Evolution of copper isotopes in arc systems: Insights from lavas and molten sulfur in Niuatahi volcano, Tonga rear arc

Wang, Zaicong,Park, Jung-Woo,Wang, Xia,Zou, Zongqi,Kim, Jonguk,Zhang, Pingyang,Li, Ming Pergamon Press 2019 Geochimica et cosmochimica acta Vol.250 No.-

<P><B>Abstract</B></P> <P>Metal transfer from mantle wedge to primitive arc magmas and subsequent enrichment by magmatic fractionation and volatile exsolution are critical processes for mineralization in arc systems. Copper is one of the most important ore-forming elements whose behavior is sensitive to oxygen fugacity. Copper isotope composition (δ<SUP>65</SUP>Cu) may provide valuable insights into Cu transfer and enrichment in hydrous oxidized arc magmas. However, the extent of Cu isotopic variation in arc systems and its link to Cu transfer and enrichment for ore mineralization have been poorly explored. Here we report the Cu isotopes in basalts, dacites and molten sulfur in Niuatahi volcano, Tonga rear arc to address the issue. These samples, as well as associated black smoker chimneys, represent products of magmatic fractionation and degassing of hydrous oxidized arc magmas with ore mineralization.</P> <P>Sulfide-undersaturated differentiation of basalts in the Niuatahi and their high water content and oxygen fugacity suggest complete exhaustion of sulfides in the mantle source during fluxed melting and transfer of nearly all Cu, Ag and other chalcophile metals to the primary magmas. The δ<SUP>65</SUP>Cu of Niuatahi basalts thus reflect that of the mantle source. The basalts display δ<SUP>65</SUP>Cu of 0.01‰ to 0.17‰ (n = 3; external uncertainty of 0.05‰, 2sd), similar to mid-ocean ridge basalts (MORBs), komatiites and the depleted mantle (0.06 ± 0.20‰, 2sd). These results, together with their Cu contents indistinguishable from MORBs, suggest that oxidized slab components are very likely to have limited influence on the Cu budget and mean δ<SUP>65</SUP>Cu of the mantle wedge.</P> <P>The Niuatahi magma became sulfide saturated after magnetite crystallization during magma differentiation from basalt to dacite. Constant Cu/Ag in the basalts and dacites suggests segregation of immiscible sulfide melts instead of crystalline sulfides. The sulfide segregation significantly decreased contents of Cu and other chalcophile metals but hardly changed δ<SUP>65</SUP>Cu in dacites (−0.01‰ to 0.35‰, n = 11 with a mean of 0.21 ± 0.24‰, 2sd), implying restricted fractionation of δ<SUP>65</SUP>Cu during magnetite fractionation and sulfide melt segregation. Molten sulfurs, which are formed by intensive magmatic degassing of arc lavas and characterized by substantial enrichment of Cu and other metals, show δ<SUP>65</SUP>Cu of 0.30‰ to 0.37‰. These values are indistinguishable from those of comagmatic dacites (0.34‰). Although the published δ<SUP>65</SUP>Cu of sulfide chimneys in the Niuatahi appears slightly lighter (0.00‰ to 0.29‰ ± 0.18‰, 2sd), the overall limited range of δ<SUP>65</SUP>Cu in molten sulfur and sulfide chimneys indicates that discharging magmatic volatiles and hydrothermal venting with significant removal of Cu hardly fractionates δ<SUP>65</SUP>Cu. The δ<SUP>65</SUP>Cu data from arc lavas, molten sulfur and sulfide chimneys thus reveal limited variations in δ<SUP>65</SUP>Cu (within 0.35‰) during fluxed melting, magmatic fractionation, magma degassing and mineralization in arc systems. If these results represent general processes, they imply that the heavier or lighter δ<SUP>65</SUP>Cu in other sulfide chimneys and associated deposits should result from the complex hydrothermal processes and/or low-temperature secondary reworking.</P>

연안 오염퇴적물의 재부상에 의한 중금속의 수계용출특성

송영채(Young Chae Song),수바(Bakthavachallam Subha),우정희(Jung Hui Woo) 大韓環境工學會 2014 대한환경공학회지 Vol.36 No.7

