• Journal of Radiation Protection and Research
• /
• v.11 no.1
• /
• pp.15-21
• /
• 1986

The chemical effects resulting from the capture of the thermal neutrons by manganese in different crystalline permanganates, that is, potassium permanganate, sodium permanganate, silver permanganate, barium permanganate and ammonium permanganate, have been investigated. The distribution of radioactive manganese formed has been determined by using different absorbents and ion-exchangers, that is, manganese dioxide, alumina, Zeolite A-3, Kaolinite and Dowex-50. The distribution of radioactive manganese in various adsorbents and ion-exchangers has almost similar result for each permanganate. The affinity for radioactive manganous ion is greatest for Dewex-50. A significant increase of retention is shown through the thermal annealing and the retention depends on the first ionization potential of metal ion in permanganates.

• Economic and Environmental Geology
• /
• v.50 no.6
• /
• pp.545-554
• /
• 2017

Birnessite is one of the dominant Mn (oxyhydr)oxide phases commonly found in soil and deep ocean environments. It typically occurs as nano-sized and poorly crystalline aggregates in the natural environment. It is well known that birnessite participates in a wide variety of bio/geochemical reactions as a reactive mineral phase with structural defects, cation vacancies, and mixed valences of structural Mn. These various bio/geochemical reactions control not only the fate and transport of inorganic and organic substances in the environment, but also the formation of diverse Mn (oxyhydr)oxides through birnessite transformation. This review assessed and discussed about the phase transformation of birnessite under a wide range of environmental conditions and about the potential geochemical factors controlling the corresponding reactions in the literature. Birnessite transformation to other types of Mn (oxyhydr)oxides were affected by dissolved Mn(II), dissolved oxygen, solution pH, and co-existing cation (i.e., $Mg^{2+}$). However, there still have been many issues to be unraveled on the complex bio/geochemical processes involved in the phase transformation of birnessite. Future work on the detail mechanisms of birnessite transformation should be further investigated.

• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.2
• /
• pp.207-213
• /
• 2016

This study is focused on manganese (Mn(II)) removal by potassium permanganate ($KMnO_4$) in surface water. The effects of bicarbonate on Mn(II) indicated that bicarbonate could remove Mn(II), but it was not effectively. When 0.5 mg/L of Mn(II) was dissolved in tap water, the addition of $KMnO_4$ as much as $KMnO_4$ to Mn(II) ratio is 0.67 satisfied the drinking water regulation for Mn (i.e. 0.05 mg/L), and the main mechanism was oxidation. On the other hand, when the same Mn(II) concentration was dissolved in surface water, the addition of $KMnO_4$, which was the molar ratio of $KMnO_4/Mn(II)$ ranged 0.67 to 0.84 was needed for the regulation satisfaction, and the dominant mechanisms were both oxidation and adsorption. Unlike Mn(II) in tap water, the increasing the reaction time increased Mn(II) removal when $KMnO_4$ was overdosed. Finally, the optimum conditions for the removals of 0.5 - 2.0 mg/L Mn(II) in surface water were both $KMnO_4$ to Mn(II) ratio is 0.67 - 0.84 and the reaction time of 15 min. This indicated that the addition of $KMnO_4$ was the one of convenient and effective methods to remove Mn(II).

• Clean Technology
• /
• v.17 no.4
• /
• pp.353-362
• /
• 2011

In our nature, the utilization of rainwater is essential for healthy water recirculation. This is one of the solutions of the increment of impermeability surface according to the development of new cities; this study of the improvement of rainwater quality has been carried on through the improvement of collecting and restoring system of rainwater. The southwestern region of Daejeon City, the rainwater coefficient of run off was 0.40 and this number had computed to 0.59 after the development. After filtration of rainwater, the heavy metal (Cu, As, Cr, Fe, Mn) contents level were lower than underground water. Moreover, collected rainwater showed better quality than underground water in following criteria; hardness, permanganate consumption quality, chloride, evaporation residue, sulfates and nitrate nitrogen. This water quality met the gray water quality standards. The rainwater quality was still suitable to use as bathroom flushing and gardening after 100 days of storage. This study proved that modification (installation of cover with gutter to existing rainwater collection system, proper filtering, and installation of underground storage tank) of collection system could improve quality of water and maintain this approximately 100 days.

• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.4
• /
• pp.313-321
• /
• 2023

Numerous studies have investigated the adsorptive sequestration of radioactive cesium in the natural environment. Among these studies, adsorption onto minerals and high-temperature treatment stand out as highly effective, as demonstrated by the use of zeolite. In this study, cesium was ion-exchanged with birnessite and subsequently underwent high-temperature treatment up to 1100℃ to investigate both mineral phase transformation and the leaching characteristics of cesium. Birnessite has a layered structure consisting of MnO₆ octahedrons that share edges, demonstrating excellent cation adsorption capacity. The high-temperature treatment of cesium-ion-exchanged birnessite resulted in changes in the mineral phase, progressing from cryptomelane, bixbyite, birnessite to hausmannite as the temperature increased. This differs from the phase transformation observed in the tunneled manganese oxide mineral todorokite ion-exchanged with cesium, which shows phase transformation only to birnessite and hausmannite. The leaching of cesium from cesium-ion-exchanged birnessite was estimated by varying the reaction time using both distilled water and a 1 M NaCl solution. The leaching quantity changed according to the treatment temperature, reaction time, and type of reaction solution. Specifically, the cesium leaching was higher in the sample reacted with 1 M NaCl compared to the sample with distilled water and also increased with longer reaction time. For the samples reacted with distilled water, the cesium leaching initially increased and then decreased, while in the NaCl solution, the leaching decreased, increased again, and finally nearly stopped like the sample in the distilled water for the sample treated at 1100℃. These changes in leaching are closely associated with the mineral phases formed at different temperatures. The phase transformation to cryptomelane and birnessite enhanced cesium leaching, whereas bixbyite and hausmannite hindered leaching. Notably, hausmannite, the most stable phase occurring at the highest temperature, demonstrated the greatest ability to inhibit cesium leaching. This results strongly suggest that high-temperature treatment of cesium-ion-exchanged birnessite effectively immobilizes and sequesters cesium.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.10 no.5
• /
• pp.362-366
• /
• 2000

$Li_{0.44}MnO_2$cathode material has high reversibility during lithium insertion processes and is not easily damaged through over-charging or over-discharging. $Mn_2O_3$is often present as an impurity phase, and reduce the electrochemical capacity of electrode because this phase is electrochemically inert. Adding of excess NaOH reduced the $Mn_2O_3$to the content under undetectable by X-ray diffraction. Because the capacity can be increased in the cathode materials with larger unit cell, some of the manganese was replaced with titanium having larger ion size, and powders with the formula $Li_{0.44}T_{iy}Mn_{1-y}O_2$(where y = 0.11, 0.22, 0.33, 0.44, and 0.55) was synthesized and characterized. A maximum reversible capacity of 150 mAh/g was obtained for $Li/P(EO)_8$LiTFSI/$Li_{0.44}Ti_{0.22}Mn_{0.78}O_2$cells in electrochemical potential spectroscopy (ECPS) experiments. Cells with the titanium-doped manganese oxides exhibited a fade rate of 0.12 % or less per cycle.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.441-445
• /
• 2005

