-463
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• 2021

The adsorption process using GAC is one of the most secured methods to remove of phosphate from solution. This study was conducted by impregnating Cu(II) to GAC(GAC-Cu) to enhance phosphate adsorption for GAC. In the preparation of GAC-Cu, increasing the concentration of Cu(II) increased the phosphate uptake, confirming the effect of Cu(II) on phosphate uptake. A pH experiment was conducted at pH 4-8 to investigate the effect of the solution pH. Decrease of phosphate removal efficiency was found with increase of pH for both adsorbents, but the reduction rate of GAC-Cu slowed, indicating electrostatic interaction and coordinating bonding were simultaneously involved in phosphate removal. The adsorption was analyzed by Langmuir and Freundlich isotherm to determine the maximum phosphate uptake(q_m) and adsorption mechanism. According to correlation of determination(R²), Freundlich isotherm model showed a better fit than Langmuir isotherm model. Based on the negative values of q_m, Langmuir adsorption constant(b), and the value of 1/n, phosphate adsorption was shown to be unfavorable and favorable for GAC and GAC-Cu, respectively. The attempt of the linearization of each isotherm obtained very poor R². Batch kinetic tests verified that ~30% and ~90 phosphate adsorptions were completed within 1h and 24 h, respectively. Pseudo second order(PSO) model showed more suitable than pseudo first order(PFO) because of higher R². Regardless of type of kinetic model, GAC-Cu obtained higher constant of reaction(K) than GAC.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.598-601
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• 2001

Citrobacter sp. Y19 was studied for $H_2$ production from glucose in batch culture. Important conditions studied include phosphate concentration, temperature, glucose concentration, and gas-phase replacement. Optimal $H_2$ production was observed at 140 - 180 mM of phosphate and $36^{\circ}C$. When glucose concentration increased from 0.1 to 5% (w/v), $H_2$ production increased up to 2% and remained constant thereafter. Intermittent purging of the reaction bottle with Ar gas stimulated the $H_2$ production by alleviating the inhibition by $H_2$. The maximum productivity was observed to be 113.2 ml $H_2$/h-1.