Metal Solution Research Articles

Knudsen effusion mass spectrometry: Current and future approaches.

Knudsen effusion mass spectrometry (KEMS) has been a powerful tool in physical chemistry since 1954. There are many excellent reviews of the basic principles of KEMS in the literature. In this review, we focus on the current status and potential growth areas for this instrumental technique. We discuss (1) instrumentation, (2) measurement techniques, and (3) selected novel applications of the technique. Improved heating methods and temperature measurement allow for better control of the Knudsen cell effusive source. Accurate computer models of the effusive beam and its introduction to the ionizer allow optimization of such parameters as sensitivity and removal of background signals. Computer models of the ionizer allow for optimized sensitivity and resolution. Additionally, data acquisition systems specifically tailored to a KEMS system permit improved quantity and quality of data. KEMS is traditionally utilized for thermodynamic measurements of pure compounds and solutions. These measurements can now be strengthened using first principles and model-based computational thermochemistry. First principles can be used to calculate accurate Gibbs energy functions (gefs) for improving third law calculations. Calculated enthalpies of formation and dissociation energies from ab initio methods can be compared to those measured using KEMS. For model-based thermochemistry, solution parameters can be derived from measured thermochemical data on metallic and nonmetallic solutions. Beyond thermodynamic measurements, KEMS has been used for many specific applications. We select examples for discussion: measurements of phase changes, measurement/control of low-oxygen potential systems, thermochemistry of ultrahigh-temperature ceramics, geological applications, nuclear applications, applications to organic and organometallic compounds, and thermochemistry of functional room temperature materials, such as lithium ion batteries. We present an overview of the current status of KEMS and discuss ideas for improving KEMS instrumentation and measurements. We discuss selected KEMS studies to illustrate future directions of KEMS.

Performance of Teflon- reinforced Nafion against microbes and removal of heavy metal ions from aqueous environment

Considering its promising antimicrobial and metal removal capabilities, water filtration systems have not yet widely used ionic polymer membranes. A textile structure made of Nafion polymer reinforced with Teflon (TFRN) was coated with non-precious metals copper and silver using a chemical decomposition technique. Scanning electron microscopy makes it quite evident that a surface coating was formed with evenly distributed metal particles. Water and moisture uptake capacity for Silver (Ag)-Copper (Cu) coated membrane was reduced by 80 and 67 % respectively compared to pure membrane. Inaddition, Ag–Cu coated membrane showed best performance against Escherichia coli (ATCC25922), and Staphylococcus aureus (ATCC 25923) with 2.04 and 1.7 CFU/ml respectively, by considering below level of Quantification as 1.6 CFU/ml. Pure Nafion membrane at pH 6.5, was used to perform the adsorption studies of transition metal ions like Copper, Nickel, Chromium, Barium, Tin and Arsenic at room temperature. The maximum metal ion removal was about 35 % for Copper followed by Nickel (31 %) and the least adsorption was observed for Barium (13.5 %) from multi-heavy metals solution. The study revealed that the potential of TFRN membrane for water purification in terms of metal and microbial removal process.

Unlocking the potential of biochar: an iron-phosphorus-based composite modified adsorbent for adsorption of Pb(II) and Cd(II) in aqueous environments and response surface optimization of adsorption conditions.

In this work, iron-phosphorus based composite biochar (FPBC) was prepared by modification with potassium phosphate and iron oxides for the removal of heavy metal ions from single and mixed heavy metal (Pb and Cd) solutions. FTIR and XPS characterization experiments showed that the novel modified biochar had a greater number of surface functional groups compared to the pristine biochar. The maximum adsorption capacities of FPBC for Pb(II) and Cd(II) were 211.66mg·g-1 and 94.08mg·g-1 at 293K. The adsorption of Pb(II) and Cd(II) by FPBC followed the proposed two-step adsorption kinetic model and the Freundlich isothermal adsorption model, suggesting that the mechanism of adsorption of Pb(II) and Cd(II) by FPBC involved chemical adsorption of multiple layers. Mechanistic studies showed that the introduction of -PO4 and -PO3 chemisorbed with Pb(II) and Cd(II), and the introduction of -Fe-O increased the ion exchange with Pb(II) and Cd(II) during the adsorption process and produced precipitates such as Pb3Fe(PO4)3 and Cd5Fe2(P2O7)4. Additionally, the abundant -OH and -COOH groups also participated in the removal of Pb(II) and Cd(II). In addition, FPBC demonstrated strong selective adsorption of Pb(II) in mixed heavy metal solutions. The Response Surface Methodology(RSM) analysis determined the optimal adsorption conditions for FPBC as pH 5.31, temperature 26.01°C, and Pb(II) concentration 306.30mg·L-1 for Pb(II). Similarly, the optimal adsorption conditions for Cd(II) were found to be pH 5.66, temperature 39.34°C, and Cd(II) concentration 267.68mg·L-1. Therefore, FPBC has the potential for application as a composite-modified adsorbent for the adsorption of multiple heavy metal ions.

