• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.2
• /
• pp.85-92
• /
• 2011

Evaluation of the removal efficiencies of Fe(II) by reactive sand media coated with manganese (MCS), iron (ICS) and both of iron and manganese (IMCS) was investigated as functions of solution pH ranging from 2 to 9, reaction time and concentration of Fe(II) in a batch reactor using each reactive medium and additional oxidants such as $KMnO_4$ and NaOCl. When only Fe(II) was present in solution without any reactive medium, removal of Fe(II) was quite low below pH 5 due to a slow oxidation of Fe(II) and/or negligible precipitation but greatly increased above pH 5 due to a rapid oxidation of Fe(II) and subsequent precipitation of oxidized Fe species. ICS showed negligible efficiency on the removal of Fe(II) through adsorption. However, an efficient removal of Fe(II) was observed at low solution pH in the presence of IMCS or MCS through rapid oxidation and subsequent precipitation. Removal efficiency of Fe(II) by IMCS in the presence or absence of NaOCl was quite similar. Removal rate of Fe(II) by IMCS and additional oxidants gradually increased as the solution pH increased. From the kinetic experiments, removal pattern of Fe(II) was better described by pseudo-second-order equation than pseudo-first-order equation. A rapid removal of Fe(II) using IMCS in the presence of $KMnO_4$ was observed in the first 10 min. The initial removal rate of Fe(II) using $KMnO_4$ was 14,286 mg/kg hr. In case of using NaOCl, the removal of Fe(II) occurred rapidly in the first 6 hrs and then reached the near-equilibrium state. Removal of Fe(II) on IMCS was well expressed by Langmuir isotherm and the maximum removal capacity of Fe(II) was calculated as 1,088 mg/kg.

• Journal of Energy Engineering
• /
• v.3 no.1
• /
• pp.70-76
• /
• 1994

본 연구는 방사성 폐액의 처리를 목적으로 화학처리와 한외여과막(UF)의 결합공정에 의해서 세슘이온의 제거특성을 조사하였다. 이 공정은 대상핵종과 선택성이 크고 한외여과막에 의해서 분리가 가능한 거대분자를 주입하여 핵종을 결합시키고, 이를 한외여과막에 의해서 분리 제거하는 개념이다. 실험은 흡착제로서 K2Cu3(Fe(CN6)2)를 제조하여 주입하였고 회분식 UF stirred cell를 이용하였으며, 용액의 pH, 세슘이온의 농도 및 K2Cu3(Fe(CN6)2)의 농도에 따라 세슘이온의 제거효율을 측정하였다. 세슘의 제거효율은 pH 및 K2Cu3(Fe(CN6)2)의 몰비에 따라 결정되며, pH가 5∼6에서 높은 제거율을 나타내었고 Cs/K2Cu3(Fe(CN6)2)의 몰비가 1.5 이하에서 90% 이상 제거되었다. K2Cu3(Fe(CN6)2)에 대한 Cs의 결합특성은 Langmuir isotherm형태의 식으로 나타내어 평가하였으며, 이때 세슘이온의 최대 흡착용량은 1.72 mM/mM K2Cu3(Fe(CN6)2) 이었다.

• Journal of Soil and Groundwater Environment
• /
• v.10 no.1
• /
• pp.1-5
• /
• 2005

Nitrate reduction with zero valent iron $(Fe^0)$ has been extensively studied, but the proper treatment for ammonium byproduct has not been reported yet. In groundwater, however, ammonium is regarded as contaminant species, and particularly, its acceptable level is regulated to 0.5 mg-N/L. for drinking water. This study is focused on developing new material to reduce nitrate and properly remove ammonium by-products. A new material, Fe-loaded zeolite, is derived from zeolite modified by Fe(II) chloride followed by reduction with sodium borohydride. Batch experiments were performed without buffer at two different pH to evaluate the removal efficiency of Fe-loaded zeolite. After 80 hr reaction time, Fe loaded zeolite showed about $60\%$ nitrate removal at initial pH of 3.3 and $40\%$ at pH of 6 with no ammonium release. Although iron filing showed higher removal efficiency than Fe-loaded zeolite at each pH, it released a considerable amount of ammonium stoichiometrically equivalent to that of reduced nitrate. In terms of nitrogen species including $NO_3-N$ and $NH_4^+-N$, Fe-loaded zeolite removed about $60\%\;and\;40\%$ of nitrogen in residual solution at initial pH of 3.3 and 6, respectively, while the removal efficiency of iron filing was negligible.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.6
• /
• pp.426-431
• /
• 2011

