Excess Metal Research Articles

Efficacious use of Micrococcus yunnanensis GKSM13 for the growth of rice seedlings under copper stress with elucidation into genomic traits

Rice is widely cultivated worldwide, and beneficial bactrial colonization are particularly desirable for sustainable agriculture because they promote growth and production by preventing excessive heavy metal contamination. The present study was conducted with the aim of improving the growth of rice seedlings (MTU1010 variety) under copper (Cu) stress by using Cu-tolerant plant growth promoting bacteria (PGPB) Micrococcus yunnanensis GKSM13. Strain GKSM13 was able to produce plant growth promoting factors (PGPFs) such as indole-3-acetic acid (IAA), gibberellin A3 (GA3) and ammonia, accumulate proline, fix N2, and inhibit 2,2-Diphenyl-1-picrylhydrazyl (DPPH). Rice seedlings treated with Cu2+ and co-inoculated with GKSM13 significantly improved their growth in morphological and biochemical aspects. When analysed by field emission scanning electron microscope (FE-SEM), GKSM13 was found to be associated with the root cells in the form of large number of coccoid cells. The uptake of Cu2+ in rice seedlings was reduced to 57.5% in the presence of GKSM13. Strain GKSM13 treatment also reduced Cu-induced oxidative stress of rice seedlings by activating antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX) and glutathione peroxidase (GPOX), which was supported by DPPH inhibition and reduction of malondialdehyde (MDA) accumulation. Insight into the genome of strain GKSM13 reveals the presence of tryptophan (trp), ent-kaurene, cyanase (cyn), phosphate-specific transport (pst), major facilitator superfamily transporter (MFS), sulphate transporter (cys), proline (pro) and SOD (sod) genes, which are responsible for promoting plant growth and alleviating Cu2+ stress. Therefore, the application of strain M. yunnanensis GKSM13 could provide a sustainable agricultural solution for Cu-affected mining areas.

Challenges and Breakthroughs Towards the Development and Optimisation of a Zero Excess Li-S Battery

There is currently a large demand to produce batteries and energy storage devices offering both improved volumetric and gravimetric energy densities to help prevent the catastrophic effects of climate change. One promising candidate is the lithium-sulfur (Li-S) chemistry due to the high theoretical capacity and abundance of sulfur. However, current designs require a 1000% excess of Li metal which impedes their commercialisation. An area gaining momentum is the development of “anode-free” or zero excess lithium (ZEL) cells which minimise inactive materials and mitigate the challenges of handling Li metal foils during fabrication. So far, most studies involving anode-free have been based on the Li-ion chemistry and there are significantly fewer systematic studies concerning ZEL Li-S cell fabrication and optimisation. However, nearly all fall short of targets required for commercialisation.Here we present the development of an Li2S ZEL cell composed of a Li2S/C65/SBR positive electrode material paired with a metallic current collector. The design allows for a Li-limited LiS battery where Li-ions are reversibly plated and stripped to a metallic current collector surface. We initially investigate the effects of electrolyte volume :Li2S mg (ES) ratio, conductive carbon loading, C-rate capacity dependency, various current collector materials and positive electrode substrates. The optimised cell achieves good capacity retention with a Coulombic efficiency of over 98% after 50 cycles, and a final capacity of 400 mAh g-1.Previous studies have shown difficulties in achieving consistent results and are often distorted by a large volume of conductive carbon present in the cathode substrate [1, 2]. Therefore, investigations into capacity losses stemming from the cathode are presented using a range of air-tight characterisation techniques. The performance is also closely correlated to the efficiency of reversible Li deposition onto the metallic current collector, as evaluated by comparison to the use of Li negative electrodes. In the ZEL set up, losses from dead Li formation and SEI instability result in permanent loss of Li inventory with no reservoir to replenish. To counter this, initial investigations attempting to apply an ionically conductive coating to the metal current collector surface are shown.[1]. S. Nanda, A. Gupta and A. Manthiram, Adv. Energy Mater., 2018, 8, 2–7.[2]. S. Nanda, A. Bhargav and A. Manthiram, Joule, 2020, 4, 1121–1135.

