• Journal of the Mineralogical Society of Korea
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• v.13 no.4
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• pp.205-220
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• 2000

북동태평양 C-C지역의 우리나라 광구에서 산출되는 망간단괴의 내부조직을 크게 주상조직 층상대, 첨상조직 층상대, 첨상조직 괴상대, 첨상조직 다공질대 및 괴상조직 괴상대로 구분하였다. 주상조직 층상대에서는 버나다이트(vernadite)가 가장 우세하게 산출되며, 첨상조직 층상대에서는 부서라이크(buserite)가 함께 산출된다. 첨상조직 괴상대는 부서라이트의 산출이 두드러지며, 부분적으로 토도로카이트(todorokite)가 수반된다. 첨상조직 다공질대는 첨상체 또는 구상체로 이루어지며 부분적으로 괴상조직으로 교대되는데 주로 토도로카이트와 부서라이트로 구성되어 있다. 괴상조직을 갖는 괴상대에서는 토도로카이트와 버네사이트(birnessite)가 부서라이트와 함께 산출된다. 각 조직대별로 미세조직을 이루는 엽리들에 대해 전자현미분석을 실시하였다. 엽리의 화학조성을 구성하는 요인은 상관계수 군집분석에 의해 Mn-K의 Mn군, Cu-Ni-Zn-Mg(Ca-Na)의 Cu-Ni-Mg군 Fe-Co-Ti(Ca-P)의 Fe군과 Si-Al의 Si군 등 네 개군으로 구분된다. 각 조직대는 세 개 또는 네 개의 군으로 구성되며 이들 각군은 단괴에서 산출되는 광물과 밀접한 관계를 가진다. Mn군은 토도로카이트, Cu-Ni-Mg군은 부서라이트, Fe군은 함코발트수산화철광물, 그리고 Si군은 규산염광물에서 주로 기인하는 것으로 생각된다. 엽리의 화학조성은 이들 광물의 조합과 구성광물의 화학조성에 따라 지배되고 한 조직대내에서도 여러종류의 조합을 보이는데 이는 각 조직대의 엽리들의 성인과 밀접한 관련이 있는 것으로 생각된다.

• Journal of the Mineralogical Society of Korea
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• v.23 no.2
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• pp.161-170
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• 2010

Many microbes, including both bacteria and fungi, produce manganese (Mn) oxides by oxidizing soluble Mn(II) to form insoluble Mn(IV) oxide minerals, a kinetically much faster process than abiotic oxidation. These biogenic Mn oxides drive the Mn cycle, coupling it with diverse biogeochemical cycles and determining the bioavailability of environmental contaminants, mainly through strong adsorption and redox reactions. This mini review introduces recent findings based on quantum mechanical density functional theory that reveal the detailed mechanisms of toxic metal adsorption at Mn oxide surfaces and the remarkable role of Mn vacancies in the photochemistry of these minerals.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.313-322
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• 2012

몽골 우기누르 지역 철-망간 광상과 타미르골 지역 철 광상의 광체는 먼곤체지 층 내에 렌즈상으로 협재되는 특성을 갖는다. 이러한 광상은 캠브리아 기에서 실루리아기에 이르는 화산 기원의 퇴적형 광상인 타미르골-요루골 광상구에 해당된다. 우기누르 지역의 철-망간 광체와 타미르골 지역의 철광체는 주로 규암과 편암을 모암으로 하여 먼곤체지 층 내에 렌즈상으로 협재되어 있다. 우기누르지역의 편암이 주로 세리사이트 편암인 데 비해 타미르골 지역은 주로 백운모 편암이 나타나는 차이를 갖는다. 또한 우기누르 지역의 광석은 망간이10에서 12% 함유되나 타미르골 지역의 광석은 망간이 1% 이하로 함량이 낮은 특성을 갖는다. 우기누르 철 망간 광상의 철 광물은 주로 자철석, 적철석이 우세하게 나타나고 기타 철 산화물과 황철석이 미량으로 수반되어 나타나며, 망간 광물은 주로스페사틴, 버네사이트가 우세하게 나타나고 기타망간 산화물이 수반되어 나타난다. 타미르골 지역의 철 광석은 자철석이 우세하게 나타나고 적철석이 수반되며 황철석, 철 산화물, 탄산질 철 등이 미량으로 수반되어 나타난다. 우기누르 철-망간 광상에 대한 육상 자력탐사 결과 높은 자기 이상값을보이는 영역이 지표에서 확인된 광체의 방향과 같은 약 $N30^{\circ}W$ 방향으로 나타나며 지표에서 확인된 광체 이외에 지표에 드러나지 않은 부분에서도 연장되는 것이 확인되었다.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.4
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• pp.241-253
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• 2021