The objective of this study was to investigate the virus removal from artificial groundwater using Mg-Fe layered double hydroxide (LDH). Batch experiments were conducted under various experimental conditions to examine bacteriophage T7 removal with Mg-Fe LDH. Results showed that the removal of T7 by Mg-Fe LDH was a fast process, reaching equilibrium within 2~3 hrs. Mg-Fe LDH had the virus removal capacity of $1.57{\times}10^8pfu/g$ with a removal percent of 96%. Results also showed that the effect of solution pH on T7 removal was minimal between pH 6.2 and 9.1. The influence of anions ($SO_4^{2-}$, $CO_3^{2-}$, $HPO_4^{2-}$) on T7 removal was significant due to their competition with bacteriophage at the sorption sites on LDH, while the effect of $NO_3^-$ was negligible. This study demonstrated that Mg-Fe LDH could be applied as adsorbents for virus removal in water treatment.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.10 no.1
• /
• pp.68-74
• /
• 2002

This study was performed to examine the availability of electrolysis for removal of remaining biologically refractoty humus and residual color of leachate which is biologically pretreated in domestic waste matter sanitary landfill by recycling to landfill. The obtained results were as follows; 1) The electrolysis of leachate through covered bed represented that the removal efficiency of CODcr and color range from 70~80%, in color removal the only electrolysis for a treatment of leachate meet the critia of effluent. 2) The highest removal efficiency was represented in pH 7~8. 3) At anode used Al, Fe, Stainless the removal efficiency of CODcr and color was high in order of Fe, Al, stainless, in considering the settled ability of reaction product in economic or after electro coagulation the removal efficiency was highest when anode was the Fe electrode. 4) In this study conditions for removed both CODcr and Color ar the same time represented thar anode was used Fe, electrode-distance was 2cm and reaction time was 40min in 8volts.

• Korean Journal of Materials Research
• /
• v.8 no.8
• /
• pp.751-756
• /
• 1998

Effects of remote hydrogen plasma cleaning process parameters on the removal of Fe impurities on Si surfaces and the Fe removal mechanism were investigated. Fe removal efficiency is enhanced with decreasing the plasma exposure time and increasing the rf-power. The optimum plasma exposure time and rf-power are 1 min and 100W. respectively, in the range below 10 min and 100W. Fe removal efficiency is better under lower pressures than higher pressures, and the optimum $\textrm{H}_2$ flow rate was found to be 20 and 60sccm, respectively, under a low and a high pressure. The post-RHP(remote hydrogen plasma) annealing enhanced metallic contaminants removal efficiency, and the highest efficiency was achieved at $600^{\circ}C$. According to the AFM analysis results Si surface roughness was improved by 30-50%, which seems to be due to the removal of particles by the plasma cleaning. Also. Fe impurities removal mechanisms by remote hydrogen plasma are discussed.