Cu Foil Modification By Ag Inkjet Printing for Improved Li Plating in Anode-Free Li Batteries

The rush in the development of new generation of lithium-ion batteries (LIB) is focused on enhancing the specific energy of batteries by employing innovative materials and manufacturing techniques. Anode-free lithium metal batteries (AFLBs) are an emerging technology that can almost double the specific energy of LIBs by eliminating the conventional graphite negative electrode or excess lithium metal 1. However, AFLBs are well-known to suffer of fast capacity decay due to the poor lithium plating and stripping efficiency process associated to the typical porous growth of Li during charge 2. Tuning the interfacial electrochemistry was widely demonstrated to be one the most performing key to enable efficient and smooth Li deposition. In this regards, functional coatings of metals as Sn, Al, Zn and Ag have been widely demonstrated to dramatically improve the quality of Li plating process respect to the neat Cu foil substrate, by forming lithium-rich alloys that provide minimum Li nucleation overpotentials 3. Inkjet printing (IJP) could be a viable technique for electrode fabrication in LIBs manufacturing, being a quick, easy and scalable technology able to deposit both thin film and patterned structures 4. However, very poor attention has been paid so far to the potentiality of IJP for Cu modification for improved Li plating in AFLBs.In this work, we employed a Fujifilm Dimatix inkjet printer to achieve “lithiophilic” coatings of Ag nanoparticles deposited on a Cu foil. In particular, potenziodynamic and galvanostatic electrochemical test were employed to investigate the effect of the Ag printed structures on the Li nucleation overpotential. Ex-situ morphological analysis by electron scanning microscopy (SEM) were usefully employed to investigate the surface evolution of the printed electrodes during lithium alloying and plating. In particular, the effect pf patterned Ag structured rather than fully coated Cu was investigated, revealing that patterning can provide more mechanically robust electrode and efficient catalytic sites for Li electrodeposition respect to fully coated inkjet printed electrodes. Bibliography L. Lin et al., Advanced Materials, 34, 2110323 (2022).L. Su and A. Manthiram, Small Structures, 3, 2200114 (2022).X. Gu, J. Dong, and C. Lai, Engineering Reports, 3, e12339 (2021).P. Viviani, E. Gibertini, F. Iervolino, M. Levi, and L. Magagnin, Journal of Manufacturing Processes, 72, 411–418 (2021).

Locally Concentrated Ionic Liquid Electrolytes for Lithium/Sulfurized Polyacrylonitrile Batteries

Low-cost sulfurized polyacrylontrile (SPAN), which shows negligible polysulfide dissolution and stable cycling up to hundreds of cycles due to a solid-phase mechanism in carbonate-based electrolytes, is a valuable high-energy cathode material for long-lifespan lithium metal batteries (LMBs).1 -3 However, the conventional carbonate-based electrolytes for commercial lithium-ion batteries are incompatible with lithium metal anodes (LMAs).4 The unstable solid-electrolyte interphases (SEIs) result in lithium dendrite growth and low lithium stripping/plating CEs, which further cause safety concerns and limited lifespan of Li/SPAN cells with low negative to positive areal capacity (N/P) ratio. Therefore, the development of Li/sulfurized polyacrylonitrile (SPAN) batteries requires electrolytes that can form stable electrolyte/electrode interphases (EEIs) simultaneously on lithium metal anodes (LMAs) and SPAN cathodes. With the remarkable compatibility toward LMAs and low flammability,4–7 locally concentrated ionic liquid electrolytes (LCILEs) might be promising candidates for Li/SPAN cells.Herein, a low-flammability locally concentrated ionic liquid electrolyte (LCILE) employing monofluorobenzene (mFBn) as the diluent is proposed for Li/SPAN cells.8 Unlike non-solvating diluents in other LCILEs, mFBn partially solvates Li+, decreasing the coordination between Li+ and bis(fluorosulfonyl)imide (FSI-). In turn, this triggers a more substantial decomposition of FSI- and consequently results in the formation of a SEI rich in inorganic compounds, which enables a remarkable Coulombic efficiency (99.72%) of LMAs. Meanwhile, a protective cathode/electrolyte interphase (CEI), derived mainly from FSI- and organic cations, is generated on the SPAN cathodes, preventing the dissolution of polysulfides. Benefiting from the robust interphases simultaneously formed on both the electrodes, highly stable cycling of Li/SPAN cells for 250 cycles with a capacity retention of 71% is achieved employing the LCILE and only 80% lithium metal excess.