Manganese nodules have been found in the shallow water depth of the Arctic Ocean as well as in the abyssal plains of the Pacific and Indian Oceans, but detailed study for them were rarely investigated. Manganese nodules, collected from the East Siberian Sea through the Arctic Expedition using Araon ice braking vessel, have a high potential for Mn mineral resources because they have high Mn content with high Mn/Fe ratio. This study investigated the external form, size and weight, internal texture for the non-spherical manganese nodule, which has about 7 % of total nodule from the East Siberian Sea. This study also researched the relative Mn-oxide mineral composition using the peak area ratio of X-ray diffraction pattern and their chemical composition. All data obtained from non-spherical nodules were compared with the spherical ones. Ellipsoidal, platy and irregular types are common among 5 groups of non-spherical manganese nodule based on the external form, and major axis and weight have positive relationship. All non-spherical manganese nodules have core mainly composed of mud sediments. The average Mn oxide mineral contents in nodules are birnessite, buserite and todorokite in descending order. Although mineral composition does not show any correlation with the external form, kind of core or internal structure, todorokite and buserite contents tend to increase and birnessite content decrease from the surface to the core in the nodule. Non-spherical manganese nodules have higher Mn content and Mn/Fe ratio than those from the shallow water depth of the Arctic Sea and even in the deep-sea of the Pacific and Indian Ocean. Although non-spherical nodule is larger and heavier, and has lower Mn content and Mn/Fe ratio than spherical nodule, there are not any differences in mineral composition and internal structure between them. Almost all manganese nodules collected from the East Siberian Sea are attributed to diagenetic process, because they are higher than 5 in Mn/Fe ratio.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.73-80
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• 2015

An investigation on the removals of tetracycline (TTC), which is a family of antibiotics widely founded in the environment, from the aqueous solution by birnessite(${\delta}-MnO_2$)-mediated oxidative transformation was described. This study also examined the potential effect of the naturally occurring substances, humic acid (HA) on the oxidative transformation. The experiment was carried out in various conditions (reaction time, Mn oxide loadings, pH) and in the presence of HA as a batch test. The removals of TTC followed pseudo-first order reactions, and rate constants (k, $hr^{-1}$) for the removals of TTC were constantly increased with decreasing pH from 0.98 (pH 9) to 2.97 (pH 3). The rate constants also increased about 1.3 times when the birnessite loading increased from 1 to 2 g/L. Presence of HA (5 mg-C/L, at $pH{\geq}6$) caused some enhancement in the removals of TTC as compared to the control, and also showed the removal efficiencies of TTC in the birnessite mediated systems (TTC=0.25 mM, ${\delta}-MnO_2=2.0g/L$, pH 6) increased with increasing HA concentrations (1~10 mg-C/L). The results obtained from the oxidative transformation of TTC and the effect of HA were discussed in terms of reaction characteristics and mechanism.

• Journal of the Mineralogical Society of Korea
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• v.30 no.4
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• pp.219-227
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• 2017

Manganese (Mn) nodules in the Arctic Sea have been founded in the Kara Sea and Barents Sea, but mineral and chemical compositions have been rarely investigated. In this study, mineralogical and geochemical characteristics of Mn nodules obtained during the Arctic Expedition ARA07C in northern East Siberian Sea were identified, and then genesis of Mn nodules were estimated by using these characteristics. Main manganese oxide minerals constituting the manganese nodule were buserite, birnessite, and vernadite. The Mn nodules generally represent radiated and massive texture, and the layered texture was developed restrictively. The radiated texture, main feature of the manganese nodule in the East Siberian Sea, is mainly composed of cuspate-globular microstructure. Compared with the Mn nodules in Pacific and Indian Oceans, Mn nodules of the East Siberian Sea are abundant in Mn, but Fe is too scarce. There was no difference in the chemical composition and microstructures between outer and inner part of nodule. Therefore, nodules are most likely to have only one genesis during their growth, and all of nodules indicate the diagenetic in $Mn-Fe-(Cu+Ni+Co){\times}10$ ternary diagram. It is considered that the manganese nodules in the East Siberian Sea are characterized by high Mn contents because manganese contents in the Arctic Ocean were mainly resulted from river or coastal erosion and most of them are trapped in the Arctic Ocean.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.409-421
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• 2022

Achieving a highly resolved spatial distribution of Mn-bearing minerals and elements in the natural ferromanganese nodules can provide detailed knowledge of the temporal variations of geochemical conditions affecting the formation processes of nodules. While a recent study utilizing Raman spectroscopy has reported the changes in the manganate mineral phases with growth for spherical nodules from the Arctic Sea, the distributions of minerals and elements in the nodules from the shallow Arctic Sea with non-spherical forms have not yet fully elucidated. Here, we reported the micro-laser Raman spectra with varying data acquisition points along three different profiles from the center to the outermost rim of the non-spherical ferromanganese nodules collected from the East Siberian Sea (~73 m). The elemental distributions in the nodule (such as Mn, Fe, etc.) were also investigated by energy dispersive X-ray spectroscopy (EDS) analysis to observe the internal structure and mineralogical details. Based on the microscopic observation, the internal structures of a non-spherical nodule can be divided into three different regions, which are sediment-rich core, iron-rich substrate, and Mn-Fe layers. The Raman results show that the Mn-bearing mineral phases vary with the data acquisition points in the Mn-Fe layer, suggesting the changes in the geochemical conditions during nodule formation. In addition, we also observe that the mineral composition and structural characteristics depend on the profile direction from the core to the rim. Particularly, the Raman spectra obtained along one profile show the lack of Fe-(oxy)hydroxides and the noticeably high crystallinity of Mn-bearing minerals such as birnessite and todorokite. On the other hand, the spectra obtained along the other two profiles present the presence of significant amount of amorphous or poorly-ordered Fe-bearing minerals and the low crystallinity of Mn-bearing minerals. These results suggest that the diagenetic conditions varied with the different growth directions. We also observed the presence of halite in several layers in the nodule, which can be evidence of the alteration of seawater after nodule formation. The current results can provide the opportunity to obtain detailed knowledge of the formation process and geochemical environments recorded in the natural non-spherical ferromanganese nodule.