• Korean Journal of Heritage: History & Science
• /
• v.40
• /
• pp.413-430
• /
• 2007

This study analyzed the foreign substances in waterlogged archaeological woods and compounds in soil where waterlogged archaeological wood was buried, in order to examine the relationship between burial environment and foreign substances in waterlogged archaeological wood. The XRF(X-ray Fluorescence Spectroscopy) and EDX(Energy Dispersive X-ray) analysis were conducted to examine the effect of iron(Fe) to blacken the waterlogged wood. The XRF results showed that investigated soil contained Si, Al, and Fe. Wood ash contained more sulfur and Fe than any other elements in the EDX analysis. Cellulose and hemicellulose were significantly reduced at the surface of wood, which is the blackened part of waterlogged wood. Foreign substances changed the surface color. These problems could be solved by removal of foreign substances in waterlogged archaeological wood using EDTA(Ethylene Diamine Tetra Acetic acid). The optimum condition to remove Fe from waterlogged wood by EDTA was investigated. To do this, the concentration of Fe removed was measured with various concentration of EDTA-2Na. The optimum pH of EDTA-2Na was figured to be 4.1 to 4.3. As the concentration of EDTA increased, the extracted concentration of Fe also increased. In the case of 0.4 wt% of EDTA-2Na, about 60ppm of Fe was eliminated and was stabilized after 48 hours. In the case of EDTA-3Na, the optimum pH was 7 to 8, and about 10 ppm of Fe was eliminated at 0.4 wt% of EDTA-3Na. In the case of EDTA-4Na, the optimum pH was 10 to 11, and about 20 ppm of Fe was eliminated at 0.4 wt% of EDTA-4Na. In conclusion, the iron(Fe) in waterlogged archaeological wood was removed by EDTA treatment and it increased the whiteness of the surface.

• Resources Recycling
• /
• v.20 no.5
• /
• pp.58-63
• /
• 2011

pH control-precipitation method is used for recovery of EDTA from waste fluid of archeological waterlogged wood conservation treatment. EDTA has been used for eliminating of blacken effect in archeological waterlogged wood which was buried in the ground for long period of time. The black substance is generated by Fe$^{3+}$ in the soil reacted with tannin in the archeological waterlogged wood. In order to remove the black substance in archeological waterlogged wood, EDTA was used. The black substance is eliminated from wood as Fe-EDTA complex are formed, and EDTA is separated and precipitated from Fe-EDTA complexes at pH 2.68 or less. The result of analysis of the precipitated products and the commercial EDTA by FT-IR and FE-SEM showed that precipitated product by pH adjusted was not a type of Fe-EDTA complex, but pure EDTA. In this study, Fe$^{3+}$ from waste fluid of EDTA can be separated by HCl added. EDTA can be recycled by using the method of precipitation of EDTA in a strong acid.

• Applied Chemistry for Engineering
• /
• v.20 no.1
• /
• pp.34-39
• /
• 2009

This study was carried out in order to investigate the decolorization and reduced sludge of real textile wastewater by coagulation process. The aim of the study was to verify the relation between decolorization and coagulants of real textile wastewater treatment processes. Coagulation processes were performed using $FeCl_3$, $FeSO_4$, and $Al_2(SO_4)_3$. Real textile wastewater has a mean concentration for BOD, COD, pH, color to be 800 mg/L, 600 mg/L, 9.7, and 102, respectively. From the experimental results, it was shown that the $FeCl_3$ exhibited higher decolorization at the operating conditions 335~2000 mg/L of coagulants and 500 mg/L NaOH dosage. The efficiency of color removal depended on the wastewater pH and concentration of coagulants.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.9
• /
• pp.2390-2395
• /
• 2009

In the condition of GHSV=$30000\;hr^{-1}$, $NO_x$ removal yield was higher as mole ratio of $SiO_2/Al_2O_3$ for Fe/ZSM-5 was lower regardless of preparation method such as CVD (chemical vapor deposition) and dry impregnation. In addition to this, Fe/ZSM-5 catalyst showed about 50% $NO_x$ removal yield between $350^{\circ}C$ - $400^{\circ}C$ while CO formed significantly. To remove newly formed CO over Fe/ZSM-5, Co-Pt/ZSM-5 was used in conjunction with Fe/ZSM-5 in the series and this demonstrated over 90% removal yield of both NOx and CO at $250^{\circ}C$ and GHSV=$30000\;hr^{-1}$.