Kinetics and toxicological potential of heavy metal leaching from asphalt pavements

The leaching of heavy metals from asphalt pavement has attracted increasing attention due to its associated environmental risks. Comprehending the leaching process is crucial for ensuring the safe utilization of asphalt pavement. This study investigates heavy metal leaching kinetics from asphalt pavements using tank-leaching tests and dynamic simulations employing both first and second-order kinetic models. Furthermore, this study reveals the toxicological potential of heavy metal leaching from asphalt pavement by assessing its temporal metal accessibility based on the obtained kinetic attributes. Six distinct asphalt mixtures were prepared and tested, each exhibiting two different gradations. The findings demonstrated that both kinetic models effectively elucidated the leaching process. Notably, the relatively stable final leaching stages primarily adhered to first-order kinetics, while the second-order kinetics provided a superior description of the more intricate initial leaching stages. In terms of toxicological potential, the results indicated that recycled waste-incorporated asphalt pavements, specifically bottom ash-incorporated asphalt and asphalt rubber, exhibited excessive heavy metal leaching for varying durations, ranging from several days to months under specific conditions. This study has provided valuable insights into the metal leaching kinetics of asphalt pavements and their associated toxicological impact, significantly advancing the current understanding of the consequences of heavy metal leaching from asphalt pavements.

Combined passivators regulate physiological, antioxidant potential and metals accumulation in potato grown in metals contaminated soil

To solve the problem of excessive heavy metals in farmland soil, there is a dire need for research effort to screen for the soil passivator materials. This study aimed to develop a practical novel approach for improving the potato growth and remedial effectiveness of the metals by optimal combination and dosage of various passivators. Experimental treatments were comprised of various levels of passivating agents (sepiolite, quicklime and calcium magnesium phosphate) in individual and combined form. Results showed that application of passivating agents significantly enhanced growth by optimizing photosynthetic attributes, enzymatic antioxidants, and soil health. Balanced application of passivators effectively reduce the bioavailability of metals, curbing their uptake by potato plants. Sole application of all the agents results statistically similar outcomes as compared with combined form. Additionally, passivators indirectly enhance the activity of essential antioxidant enzymes. Synergistic effect of all the agents significantly improved the tuber quality by decreasing the accumulation of proline, malondialdehyde content, and bioaccumulation of Cu, Pb, Cd, and As in potato parts. In crux, combined usage of passivating agents proved to be of better growth, improvement in antioxidative defense system, and better quality of potato. By mitigating heavy metal contamination, passivators not only enhance crop quality and yield but also ensure heavy metal-free potatoes that meet stringent food safety standards.

Post-synthesis metal (Sn, Zr, Hf) modification of BEA zeolite: Combined Lewis and Br⊘nsted acidity for cascade catalysis

