Lithium intercalation compounds, such as the complex metal oxide, lithium nickel manganese cobalt oxide (LiNi x Mn y Co 1−x−y O 2 , herein referred to as NMC), have demonstrated their utility as energy storage materials. In response to recent concerns about the global supply of cobalt, industrially synthesized NMCs are shifting toward using NMC compositions with enriched nickel content. However, nickel is one of the more toxic components of NMC materials, meriting investigation of the toxicity of these materials on environmentally relevant organisms. Herein, the toxicity of both nanoscale and microscale Ni-enriched NMCs to the bacterium, Shewanella oneidensis MR-1, and the zooplankton, Daphnia magna , was assessed. Unexpectedly, for the bacteria, all NMC materials exhibited similar toxicity when used at equal surface area-based doses, despite the different nickel content in each. Material dissolution to toxic species, namely nickel and cobalt ions, was therefore modelled using a combined density functional theory and thermodynamics approach, which showed an increase in material stability due to the Ni-enriched material containing nickel with an oxidation state >2. The increased stability of this material means that similar dissolution is expected between Ni-enriched NMC and equistoichiometric NMC, which is what was found in experiments. For S. oneidensis , the toxicity of the released ions recapitulated toxicity of NMC nanoparticles. For D. magna , nickel enrichment increased the observed toxicity of NMC, but this toxicity was not due to ion release. Association of the NMC was observed with both S. oneidensis and D. magna. This work demonstrates that for organisms where the major mode of toxicity is based on ion release, including more nickel in NMC does not impact toxicity due to increased particle stability; however, for organisms where the core composition dictates the toxicity, including more nickel in the redesign strategy may lead to greater toxicity due to nanoparticle-specific impacts on the organism.
more »
« less
MnO, Co and Ni Nanoparticle Synthesis by Oleylamie and Oleic Acid
Background: Magnetic nanoparticles are attracting much attention toward easyoperation and size controllable synthesis methods. We develop a method to synthesize MnO, Co,CoO, and Ni nanoparticles by thermal decomposition of metal 2,4-pentanedionates in the presenceof oleylamine (OLA), oleic acid (OA), and 1-octadecene (ODE). Methods: Similar experimental conditions are used to prepare nanoparticles except for the metalstarting materials (manganese 2,4-pentanedionate, nickel 2,4-pentanedionate, and cobalt 2,4-pentanedionate), leading to different products. For the manganese 2,4-pentanedionate startingmaterial, MnO nanoparticles are always obtained as the reaction is controlled with differenttemperatures, precursor concentrations, ligand ratios, and reaction time. For the cobalt 2,4-pentanedionate starting material, only three experimental conditions can produce pure phase CoOand Co nanoparticles. For the nickel 2,4-pentanedionate starting material, only three experimentalconditions lead to the production of pure phase Ni nanoparticles. Results: The nanoparticle sizes increase with the increase of reaction temperatures. It is observedthat the reaction time affects nanoparticle growth. The nanoparticles are studied by XRD, TEM,and magnetic measurements. Conclusion: This work presents a facile method to prepare nanoparticles with different sizes,which provides a fundamental understanding of nanoparticle growth in solution.
more »
« less
- Award ID(s):
- 1912876
- NSF-PAR ID:
- 10403386
- Date Published:
- Journal Name:
- Current Chinese Chemistry
- Volume:
- 2
- Issue:
- 2
- ISSN:
- 2666-0016
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Lithium nickel manganese cobalt oxide (Li x Ni y Mn z Co 1−y−z O 2 , 0 < x , y , z < 1, also known as NMC) is a class of cathode materials used in lithium ion batteries. Despite the increasing use of NMC in nanoparticle form for next-generation energy storage applications, the potential environmental impact of released nanoscale NMC is not well characterized. Previously, we showed that the released nickel and cobalt ions from nanoscale Li 1/3 Ni 1/3 Mn 1/3 Co 1/3 O 2 were largely responsible for impacting the growth and survival of the Gram-negative bacterium Shewanella oneidensis MR-1 (M. N. Hang et al. , Chem. Mater. , 2016, 28 , 1092). Here, we show the first steps toward material redesign of NMC to mitigate its biological impact and to determine how the chemical composition of NMC can significantly alter the biological impact on S. oneidensis . We first synthesized NMC with various stoichiometries, with an aim to reduce the Ni and Co content: Li 0.68 Ni 0.31 Mn 0.39 Co 0.30 O 2 , Li 0.61 Ni 0.23 Mn 0.55 Co 0.22 O 2 , and Li 0.52 Ni 0.14 Mn 0.72 Co 0.14 O 2 . Then, S. oneidensis were exposed to 5 mg L −1 of these NMC formulations, and the impact on bacterial oxygen consumption was analyzed. Measurements of the NMC composition, by X-ray photoelectron spectroscopy, and composition of the nanoparticle suspension aqueous phase, by inductively coupled plasma-optical emission spectroscopy, showed the release of Li, Ni, Mn, and Co ions. Bacterial inhibition due to redesigned NMC exposure can be ascribed largely to the impact of ionic metal species released from the NMC, most notably Ni and Co. Tuning the NMC stoichiometry to have increased Mn at the expense of Ni and Co showed lowered, but not completely mitigated, biological impact. This study reveals that the chemical composition of NMC nanomaterials is an important parameter to consider in sustainable material design and usage.more » « less
