Influences of Solution pH and Redox Potential on the Bioleaching of $LiCoO_2$ from Spent Lithium-ion Batteries

Li, Lei,Zeng, Gui-Sheng,Luo, Sheng-Lian,Deng, Xiao-Rong,Xie, Qing-Ji 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.2

The influences of solution pH and redox potential on bioleaching of $LiCoO_2$ from spent lithium-ion batteries using Acidithiobacillus ferrooxidans were investigated. Bioleaching at different initial pH and ferrous ion ($Fe^{2+}$) concentrations were carried out, and electrochemical behavior of $LiCoO_2$ dissolution was examined to study the effect of solution redox potential on the bioleaching process. The results showed maximum cobalt dissolution at initial pH of 1.5 and initial $Fe^{2+}$ concentration of 35 g/L, and cobalt dissolution showed only slight relationship with pH of solution. Nonetheless, there was improvement of cobalt dissolution at higher redox potential. The cyclic voltammograms showed that dissolution rates increase when the solution potentials are higher than 0.4 V, and rapid decrease at 1.3 V. The anodic polarization curves indicated that the corrosion, primary passive, and passivation potentials were 0.420, 0.776 and 0.802 V, respectively.

Influences of Solution pH and Redox Potential on the Bioleaching of LiCoO2 from Spent Lithium-ion Batteries

Lei Li,Gui-sheng Zeng,Shenglian Luo,Xiao-rong Deng,Qing-ji Xie 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.2

The influences of solution pH and redox potential on bioleaching of LiCoO2 from spent lithium-ion batteries using Acidithiobacillus ferrooxidans were investigated. Bioleaching at different initial pH and ferrous ion (Fe2+) concentrations were carried out, and electrochemical behavior of LiCoO2 dissolution was examined to study the effect of solution redox potential on the bioleaching process. The results showed maximum cobalt dissolution at initial pH of 1.5 and initial Fe2+ concentration of 35 g/L, and cobalt dissolution showed only slight relationship with pH of solution. Nonetheless, there was improvement of cobalt dissolution at higher redox potential. The cyclic voltammograms showed that dissolution rates increase when the solution potentials are higher than 0.4 V, and rapid decrease at 1.3 V. The anodic polarization curves indicated that the corrosion, primary passive, and passivation potentials were 0.420, 0.776 and 0.802 V, respectively.

Cardiac Mitochondrial Inner Membrane Anion Channel during Ischemic-Reperfusion Injury

Kang, Sunghyun,Kim, Hyunggyu,Ko, Jaehong,Park, Won Sun,Mohamad Warda,Kim, Nari,Youm, Jae Boum,Han, Jin 이화여자대학교 세포신호전달연구센터 2008 고사리 세포신호전달 심포지움 Vol. No.10

Mitochondria are involved in oxidative phosphorylation, thermogenesis, reactive oxygen species. production, and intracellular Ca^(2+) homeostasis. Mitochondrial dysfunction during metabolic inhibition causes energy depletion and loss of cellular function and integrity, leading to cell death. Mitochondria possess a highly permeable outer membrane and an inner membrane that was originally thought to be relatively impermeable to ions to prevent dissipation of the electrochemical gradient for protons. Ion channels on the mitochondrial inner membrane influence membrane potential(ΔΨ_(m)) and cell function in specific ways that can be detrimental to cell survival. Mitochondrial K^(+) channels(mitoK_(Ca) and mitoK_(ATP)) are important determinants of resistance to ischemic damage and apoptosis, and may be clinically recruitable to prevent cardiac ischemic injury. In contrast, inner membrane anion channel(IMAC) initiates oscillations of mitochondrial redox and membrane potential, and thus might influence the overall function of the cell. In this study we recorded IMAC in cardiac mitochondrial inner membrane using nano patch-clamp techniques, and we tested whether IMAC confers protection against ischemic-reperfusion injury or not. We demonstrated that metabolic inhibition can trigger synchronized oscillations in ΔΨ_(m), ROS production, and mitochondrial redox potential. In the open-channel current-voltage curve, single channel currents with a full unitary conductance of 107 pS were often observed. DIDS, 4'-chlorodiazepham and PK11195 decreased the channel activity and prevented metabolic inhibition-induced ΔΨ_(m) loss. They also protected cardiac myocytes against ischemic-reperfusion injury. We are now trying to confirm the nature and molecular identity of the channel components. Our results suggest that IMAC is present in cardiac mitochondria and plays a role as key arbiters of cell life and death. Our studies may contribute to understanding the close relationship between mitochondrial ion channels, membrane potential, and the overall function of the cell. The ion channels should be present in all cell types containing mitochondria and the implications for normal as well as for pathophysiological cell function are universal.