Zeolites modified by Lewis acidic metal centers such as Sn, Zr, and Hf are promising catalysts for numerous reactions relevant to biorefining, such as isomerization of carbohydrates and Meerwein-Ponndorf-Verley (MPV) reduction of furans. Preferred catalysts contain these metal ions in the framework of large-pore BEA zeolite, requiring often complex multistep preparation procedures based on expensive organometallic precursors. Herein, we developed a facile approach for obtaining highly dispersed isolated Sn, Zr, and Hf incorporated in dealuminated BEA zeolite with high metal content (Si/M ratio of 50–75) via a solid-state grinding approach using simple inorganic metal precursors. The efficient incorporation of isolated metal sites in the BEA framework with high content was achieved by methanol treatment before calcination, which removes excess metal. The Lewis acid sites derive from isolated metal ions in open sites for Sn, Zr, and Hf, while Sn-modified BEA also contains closed Sn sites. The open Sn sites display the highest Lewis acidity. The Br⊘nsted acidity stems from silanols perturbed by Lewis acidic metal ions of open metal sites and the OH group connected to the open metal sites. The metal-modified zeolites are active in the cascade reductive etherification of cinnamaldehyde, involving the MPV reduction to cinnamyl alcohol and the subsequent etherification to cinnamyl propyl ether with the isopropanol solvent over Lewis and Br⊘nsted acid sites, respectively. Sn-modified BEA was the most active sample, which stems from its strongest Lewis acidity, which is crucial for the first MPV step. Sn modification of the optimized solid-state ion-exchange method was applied to various BEA zeolites with different morphologies (nanocrystalline, hierarchical, and conventional BEA), showing that pore hierarchization can further benefit cascade reductive etherification reaction.

Pemanfaatan Eceng Gondok sebagai Adsorben dengan Perlakuan Awal untuk Menurunkan Kadar Logam Berat Cu

Industri kimia yang dalam prosesnya menggunakan katalis tembaga ataupun garam tembaga biasanya dalam limbah yang dibuang ke lingkungan juga akan terikut logam berat tembaga (Cu). Mengingat bahaya yang ditimbulkan oleh logam berat tembaga, maka dilakukan upaya untuk mengurangi kadar limbah tembaga di perairan. Salah satu metode yang dapat mengatasi kelebihan logam Cu adalah dengan proses adsorpsi. Proses adsorpsi memiliki banyak keuntungan, diantaranya dalam pengadaan media lebih ekonomis dan tidak men-imbulkan efek samping yang beracun. Tanaman Eceng gondok merupakan tanaman yang memiliki kandungan karbon cukup tinggi, sehingga tanaman eceng gondok berpotensi untuk dijadikan bahan baku pembuatan karbon aktif. Penelitian ini akan memeplejarari pembuatan eceng godondok sebagai karbon aktif. Proses dalam pembu-atan karbon aktif diawali dengan memasak eceng gondok dengan larutan NaOH untuk meningkatkan jumlah selulosa sebagai bahan utama pembutan karbon aktif. Kemudian eceng gondok dikeringkan dan dijadikan ser-buk. Selanjutnya serbuk eceng gondok diaktivasi dengan HCl. Proses uji adsorben dilakukan dengan menam-bahkan karbon aktif pada larutan CuSO4 dengan variabel konsentrasi 2 M, 2.4M, 2.8 M, 3.2 M, 3.6 M dan waktu pengontakkan 25, 35, 50, 65, 80 menit. Hasil analisa dari metode spektrofotometri serapan atom (AAS) bahwa semakin besar konsentrasi dan waktu pengontakan maka semakin tinggi effesiensi penyerapan karbon konsentrasi aktivator 3,6 M dengan waktu pengontakan 80 menit sehingga effesiensi penyerapan Cu sebesar 42,892 %.

Characterization of genes involved in micronutrients and toxic metals detoxification in Brassica napus by genome-wide cDNA library screening.

Stresses caused by deficiency/excess of mineral nutrients or of pollution of toxic metals have already become a primary factor in limiting crop production worldwide. Genes involved in minerals and toxic metals accumulation/tolerance could be potential candidates for improving crop plants with enhanced nutritional efficiency and environmental adaptability. In this study, we first generated a high-quality yeast expression cDNA library of Brassica napus (Westar), and 46 genes mediating excess micronutrients and toxic metals detoxification were screened using the yeast genetic complementation system, including 11, 5, 6, 14, 6, and 5 genes involved in cadmium (Cd), zinc (Zn), iron (Fe), manganese (Mn), boron (B), and copper (Cu) tolerance, respectively. Characterization of genes mediating excess ions stress resistance in this study is beneficial for us to further understand ions homeostasis in B. napus.