Design of Ni-based amorphous alloy corrosion-resistant to high temperature hydrochloric acid

A corrosion-resistant Ni-based amorphous alloy was developed by combining the Inoue’s three principles and the dissolution-ionization-diffusion-deposition (DIDD) model. The calculations showed that a rapid localized increase of pH value at the metal-solution (M-S) interface is due to the dissolution of both Ta and Nb in the Ni-Nb-Ta-Fe-P alloy system and is beneficial to the formation of two-layered structure of corrosion inhibition in the passivation film, in which the dense Ta/Nb mixed oxides formed initially in the passivation film while the extra mixed-phosphates appeared in the inner layer neighboring the substrate. The 140 d immersion experiment in the 80 ℃/32 wt% hydrochloric acid and the electrochemical testing showed that the (Ni57.5Nb19.5P8Fe14.9)87Ta13 amorphous alloy had the lowest corrosion rate together with the best resistance to the metastable pitting. The structure of passivation film was mainly composed of dense Ta-Nb mixed oxides with an inner phosphate layer, which was consistent with the theoretical calculations. The work indicated that the DIDD model could be useful in designing Ni-based amorphous alloys for extremely corrosive service environments.

Determination of Binding Constants for the Complexes Between Heavy Metal Ions and Cucurbit[n]uril

AbstractOne of the major concerns worldwide is the rapid increase in water pollution with hazardous heavy metals. The Cucurbit[n]uril (CB[n]) structure provides an inner hydrophobic cavity accessible through two electrostatically negative portals with polar carbonyl groups, allowing for charged ion–dipole interaction between cationic species with excellent binding affinities. In this work we selected CB[5], and CB[7] for the titrimetric and electrochemical evaluation of the heavy metal complexes formed with Copper(II), Cadmium(II) and Lead(II). The host–guest interaction was found by either attenuation of the redox peaks, the formation of a new peak, or the slight shift in the redox peaks of the heavy metal ions. Titration data were obtained for CB[n] with the heavy metal solutions to determine the molar coefficient of binding. The stoichiometry of the complexes was 1 : 1 by Job′s plot. We calculated the binding constants using the Benesi–Hildebrand method achieving relatively good binding constants (K) ranging from (1.80±0.14)×105–(4.98±0.13)×105 M−1. The results showed that the complexes of Cadmium(II) and Lead(II) with both CB[5] and CB[7] are highly stable in aqueous media. Copper(II) was able to bind to the smaller sized portal of CB[5], whereas with CB[7] the heavy metal ion could not form a favourable complex. This phenomenon suggests that the CB[5] is an ideal host at forming stable host–guest interactions than their larger homologue.

Phosphorus‐based anodes for fast‐charging alkali metal ion batteries

AbstractAdvancing fast‐charging technology is an important strategy for the development of alkali metal ion batteries (AMIBs). The exploitation of a new generation of anode material system with high‐rate performance, high capacity, and low risk of lithium/sodium/potassium plating is critical to realize fast‐charging capability of AMIBs while maintaining high energy density and safety. Among them, phosphorus‐based anodes including phosphorus anodes and metal phosphide anodes have attracted wide attention, due to their high theoretical capacities, safe reaction voltages, and natural abundance. In this review, we summarize the research progress of different phosphorus‐based anodes for fast‐charging AMIBs, including material properties, mechanisms for storing alkali metal ions, key challenges and solution strategies for achieving fast‐charging capability. Moreover, the future development directions of phosphorus‐based anodes in fast‐charging AMIBs are highlighted.image

On the Development of an Open-Source Toolbox for the Structural Analysis of Composite Materials

Commonly used in structural applications since the ’90s, composite materials represent a valid alternative to metallic solutions. An intense research activity accompanied the spread of this technology to the point that, nowadays, a large variety of modeling techniques and tools are at the designers’ disposal. Although the literature on this topic is vast, detailed, and thorough, the need for new, faster, and more efficient design tools and methodologies remains. In this context, this work covers the development of an Open-Source computational laminate analysis toolbox, its structure, and its validation. The objective of the research was the creation of a simple and accessible mean for the calculation of laminates’ stresses in complex structural components with a reduced computational cost. To this end, the authors implemented the basics of micro, meso, and micromechanics in a Python-based toolbox and then performed a validation campaign against the results of an FE analysis. The work resulted in an input-generation/output-analysis instrument to be used by designers alongside the FEA.