본 연구는 B광역시 북항을 대상으로 해양 퇴적물의 물리화학적 특성과 오염도를 평가하고, 해양 퇴적물의 재부상 시중금속의 용출특성 및 생태적 위험성을 평가하였다. 북항 퇴적물의 주요 구성성분은 미세 실트질 및 점토질이었으며, 유기물질과 산휘발성 황화물이 높게 포함되어 퇴적물 내 함유된 중금속으로 인한 생태적 위험도가 높은 것으로 평가되었다. 회분식 실험결과, 퇴적물의 재부상으로 인한 중금속 용출속도는 납>>구리>크롬>>아연>카드뮴 순이었으며, 중금속 용출은 금속 황화물의 산화반응에 기인하는 것으로 평가되었다. 중금속은 퇴적물의 재부상 약 1시간 내에 급격히 용출되었으며, 재부상에 의한 황화물의 산화는 퇴적물에 존재하는 중금속의 광물내 잔류분율을 증가시키고, 유기물과 결합된 중금속의 분율을 감소시킬 뿐만 아니라 퇴적물에 함유된 중금속의 다른 결합분율의 변화에 영향을 미쳤다. 퇴적물의 재부상에 의하여 해수로 용출되는 중금속의 용출량은 재부상 시간, 금속 황화물의 산화속도와 재부상하는 퇴적물의 농도에 영향을 받았다. The study investigated the physicochemical characteristics and the ecological risk of the Northport sediment in B city and the releasing properties of heavy metals into seawater during the resuspension also studied. The major components of the sediment are fine silt and clay which contains high organic matter and AVS (Acid volatile sulfide) and the ecological risk of the heavy metals in sediment also very high. The release rate of heavy metals into seawater was in order of Pb>>Cu>Cr>>Zn>Cd during the resuspension in a batch experiment, and the heavy metal release mainly attributed to the oxidation of metal sulfides. Heavy metals which came from easily oxidisable metal sulfides rapidly contaminated seawater within about 1.0 h of the sediment resuspension. The sulfide oxidation during the resuspension increased the residual fraction of heavy metals in the sediment, decreased the organic bound fraction, and changed the other fractions of heavy metals in the sediment. The release of heavy metals from the sediment during resuspension was affected by the resuspension time, the oxidation rate of metal sulfides and resuspended concentration of the sediment particle.

Morphology controlled synthesis of 2-D Ni–Ni3S2 and Ni3S2 nanostructures on Ni foam towards oxygen evolution reaction

CHAUDHARINITIN KADUBA,Oh Aram,Sa Young Jin,Jin Haneul,백현석,Kim Sang Gu,이석중,주상훈,Lee Kwangyeol 나노기술연구협의회 2017 Nano Convergence Vol.4 No.7

Catalysts for oxygen evolution reactions (OER) are at the heart of key renewable energy technologies, and development of non-precious metal catalysts with high activity and stability remain a great challenge in this field. Among various material candidates, metal sulfides are receiving increasing attention. While morphology-dependent catalytic performances are well established in noble metal-based catalysts, relatively little is known for the morphology‒catalytic performance relationship in metal sulfide catalysts. In this study, uniform spider web-like Ni nanosheets–Ni3S2 and honeycomb-like Ni3S2 structures are deposited on nickel foam (Ni3S2/NF) by a facile one-step hydrothermal synthetic route. When used as an oxygen evolution electrode, the spider web-like Ni–Ni3S2/NF with the large exposed surface area shown excellent catalytic activity and stability with an overpotential of ~310 mV to achieve at 10 mA/cm2 and a Tafel slope of 63 mV/dec in alkaline media, which is superior to the honeycomb-like structure without Ni nanosheet. The low Tafel slope of the spider web-like Ni–Ni3S2/NF represents one of the best OER kinetics among nickel sulfide-based OER catalysts. The results point to the fact that performance of the metal sulfide electrocatalysts might be fine-tuned and optimized with morphological controls.

Preparation of iron sulfide/carbon nanocomposites as anodes for lithium ion batteries

황호진,신하은,이완진 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

The iron sulfide nanocomposites as anodes were prepared through microemulsion technique for the reverse micelle, calcination process for iron oxide under nitrogen, and subsequent solvothermal method for ion exchange deposition oxide into sulfide. To enhance the rate capability as well as the electrochemical stability, the iron sulfide nanocomposite were synthesized by wrapping the carbon like graphene onto the surface of iron precursor. The carbon-wrapped iron sulfide nanocomposites attribute to better electrochemical performance as follows: (i) by buffering the volume expansion during cycling, and (ii) nanoscaled metal particle offers high surface area, giving the intimate contact between electrolyte and electrodes.