Simultaneous realization of heavy metal Cd solidification and chloride separation in municipal solid waste incineration fly ash: Mechanism and DFT analysis

The solidification of heavy metals and the separation-recycling of chloride salts are effective approaches for the safe disposal of municipal solid waste incineration (MSWI) fly ash. This study achieved the solidification of the excessive heavy metal Cd by transforming MSWI fly ash into a solidified body mainly composed of ettringite, while also purifying the calcium and sulfate ions in the chloride solution. The research results demonstrate that the introduction of aluminum ions rapidly decreases the pH value of the MSWI fly ash reaction system. By adjusting the reaction system to a pH value of 11.50, the conversion rate of calcium ions reaches 99.68%, the separation rate of chloride reaches 95.99%, and the solidification rate of heavy metal Cd reaches 98.92%. Density functional theory (DFT) calculations indicate that the vacancy formation at the Ca-2 position of ettringite and Cd entering the vacancy has a higher probability. The combination of DFT calculations and experiments validates that heavy metal Cd leads to charge redistribution, increased interplanar spacing, and decreased thermal stability of ettringite. The concentration of calcium ions in the solution decreases to 22.64 mg/L, achieving efficient recovery of sodium chloride and potassium chloride in a shorter process. The ettringite-based solidified body contains 0.87% chloride ions, showing potential for resource utilization in cement-based materials.

Different Source Contributions of Bioactive Trace Metals in Sinking Particles in the Northern South China Sea

Time-series samples intercepted via three synchronized moored sediment traps, deployed at 1000 m, 2150 m, and 3200 m in the northern South China Sea (NSCS) during June 2009–May 2010, were analyzed to quantify the bioactive trace metal fluxes in sinking particles and investigate their different source contributions. Iron (Fe) primarily originated from lithogenic sources. Manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn) exhibited various degrees of enrichment over their continental crustal ratios. Since the sources of bioactive trace metals in sinking particles can be divided into lithogenic, biogenic, and excess fractions, mass conservation calculations were used to quantify the contribution of each source. The results showed that Fe, Mn, and Co had extremely low biogenic proportions (0.1–3.3%), while Ni, Cu, and Zn had higher proportions (2.7–17.3%), with the biogenic fraction decreasing with the depth. Moreover, excess sources accounted for a significant proportion of Mn (68–75%), Co (34–54%), Ni (60–62%), Cu (59–74%), and Zn (56–65%) in sinking particles at the three sampling depths. The excess fractions of Mn, Co, and Cu in sinking particles can be affected by authigenic particles. This is supported by their similar scavenging-type behavior, as observed via the increase in their fluxes and enrichment patterns with the increasing depth. Furthermore, the excess fractions of Ni, Cu, and Zn may have significant contributions from anthropogenic sources. The variability of Fe in sinking particles was mainly controlled via lithogenic matter. Notably, organic matter and opal were found to be pivotal carriers in the export of excess bioactive trace metals (Mn, Co, Ni, and Cu) via the water column, accompanied with the elevated ballast effect of lithogenic matter with the depth. However, the transportation of excess Zn was more complicated due to the intricate processes involved in Zn dynamics. These findings contribute to our understanding of the sources and transport mechanisms of bioactive trace metals in the marine environment.

Migration pathway and solidification mechanism of heavy metal Pb during the conversion of municipal solid waste incineration fly ash into ettringite and simultaneously purification of chloride salts solution process