-
null (Ed.)Particle nucleation and growth of crystalline manganese oxide nanoparticles was examined in a complementary experimental and modelling study. Gas-to-particle conversion occurred in a flame-assisted chemical vapor deposition process whereby a premixed stagnation flame drove the high-temperature synthesis. The structure of the stagnation flame was computed using pseudo one-dimensional and axisymmetric two-dimensional methods to assess the accuracy of using a faster similarity-based calculation for flame-deposition design. The pseudo one-dimensional computation performs reasonably well for the narrow aspect ratio stagnation flow currently studied as evidenced by reasonable agreement between the measured flame position and both computational methods. Manganese oxide nanoparticles having II, II–III, III or IV oxidation states were observed depending on the flame conditions. These observations may be explained by size-dependent equilibria between nano-scale manganese oxide and surrounding gas-phase oxygen. Local equilibrium was assessed during the particle temperature–oxygen–time history to gain insight into oxide formation in the flame. Analysis of the saturation ratio for formation of condensed MnO in the flame indicates that nucleation may be limited by a thermodynamic barrier. This nucleation mechanism is supported by measured particle sizes smaller than what would be expected from a coagulation limited growth process. Nanocrystalline MnO, reported here for the first time by flame synthesis, was obtained in oxygen lean flames. MnO 2 is the phase predicted to be thermally stable as the particles approach the deposition surface, yet other metastable oxide phases were produced in many of the flames examined. In fact, MnO 2 was only observed in the smallest particle size conditions which may indicate that high cooling rates limit phase equilibrium to less massive particles.more » « less
-
more » « less
Abstract Macronutrients and trace metals are incorporated into phytoplankton during growth and regenerated back into the water column when phytoplankton decay, a process that contributes to the distributions of dissolved trace metals and macronutrients in depth profiles. To study this, we incubated mixed Gulf of Mexico phytoplankton assemblages and monocultures of the diatom
Pseudo‐nitzschia dolorosa and the dinoflagellateKarenia brevis in the dark. Over 6 months, macronutrients (phosphate, silicic acid, nitrate + nitrite, nitrite, ammonium), chlorophyll‐a , particulate organic carbon and nitrogen, and prokaryotes were monitored alongside dissolved manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb). Results were compared to depth profiles to evaluate the role of regeneration in trace metal cycling. In contrast to water‐column distributions, silicic acid and phosphate were closely coupled in experiments containing diatoms, indicating a shared regeneration pathway. Nitrification and nitrifying prokaryotes were only observed near the end of a subset of the experiments. Of the trace metals, Cd was most tightly coupled with phosphate. Regeneration of Mn was followed by rapid drawdown, consistent with Mn‐oxide formation. Iron (Fe), Cu, and Pb typically remained low until Mn was depleted, suggesting either scavenging to Mn‐oxides or otherwise delayed regeneration of these elements. Cobalt (Co) and Ni were largely conservative, but behaved like nutrients in the experiment using more offshore water low in Cd and Zn. Although experimental conditions were limited in their representation of the water column, these incubations provide novel insight into macronutrient and trace metal regeneration in the oceans. -
Engineered nanoparticles are incorporated into numerous emerging technologies because of their unique physical and chemical properties. Many of these properties facilitate novel interactions, including both intentional and accidental effects on biological systems. Silver-containing particles are widely used as antimicrobial agents and recent evidence indicates that bacteria rapidly become resistant to these nanoparticles. Much less studied is the chronic exposure of bacteria to particles that were not designed to interact with microorganisms. For example, previous work has demonstrated that the lithium intercalated battery cathode nanosheet, nickel manganese cobalt oxide (NMC), is cytotoxic and causes a significant delay in growth of Shewanella oneidensis MR-1 upon acute exposure. Here, we report that S. oneidensis MR-1 rapidly adapts to chronic NMC exposure and is subsequently able to survive in much higher concentrations of these particles, providing the first evidence of permanent bacterial resistance following exposure to nanoparticles that were not intended as antibacterial agents. We also found that when NMC-adapted bacteria were subjected to only the metal ions released from this material, their specific growth rates were higher than when exposed to the nanoparticle. As such, we provide here the first demonstration of bacterial resistance to complex metal oxide nanoparticles with an adaptation mechanism that cannot be fully explained by multi-metal adaptation. Importantly, this adaptation persists even after the organism has been grown in pristine media for multiple generations, indicating that S. oneidensis MR-1 has developed permanent resistance to NMC.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.2174/2666001601666211110093947