Cd, Ni, Zn로 오염된 퇴적물에 노출된 Neanthes arenaceodentata의 금속 생물축적, 사망 및 성장저해에 대한 Acid Volatile Sulfide(AVS) 영향

이종현,고철환 한국해양학회 2002 바다 Vol.7 No.4

퇴적물 내 황화물(acid volatile sulfide, AVS)이 저서 생물의 금속 생물 축적 및 독성 반응에 어떠한 영향을 미치는 지를 이해하기 위해서 해양 다모류인 Neanthes arenaceodentata를 이용한 퇴적물 노출실험을 수행하였다. 이를 위해서 세 개의 다른 AVS 농도군에 대조구를 포함한 다섯 개의 농도 구배로 Cd, Ni, Zn를 오염시킨 퇴적물에서 N. arenaceodentata를 20일간 배양한 후 실험생물의 체내 금속 축적량과 그에 따른 사망률 및 성장률을 조사하였다. N. arenaceodentata에 의한 금속의 생물축적은 Cd과 Zn의 경우 AVS 농도의 영향을 받아서 해수(overlying water, OW)내 용존 금속 농도에 비례해서 증가했다. Ni은 AVS농도에 영향을 받지 않고 퇴적물 내 금속(simultaneously extracted metals. SEM)농도에 비례해서 증가했다. N. arenaceodentata의 사망과 성장률 저해현상은 SEM과 AVS 간의 몰농도차가 영보다 큰 조건([SEM-AVS]>0)에서만 관찰되었는데 용존 Zn에 의한 결과로 추정되었다. OW-Zn의 20-d LC50값은 9.3(8.0$\pm$11.0) $\mu$M이었다. 사망률에 대한 체내 Zn 농도의 최소영향농도(LOEC)는 7.8 $\mu$mol/g이었고, 최대무영향농도(NOEC)는 6.2$\mu$mol/g이었다. 성장률 저해에 대한 체내 Zn 농도의 LOEC는 5.9$\mu$mol/g이었고, NOEC은5.1 $\mu$mol/g토이었다. 본 실험에서는 실험실 조건에서 인위적으로 오염시킨 퇴적물 내 Zn의 입자상 Zn 농도와 용존 Zn농도의 비 (K$_{d}$ )가 현장 퇴적물에 비해서 10배 정도 감소함으로써 결국 용존 Zn에 의한 독성이 과대평가된 것으로 보인다. A sediment exposure experiment was conducted to investigate the influence of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in sediments on the bioavailability and toxicity of Cd, Ni and Zn to a marine polychaetes Neanthes arenaceodentata. The test animals were exposed to contaminated sediments spiked by metal mixtures of Cd, Ni, Zn (0.5~15 $\mu$mol/g of total SEM) in low (~1 $\mu$mol/g), medium (~5 $\mu$mol/g) and high AVS series (~10 $\mu$mol/g) to determine bioaccumulation, mortality and individual growth rate in each treatment after 20 days. Cd and Zn bioaccumulation in test animals increased with increasing of overlying water (OW) concentration controlled by AVS. In contrast, Ni bioaccumulation increased with increase of SEM concentration. Mortalities and growth inhibitions of N. arenaceodentata observed in only treatments with [SEM-AVS]>0, due to a high level of OW-Zn. With regard to the mortality, the 20-d LC5O value fur OW-Zn was 9.3(8.0$\pm$11.0) $\mu$M. The LOEC (Lowest Observed Effect Concentration) for Tissue-Zn was 7.8 $\mu$mol/g and the NOEC (No Observed Effect Concentration) was 6.2 $\mu$mol/g. Regarding the inhibition of individual growth rate, the LOEC fer Tissue-Zn was 5.9 $\mu$mol/g, and NOEC was 5.1 $\mu$mol/g. In this study, the toxicity of dissolved metals, especially for Zn, was overemphasized due to the reduced distribution coefficients (K$\_$d/s) of metals in the experimental sediments.