The solidification/stabilization of heavy metals and valuable component recovery from municipal solid waste incineration (MSWI) fly ash are of great significance for its safe disposal. In this study, MSWI fly ash was transformed into a new solid phase mainly composed of ettringite, achieving the solidification of excessive heavy metal Pb while obtaining a mixed solution of sodium chloride and potassium chloride with extremely low impurity content, which can be recovered by evaporation-crystallization respectively. The solidification mechanism of heavy metal Pb by ettringite was investigated through a combination of DFT calculations and experiments. The results indicate that a high conversion rate of calcium ions (99.68%), separation rate of chloride (95.99%), and conversion rate of heavy metal Pb (99.42%) can be achieved by controlling the ions ratio of the MSWI fly ash reaction system to n(Ca2+):n(Al3+):n(SO42−) = 6:2:3. DFT calculations show that the reaction pathway of the formation of a vacancy-Pb entering the vacancy at the Ca-2 site of ettringite is more likely to occur. The substitution of heavy metal Pb at the Ca-2 site leads to an increase in the unit cell volume, redistribution of charges, and a decrease in the thermal stability of the ettringite. The solidified body of ettringite presents a promising potential for application in cement-based materials due to its negligible risk of heavy metals leaching and low chloride content.

Rational design of hierarchically-solvating electrolytes enabling highly stable lithium metal batteries with high-nickel cathodes

The practical implementation of lithium-metal anodes in high-energy-density batteries with high-nickel cathodes requires the electrolytes that prevent dendrite growth, enable high rate performance, and provide adequate cathodic stability. Traditional electrolytes, however, struggle to fulfill these requirements, and a universal electrolyte design rule remains lacking. Herein, we introduce a hybrid strongly-weakly-solvating solvent (HSWSS) rule, based on Raman shifts and dielectric constants of solvents, to rationally design a multi-component hierarchically-solvating electrolyte (HSE) with a wide electrochemical window (>4.45 V), decent ionic conductivity (4.28 mS cm−1), and dendrite suppression ability. By introducing strongly-solvating cosolvent and appropriate Li salts into weakly solvating solvent, the HSE enable the Li||LiNi0.8Co0.1Mn0.1O2 cell (1.8 mAh cm−2, with 3 times excess ultrathin Li metal) to exhibit a high capacity retention of 74.3 % after 150 cycles at 1 C with a remarkable high Coulombic efficiency of 99.60 %. HSEs can also be conveniently prepared using commercially available solvents and salts, making them practical and cost effective for large-scale lithium-metal battery manufacturing. As a result, this rational design offers a new direction for the development of advanced electrolytes in high-energy-density lithium-metal batteries.

Long-term operation optimization of circulating cooling water systems under fouling conditions

Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating water system (CCWS) by depositing ions on the heat exchanger's surface. Currently, the operation optimization of CCWS often prioritizes short-term flow velocity optimization for minimizing power consumption, without considering fouling. However, low flow velocity promotes fouling. Therefore, it’s crucial to balance fouling and energy/water conservation for optimal CCWS long-term operation. This study proposes a mixed-integer nonlinear programming (MINLP) model to achieve this goal. The model considers fouling in the pipeline, dynamic concentration cycle, and variable frequency drive to optimize the synergy between heat transfer, pressure drop, and fouling. By optimizing the concentration cycle of the CCWS, water conservation and fouling control can be achieved. The model can obtain the optimal operating parameters for different operation intervals, including the number of pumps, frequency, and valve local resistance coefficient. Sensitivity experiments on cycle and environmental temperature reveal that as the cycle increases, the marginal benefits of energy/water conservation decrease. In periods with minimal impact on fouling rate, energy/water conservation can be achieved by increasing the cycle while maintaining a low fouling rate. Overall, the proposed model has significant energy/water saving effects and can comprehensively optimize the CCWS through its incorporation of fouling and cycle optimization.

Effects of metal amendment and metalloid supplementation on foliar defences are plant accession-specific in the hyperaccumulator Arabidopsis halleri.