태화강 주변지역 지하수의 계절적 수질 변화를 보고자 현장측정 항목(수온, pH, 알칼리도, 전기전도도), 일반 항목(증발잔류물, 총경도, 과망간산칼륨소비량), 음이온물질$(F^-,\;Cl^-,\;{NO_3}^-,\;{SO_4}^{2-})$, 양이온물질$(Ca^{2+},\;Mg^{2+},\;K^+,\;Na^+)$등으로 구분하여 분석하였으며, 총 70개 지점을 대상으로 2004년 5월, 10월 2회에 걸쳐 실시하였다. 지역별 수질특성을 살펴보면 남구지역은 $Ca-Mg-HCO_3,\;Ca-Mg-HCO_3-Cl,\;Ca-Mg-Na-Cl-HCO_3,\;Na-Cl-HCO_3$의 4가지 유형이 전체 시료의 74%를 차지하였으며, $Ca-Mg-HCO_3$형이 가장 우세하게 나타났고, 중구지역 지하수에서는 $Ca-Mg-HCO_3-Cl,\;Ca-Mg-Na-HCO_3-Cl,\;Ca-Mg-HCO_3$의 3가지 유형이 전체 시료의 60%를 차지하는 것으로 나타났으며, 이중에서 $Ca-Mg-HCO_3-Cl$형이 가장 우세하게 나타났다. 두 지역의 수질 변화를 살펴보면. 전기전도도는 남구는 $731.5{\mu}s/m^3$에서 $529.8{\mu}s/m^3$, 중구는 $752.6{\mu}s/m^3$에서 $621.6{\mu}s/m^3$로 201.7, $131.0{\mu}s/m^3$만큼 작아져 두 지역 모두 같은 양상을 보였으나, Hardness 및 TDS의 경우 남구지역은 5월보다 10월에 평균, 최대값이 모두 낮게 나타났다. 또한 $Cl^-$의 경우 지역적, 계절적으로 큰 차이를 보이고 있으며 남구는 5월 68.2mg/l, 10월에는 61.7mg/l로 다소 감소하였으나 중구의 경우 5월 75.5mg/l, 10월 122.1mg/l로 다소 증가한 것으로 나타났다. 양이온 분포 비율 및 농도는 비슷하게 나타났으며, 계절적으로 5월보다 10월에 모두 높게 나타났다. 두 지역 모두 양이온물질 중 나트륨의 분포비율 및 농도가 5월보다 10월에 다소 높게 나타났다. 연구 지역 지하수의 계절적 수질변화를 살펴보면 두 지역간의 지하수질 및 분포특성에 있어 다소 차이를 보이고 있으며, 특히 중구 지역에서 5월보다 10월에 나트륨과 염소이온의 증가가 다소 나타나는 것으로 관찰되었다. 또한 연구지역 중 특이지점($Cl^-$:1,000mg/l이상)은 남구는 5월에 2개에서 10월에는 3개 지점으로 증가하였으며, 중구는 5월, 10월 모두 4개 지점으로 나타났다.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.6
• /
• pp.538-544
• /
• 1985

This study was carried cut to evaluate the water quality of spring waters in Pusan area(see Fig. 1). In this experiment, twenty-five water samples were collected from 5 stations from December 1983 to August 1984. Range and mean values of constituents of the samples are as follows: pH $5.80{\sim}7.25$, 6.60; water temperature $6.0{\sim}23.0^{\circ}C,\;12.9^{\circ}C$; total residue $33.0{\sim}325mg/l$, 121.2mg/l; alkalinity $4.75{\sim}51.6mg/l$, 24.1mg/l; hardness $9.47{\sim}85.0mg/l$, 30.3mg/l; electrical conductivity $0.495{\sim}2.750{\times}^2{mu}{\mho}/cm,\;1.239{\times}10^2{\mu}{\mho}/cm$;turbidity $0.54{\sim}7.80$NTU, 2.04NTU; $KMnO_4$ consumed $0.51{\sim}8.47mg/l$, 1.96mg/l; chloride ion $4.91{\sim}36.0mg/l$, 12.55mg/l; fluoride ion ND-0.30ppm, 0.08ppm; nitrate-nitrogen ND-8.94mg/l, 1.94m:g/l; nitrite-nirogen ND-0.10mg/l, 0.03mg/l; ammonia-nitrogen ND-0.16mg/l, 0.03mg/l: phosphate-phosphorus ND-0.09mg/l, 0.03mg/l; silicate-silicious $0.42{\sim}22.7ng/l$, 7.96mg/l; copper ND-10.5ppb, 2.46ppb; lead ND-22.7ppb, 3.54ppb; zinc ND-103ppb, 21.33ppb; iron $20.3{\sim}2,800ppb$, 801.72ppb, respectively. Arsenic, cyan, cadmium, manganese, mercury, chrome and phenol were not detected. Total residue, electrical conductivity, turbidity and chloride ion of station 1 (Milrakdong) were higher than others as 178.1mg/l, $2.127{\times}10^2{\mu}{\mho}/cm$, 3.16NTU and 16.32mg/l. The concentration of silicious had a great influence on precipitation. The concentration of fluoride ion of spring waters was lower as 0.08ppm than the criterion for drinking water as 1ppm, while iron was exceed 2.7 times as 801.72ppb.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.11
• /
• pp.603-610
• /
• 2016