Metal sulfides as anode catalysts in direct alkaline sulfide fuel cell

Kim, K.,Son, J.,Han, J.I. Pergamon Press ; Elsevier Science Ltd 2014 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.39 No.20

Effective, stable, and economical anode catalysts are prerequisite for the practical use of a promising sulfide-based fuel cell platform, named direct alkaline sulfide fuel cell (DASFC). In this study, metal sulfides (MeS, Me = Mo, Fe, Co) were investigated as potential candidates suited for such a purpose. Physical and electrochemical properties of MeS catalysts were measured using X-ray diffraction (XRD), cyclic voltammetry (CV), I-V analysis, and electrochemical impedance spectrophotometry (EIS). All MeS catalysts exhibited strong catalytic activity toward sulfide oxidation at alkaline conditions, with the highest performance observed with CoS, recording maximum power density of 29.18 mW cm<SUP>-2</SUP> at 70 <SUP>o</SUP>C. MeS catalysts, with superb sulfur tolerance, appear to be potent anode catalysts for the DASFC application.

Ex-situ Reductive Dechlorination of Carbon Tetrachloride by Iron Sulfide in Batch Reactor

Kyung Hoon Choi,Woo Jin Lee 대한환경공학회 2008 Environmental Engineering Research Vol.13 No.4

Ex-situ reductive dechlorination of carbon tetrachloride (CT) by iron sulfide in a batch reactor was characterized in this study. Reactor scaled-up by 3.5 L was used to investigate the effect of reductant concentration on removal efficiency and process optimization for ex-situ degradation. The experiment was conducted by using both liquid-phase and gas-phase volume at pH 8.5 in anaerobic condition. For 1 mM of initial CT concentration, the removal of the target compound was 98.9% at 6.0 g/L iron sulfide. Process optimization for ex-situ treatment was performed by checking the effect of transition metal and mixing time on synthesizing iron sulfide solution, and by determining of the regeneration time. The effect of Co(II) as transition metal was shown that the reaction rate was slightly improved but the improvement was not that outstanding. The result of determination on the regeneration time indicated that regenerating reductant capacity after 1st treatment of target compound was needed. Due to the high removal rates of CT, ex-situ reductive dechlorination in batch reactor can be used for basic treatment for the chlorinated compounds.

Activation of a Ni electrocatalyst through spontaneous transformation of nickel sulfide to nickel hydroxide in an oxygen evolution reaction

Lee, Minoh,Oh, Hyung-Suk,Cho, Min Kyung,Ahn, Jae-Pyoung,Hwang, Yun Jeong,Min, Byoung Koun Elsevier 2018 Applied Catalysis B Vol.233 No.-

<P><B>Abstract</B></P> <P>Ni-sulfide compounds synthesized on Ni foam by simple thermal sulfurization are employed as electrocatalysts for water oxidation, resulting in superior activity in alkaline electrolyte media. The role of sulfur in Ni-sulfide was found to be an activator that transformed sulfide into hydroxide, which was eventually transformed into (oxy)hydroxide. The Ni-(oxy)hydroxide phase was also found to be layered and/or amorphous. This activated catalyst showed significant enhancement in water oxidation performance with a low overpotential value of 256 mV at current density of 10 mA cm<SUP>−2</SUP>. Our observation could offer important insight into metal-chalcogenide electrocatalyst for water oxidation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electro-oxidation treatment on Ni-sulfide/Ni foam highly improves its OER activity. </LI> <LI> Sulfurization of Ni facilitates the formation of Ni-(oxy)hydroxide layer on the surface. </LI> <LI> Ni<SUB>3</SUB>S<SUB>2</SUB> derived amorphous/crystalline Ni-(oxy)hydroxide mixtures with Fe are active for OER. </LI> <LI> Sulfur in Ni<SUB>3</SUB>S<SUB>2</SUB> activates to form nanoparticle embedded layered structures in amorphous matrix. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Binder-free flexible electrode based on nitrogen-doped cobalt sulfide derived from metal-organic frameworks prepared by in-situ sulfide reaction for supercapacitors

최미영,김석 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.1

Nitrogen-doped cobalt sulfide electrodes derived from carbonized metal-organic frameworks by in-situ sulfide reaction for supercapacitors

최미영,김석 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.-