Soil pollution by metals and metalloids as a consequence of anthropogenic industrialisation exerts a seriously damaging impact on ecosystems. However, certain plant species, termed hyperaccumulators, are able to accumulate extraordinarily high concentrations of these metal(loid)s in their aboveground tissues. Such hyperaccumulation of metal(loid)s is known to act as a defence against various antagonists, such as herbivores and pathogens. We investigated the influences of metal(loid)s on potential defence traits, such as foliar elemental, organic and mechanical defences, in the hyperaccumulator plant species Arabidopsis halleri (Brassicaceae) by artificially amending the soil with common metallic pollutants, namely cadmium (Cd) and zinc (Zn). Additionally, unamended and metal-amended soils were supplemented with the metalloid silicon (Si) to study whether Si could alleviate metal excess. Individuals originating from one non-/low- and two moderately to highly metal-contaminated sites with different metal concentrations (hereafter called accessions) were grown for eight weeks in a full-factorial design under standardised conditions. There were significant interactive effects of metal amendment and Si supplementation on foliar concentrations of certain elements (Zn, Si, aluminium (Al), iron (Fe), potassium (K) and sulfur (S), but these were accession-specific. Profiles of glucosinolates, characteristic organic defences of Brassicaceae, were distinct among accessions, and the composition was affected by soil metal amendment. Moreover, plants grown on metal-amended soil contained lower concentrations of total glucosinolates in one of the accessions, which suggests a potential trade-off between inorganic defence acquisition and biosynthesis of organic defence. The density of foliar trichomes, as a proxy for the first layer of mechanical defence, was also influenced by metal amendment and/or Si supplementation in an accession-dependent manner. Our study highlights the importance of examining the effects of co-occurring metal(loid)s in soil on various foliar defence traits in different accessions of a hyperaccumulating species.

Fabricating lithiophilic Sn nanolayer via vacuum evaporation coating for anode-free lithium metal battery

Lithium metal batteries (LMBs) have great advantages such like high energy density and capacity and low cost, which are widely studied by many researchers. As a type of LMBs, anode-free LMBs have zero Li excess, i.e., the entire Li is stripped from the cathode or current collector, obviously reducing the waste of excessive Li metal and improving the energy density of battery. However, the uneven deposition of Li will lead to the growth of Li dendrites, which reduces the columbic efficiency and cycling life of anode-free LMBs. In this work, the vacuum evaporation coating is used to synthesize a lithiophilic Sn nanolayer on Cu substrate, providing uniform deposition sites for Li. The polarization of Li deposition is reduced and the cyclability of anode-free LMBs is improved. As a result, a stable cycling performance for over 200 h at 3 mA cm−2 under 1 mAh cm−2 is achieved, demonstrating the superior Li-deposition regulation effect of Sn nanolayer.

Factors influencing the detergent-free membrane protein isolation using synthetic nanodisc-forming polymers

The detergent-free isolation of membrane proteins using synthetic polymers is becoming the desired approach for functional and structural studies of membrane proteins. Since the expression levels for many membrane proteins are low and a high yield of functionalized reconstituted membrane proteins is essential for in vitro studies, it is crucial to optimize the experimental conditions for a given polymer to solubilize target membranes/proteins effectively. The factors that affect membrane solubilization and subsequently the isolation of a target membrane protein include polymer concentration, polymer charge, temperature, pH, and concentration of divalent metal ions. Therefore, it is important to have knowledge about the efficacy of different types of polymers in solubilizing cell membranes. In this study, we evaluate the efficacy of inulin-based non-ionic polymers in solubilizing E. coli membranes enriched with rat flavin mononucleotide binding-domain (FBD) of cytochrome-P450-reductase (CPR) and rabbit cytochrome-b5 (Cyt-b5) under various solubilization conditions. Our results show that a 1:1 (w/w) membrane:polymer ratio, low temperature, high pH and sub-millimolar concentration of metal ions favor the solubilization of E. coli membranes enriched with FBD or Cyt-b5. Conversely, the presence of excess divalent metal ions affected the final protein levels in the polymer-solubilized samples. We believe that the results from this study provide knowledge to assess and plan the use of non-ionic polymers in membrane protein studies.

Overcoming Challenges: Extending Cycle Life of Aqueous Zinc-Ion Batteries at High Zinc Utilization through a Synergistic Strategy.