Review on the use of redox-potential data of soils

Chong Woon Hong(홍종운) 한국토양비료학회 2011 한국토양비료학회 학술발표회 초록집 Vol.2011 No.10

Multi-Season, Continuous Measurements of Redox Potential. Value, Methods and Challenges

Michel Vorenhout 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Corynebacterium glutamicum에 의한 Lysine 생산에 있어서 산화환원 전위가 발효속도론적 특성에 미치는 영향

이진희,김성준,이재홍 한국산업미생물학회 1991 한국미생물·생명공학회지 Vol.19 No.1

2l 발효조에서 pH6.9, 온도 32℃일 때 당밀배지를 이용하여 Corynebacterium glutamicum의 영양요구성 유사체 내성변이주에 의한 라이신 발효시 산화환원전위(ORP)가 라이신 발효속도의 특성에 미치는 영향을 조사하였다. 희석률이 0.1h^-1일 때 탄소원이 제한되건 로이신이 제한되건 산소가 제한되지 않는 한 최대의 대당수율 24%를 보였으며, 이 때의 산화환원 전위 값은 -60 mV와 -100 mV 범위에 해당하였다. 산화환원 전위값이 -130 mV의 매우 낮은 용존산소 조건하에서는 대당수율 및 q_s, q_p 등의 발효 반응속도 상수값들이 크게 감소 하였으며, glycine, alanine, valine을 포함하는 발효 부산물의 축적량이 매우 높아졌다. 반면에 산화환원 전위값이 -40 mV 정도의 높은 용존산소 범위하에서는 많은 양의 arginine(0.38g/l)과 glutamic acid(0.21g/l)가 축적되었다. 이는 라이신 발효에 있어서 산화환원 전위의 조절이 매우 중요함을 보여주는 결과로 사료된다. 연속발효에 의한 라이신의 최대 생산성은 2.41g/l/h로서 유가식 발효 경우보다 2.1배의 높은 생산성을 얻을 수 있었다. The effect of redox potential (ORP) on lysine production by a leucine auxotrophic regulatory mutant of Corynebacterium glutamicum on molasses medium was investigated in a 2-ll jar fermentor at pH 6.0 and 32℃. At a dilution rate of D-0.1h^-1, a maximum yield of Y_(p/s)=0.24 was obtained in either carbon- or leucine-limited chemostat where the redox potential was between -60 mV and -100mV. This level of redox potential corresponded to moderate oxygen deficiency. Under a high oxygen deficient condition of the redox potential of -130 mV (oxygen-limited chemostat), all the kinetic parameters such as Y_(p/s), q_s and q_p were decreased significantly and significant amounts of byproducts including glycine, alanine and valine were accumulated in the culture, indicating that the control of redox potential is important in lysine fermentation. At the redox potential of -40 mV, on the other hand, large quantities of arginine (up to 0.38 g/l) and glutamic acid (up to 0.12g/l) were produced. A maximum loysine productivity of 2.41g/l/h was achieved at -66mV under a carbon-limited condition.

염산용액에서의 황동광 침출에 대한 산화환원전위의 영향

유경근,이재천,정진기,손정수 한국자원공학회 2008 한국자원공학회지 Vol.45 No.1

Redox potential dependence of chalcopyrite leaching has been investigated to improve low leaching rate of chalcopyrite and it was reported that there is an optimum redox potential for high leaching rate in relatively low redox potential zone. In the present study, chalcopyrite leaching test was performed in chloride media with ferric ions at 50℃ or 80℃, and the redox potential dependence was investigated. The concentration of copper increases gradually with time, and then rapidly increases after around 20 minutes at 80℃ and after around 7 hours at 50℃, respectively. Oxidation-reduction potential (ORP) decreases with time because ferrous ions are leached from chalcopyrite. Leaching rate of chalcopyrite is much faster in the experiment at 80℃ than at 50℃. There is the highest leaching rate around 440 mV (vs Ag/AgCl), and this result indicates that chalcopyrite leaching depends on redox potential in chloride media.

Identification of redox potential of cobalt ion in different ionic liquids in light of electron mediator generation

( Perumal Silambarasan ),( G. Muthuraman ),문일식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Ionic liquids properties such as wide potential window and high solubility of air pollutants, considered right preference in air pollutant removal process. Further, electron mediator contained ionic liquid minimizes the potential window and increase the removal efficiency. In this investigation, cobalt ion added in different ionic liquids such as BMIM PF-₆, BMIMCF₃SO₃-, BMIM (CF₃SO₂)-₂ and BMIMBF-₄ to make cobalt ion contained ionic liquid. The FTIR analysis supports the cobalt ion presence. The redox behavior of the different ionic liquids with cobalt ion investigated using Pt electrode. Cyclic voltammetry results demonstrates redox potential of Co²⁺/Co³⁺ varied with various anionic groups containing ionic liquid. The found Co²⁺/Co³⁺ redox potential poses the following potential order found at 1.4V, 1.8 and 2 V for CF₃SO₃- (1.4 V)< (CF₃SO₂)-₂ (1.8 V) < PF-₆ (2 V).