This work studies the synthesis of birnessite (${\delta}-MnO_2$), a catalyst of oxidative-coupling reactions, from the powder of spent alkaline manganese batteries (SABP, <8 mesh) and evaluate its reactivity for 1-naphthol (1-NP) removals. Manganese oxides using commercial reagents ($MnSO_4$, $MnCl_2$) and the acid birnessite (A-Bir) by McKenzie method were also synthesized, and their crystallinity and reactivity for 1-NP were compared with one another. 96% Mn and 98% Zn were extracted from SABP by acid leaching at the condition of solid/liquid (S/L) ratio 1:10 in $1.0M\;H_2SO_4+10.5%\;H_2O_2$ at $60^{\circ}C$. From the acid leaching solution, 69% (at pH 8) and 94.3% (pH>13) of Mn were separated by hydroxide precipitation. Optimal OH/Mn mixing ratio (mol/mol) for the manganese oxide (MO) synthesis by alkaline (NaOH) hydrothermal techniques was 6.0. Under this condition, the best 1-NP removal efficiency was observed and XRD analysis confirmed that the MOs are corresponding to birnessite. Kinetic constants (k, at pH 6) for the 1-NP removals of the birnessites obtained from Mn recovered at pH 8 (${Mn^{2+}}_{(aq)}$) and pH>13 ($Mn(OH)_{2(s)}$) are 0.112 and $0.106min^{-1}$, respectively, which are similar to that from $MnSO_4$ reagent ($0.117min^{-1}$). The results indicated that the birnessite prepared from the SABP as a raw material could be used as an oxidative-coupling catalyst for removals of trace phenolic compounds in soil and water, and propose the recycle scheme of SAB for the birnessite synthesis.

• Analytical Science and Technology
• /
• v.28 no.3
• /
• pp.182-186
• /
• 2015

In this study, the porous CuO/MnO₂ catalyst was prepared through the co-precipitation process from an aqueous solution of potassium permanganate (KMnO₄), manganese(II) acetate (Mn(CH₃COO)₂·4H₂O) and copper(II) acetate (Cu(CH₃COO)₂·H₂O). The phase change in MnO₂ was analyzed according to the reaction molar ratio of KMnO₄ to Mn(CH₃COO)₂. The reaction mole ratio of KMnO₄ to Mn(CH₃COO)₂·4H₂O was varied at 0.3:1, 0.6:1, and 1:1. The aqueous solution of Cu(CH₃COO)₂ was injected into a mixed solution of KMnO₄ and Mn(CH₃COO)₂ to 10~75 wt% relative to MnO₂. The Cu ion co-precipitates as CuO with MnO₂ in a highly dispersed state on MnO₂. The physicochemical property of the prepared CuO/MnO₂ was analyzed by using the TGA, DSC, XRD, SEM, and BET. The different phase types of MnO₂ were prepared according to the reaction mole ratio of KMnO₄ to Mn(CH₃COO)₂·4H₂O. The results confirmed that the porous CuO/MnO₂ catalyst with γ-phase MnO₂ was produced in the reaction mole ratio of KMnO₄ to Mn(CH₃COO)₂ as 0.6:1 at room temperature.