Aqueous zinc-ion batteries (AZIBs) face challenges in achieving high energy density compared to conventional lithium-ion batteries (LIBs). The lower operating voltage and excessive Zn metal as anode pose constraints on the overall energy storage capacity of these batteries. An effective approach is to reduce the thickness of the Zn metal anode and control its mass appropriately. However, under the condition of using a thin Zn anode, the performance of AZIBs is often unsatisfactory. Through experiments and computational simulations, the electrode structural change and the formation of dead Zn as the primary reasons for the failure of batteries under a high Zn utilization rate are identified. Based on this understanding, a universal synergistic strategy that combines Cu foil current collectors and electrolyte additives to maintain the structural and thermodynamic stability of the Zn anode under a high Zn utilization rate (ZUR) is proposed. Specifically, the Cu current collectors can ensure that the Zn anode structure remains intact based on the spontaneous filling effect, while the additives can suppress parasitic side reactions at the interface. Ultimately, the symmetric cell demonstrates a cycling duration of 900 h at a 70% ZU, confirming the effectiveness of this strategy.

Highly selective adsorbents based on silica gel chemically modified with sulfur-containing groups of arched structure for preconcentration and determination of palladium(II) in products of processing of sulfide copper-nickel ore

Adsorbents based on silica gel chemically modified with arch structure 2-aminophenyl disulfide (DSS) and bis[3-(triethoxysilyl)propyl]tetrasulfide (TSS) groups have been synthesized. The proposed adsorbents quantitatively extracted (extraction ∼99 %) only palladium(II) among all platinum metals from solutions of 2 M HCl - pH 4. Quantitative extraction of Pd(II) was not interfered with 106-fold excesses of alkaline, alkaline-earth, 104-fold excesses of non-ferrous metals and iron, 102-103-fold excesses of other platinum metals. Pd(II) was eluted quantitatively (desorption ∼99 %) from the adsorbents surface with 5–10 % thiourea solutions and could be determined in the eluate by inductively coupled plasma optical emission spectrometry (ICP-OES). The adsorption capacity of DSS and TSS adsorbents was not changed after 5 adsorption-elution cycles. The limit of detection of palladium in the analyzed solution, calculated using the 3 s-criterion, was 0.1 μg/L for solid-phase extraction-inductively coupled plasma optical emission spectrometry (SPE-ICP-OES) method with a preconcentration factor of 50. Intensive yellow-orange color of the palladium surface complex was used in the development of express test-methods for its determination. SPE-ICP-OES and test methods were used in the determination of palladium in certified reference materials of sulfide copper-nickel ore and products of its technological processing.

Comparative Assessment of Heavy Metal Concentration in Some Edible Spinach (Amaranthus hybridus) in Southern Taraba (Ibi, Wukari and Donga), Nigeria

This study focuses on the assessment and comparative concentrations of some heavy metals in spinach (Amaranthus hybridus), cultivated in Wukari, Ibi, Donga local government area of Taraba State in Nigeria. The research is motivated by the indiscriminate use of bulk chemicals for farming activities in the communities under review. The study employed random sampling techniques in collecting the samples of the spinach. The edible part were digested and analyzed for the following heavy metal content: Lead, Zinc, Copper, Nickel, Iron, Cobalt, Chromium, Manganese, and Cadmium. The Atomic Absorption Spectroscopy (AAS) technique was used to analyze the samples. The results for the main concentration of heavy metal were revealed. The concentration of heavy metals in the spinach obtained from the three different samples varies. It was observed that, the sample obtained from Wukari has the highest accumulation of heavy metals. The concentrations of Pb, Mn and Cr were found to be higher than the permissible limits in Wukari spinach. Cd was not detected in the three (Ibi, Donga and Wukari). Pb was not detected in Ibi and Donga. Cu and Ni were not detected in Donga. Based on the findings from this study, spinach from Ibi and Donga are recommended for consumption compared to Wukari, since most of the heavy metals in this study areas are within the standard permissible limit set by WHO/FAO. Similarly, the daily intake of heavy metal (DIM) and the health risk index (HRI) analysis from the 3 study areas also falls within the acceptable permissible level. Farmers and consumers should be adviced appropriately on the health implications of excessive heavy metal consumption in vegetables.