오르니틴 생산을 위한 회분식 배양에서 산화환원전위와 상태변수들간의 상관관계

이태호,나정걸,장용근,정봉현 한국산업미생물학회 1998 한국미생물·생명공학회지 Vol.26 No.2

의료용 아미노산인 오르니틴을 생산하는, 용존산소농도와 pH가 일정하게 유지되는 회분식 배양에서 산화환원전위의 시간에 따른 변화를 주요 발효 상태변수들(균체, 포도당, 오르니틴 농도)과 함께 관찰하였다. 산화환원전위는 배양상태를 반영하는 네 개의 다른 구간을 나타내었으며 특히 균체농도의 변화와 밀접한 관계가 있으며 오르니틴 농도에 의해서도 영향을 받음을 알 수 있었다. 산화환원전위와 발효상태변수들과의 상관관계를 구하기 위해 먼저 오르니틴 및 포도당이 산화환원전위에 미치는 영향을 별도의 실험을 통해 알아보았다. 이들 실험 결과들을 바탕으로 하여 산화환원전위의 발효상태변수에 대한 상관관계를 제시하였다. 이 상관관계는 산화환원전위, 포도당 농도, 균체농도의 on-line data로부터 오르니틴 농도를 on-line 추정하는데 이용될 수 있을 것으로 기대된다. In batch cultures of Brevibacterium ketoglutamicum for the L-ornithine production in which the pH and dissolved oxygen concentration were regulated constant, the profiles of redox potential were observed in parallel with the profiles of state variables such as cell, glucose, and ornithine concentrations. It was found that the redox potential had a close relationship with cell concentration and was also affected by ornithine concentration. The effects of ornithine and glucose on redox potential were examined in a separate series of experiments. Based on the experimental results, a correlation of redox potential to glucose, cell and ornithine concentraions has been proposed. The proposed correlation can be used for on-line estimation of ornithine concentration from on-line data of redox potential, glucose concentration, and cell concentration.

진관내동 생태계보전지역에서 산화환원전위(Redox Potential)의 월별 변화

김재근 한국습지학회 2004 한국습지학회지 Vol.6 No.2

습지에서 물의 효과는 토양 속으로 공기의 확산을 방해한다는 것이다. 이로 인해 습지의 토양 속에서는 산화 상태가 환원상태로 바뀌는 생화학적인 과정을 유도하게 된다. 건조토양이 수화된 토양이 될 때 산화환원전위는 낮아지게 된다. 그러므로 산화환원전위를 통해 토양의 소화된 정도를 알 수 있고, 이를 통해 어느 정도 습지의 화학적 특징이 나타날 지를 예견할 수 있다. 그러므로 본 연구에서는 진관내동 생태계 보전지역의 습지 토양 특성을 파악하기 위하여 2003년 5월부터 2004년 3월까지 산화환원 전위를 측정하였다. 깊이별 산화환원전위는 5월 10 cm 깊이에서 가장 높은 200 mV를 보였고 25 cm 깊이에서 가장 낮은 0 mV를 나타내었다. 이후 모든 깊이에서 낮아져 7월에는 약 -200 mV를 나타내었다. 이는 10월까지 지속되었으며, 이후 깊이가 낮을수록 산화환원전위의 증가폭이 크게 나타났다. 20 cm 깊이에서 측정한 5군데의 결과는 모두 비슷한 변화 양상을 보여주었다. 즉, 식물의 성장기 동안에는 낮은 값을 유지하다가 비성장기에는 증가하였다. 이러한 결과로부터 진관내동 생태계 보전지역의 토양은 환원된 상태의 습지 토양 특성을 잘 나타내고 있으며, 메탄화과정이 일어나고 있음을 알 수 있다. The most significant effect of excess water in wetlands is the isolation of the soil from the atmosphere and the prevention of O2 from diffusing into soil. The blockage of atmospheric O2 induces biological and chemical processes that change soil from oxidized into reduced state. When dry soil develop into hydric soil, redox potential is dropping. The redox potential is a indicator of hydric soil and affect chemical function of wetlands. To reveal characteristics of wetland soil, redox potential was measured in Jinkwannaedong ecological conservation area from May in 2003 to March in 2004. Redox potentials in May ranged from 5 mV at 25 cm depth to 200 mV at 10 cm depth. It decreased to about -200 mV at all depths and continued until October. In winter, redox potential was slowly increased; it was the highest at 5 cm depth and lowest at 20 cm depth. Annual variations of redox potential in 20 cm depth showed the same pattern at 5 sites; low in growing season and high in non-growing season. This results indicates that soils of study sites are in hydric state and methanogenesis is occurring in Jinkwannaedong ecological conservation area.