Structural Evolution of GaOx-Shell and Intermetallic Phases in Ga-Pt Supported Catalytically Active Liquid Metal Solutions.

We present a comprehensive scale-bridging characterization approach for supported catalytically active liquid metal solutions (SCALMS) which combines lab-based X-ray microscopy, nano X-ray computed tomography (nano-CT), and correlative analytical transmission electron microscopy. SCALMS catalysts consist of low-melting alloy particles and have demonstrated high catalytic activity, selectivity, and long-term stability in propane dehydrogenation (PDH). We established an identical-location nano-CT workflow which allows us to reveal site-specific changes of Ga-Pt SCALMS before and after PDH. These observations are complemented by analytical transmission electron microscopy investigations providing information on the structure, chemical composition, and phase distribution of individual SCALMS particles. Key findings of this combined microscopic approach include (i) structural evolution of the SCALMS particles' GaOx shell, (ii) Pt segregation toward the oxide shell leading to the formation of Ga-Pt intermetallic phases, and (iii) cracking of the oxide shell accompanied by the release of liquid Ga-Pt toward the porous support.

Dosing of OH– ions from acrylamide hydrogels for the selective precipitation of copper/cobalt ions in aqueous solutions

The recovery of heavy metals in contaminated water has focused on the adsorption of metal ions by different materials, ranging from artificial and natural zeolites, activated carbon, and some hydrogels. Although successful in removing metal ions, these methods possess the disadvantage of absorbing all ions within the solution. In the present work, acrylamide hydrogels were used as storers and dispensers of OH– ions to aqueous solutions containing cobalt and copper ions to carry promising the precipitation reaction of the metal hydroxides and to determine the selectivity in the precipitation of copper hydroxide or cobalt hydroxide, depending on the ratio of a hydrogel loaded with OH– ions and the mass of the metal solution, varying the ratio of cobalt/copper in the aqueous solution.

First-principles study of the interaction of nitrogen with transition metal solutes in tungsten

The choice of tungsten (W) as the plasma-facing material requires seeding impurities into the edge plasma for radiative cooling, and gaseous nitrogen (N) is one of the most likely impurities to be used for this purpose. In this work, first-principles calculations related to the interactions between N and transition metal (TM) solutes were performed. The interactions between the TM solutes and N are predominantly attractive and very localized. Specifically, the 3d solutes exhibit a stronger attraction to N than the 4d and 5d solutes. Consequently, most TM solutes can alter the N distribution, promoting the N aggregation within their neighboring shells, and impeding the N diffusion. Moreover, this effect is more conspicuous in the 3d solutes related to the 4d and 5d solutes. In the Sol-Vac-N complexes, the vacancy assumes a predominant role. Most TM solutes diminish the capability of vacancies to capture N. The exception arises in Ti, V, Zr, Nb, Hf, and Ta, where these solutes enhance the vacancies' ability to capture N. Further investigation revealed that, for Ti, V, Zr, Hf, Ta, and Os, the capacity of Sol-N pairs to adsorb the additional N and solute atoms is significant. As a result, it can be speculated that the Sol-N pairs for these solutes might continue to adsorb additional N and solute atoms, eventually evolving into nitrides. However, for the primary transmutation product Re, the capacity of Sol-N pairs to adsorb additional Re atoms is negligible. Therefore, it is inferred that the formation of Re nitride is rather unlikely during W's service life as plasma-facing materials.

Impact of Catalysis-Relevant Oxidation and Annealing Treatments on Nanostructured GaRh Alloys.

In this study, we examine the surface-derived electronic and chemical structures of nanostructured GaRh alloys as a model system for supported catalytically active liquid metal solutions (SCALMS), a novel catalyst candidate for dehydrogenation reactions that are important for the petrochemical and hydrogen energy industry. It is reported that under ambient conditions, SCALMS tends to form a gallium oxide shell, which can be removed by an activation treatment at elevated temperatures and hydrogen flow to enhance the catalytic reactivity. We prepared a 7 at. % Rh containing the GaRh sample and interrogated the evolution of the surface chemical and electronic structure by photoelectron spectroscopy (complemented by scanning electron microscopy) upon performing surface oxidation and (activation treatment mimicking) annealing treatments in ultrahigh vacuum conditions. The initially pronounced Rh 4d and Fermi level-derived states in the valence band spectra disappear upon oxidation (due to formation of a GaOx shell) but reemerge upon annealing, especially for temperatures of 600 °C and above, i.e., when the GaOx shell is efficiently being removed and the Ga matrix is expected to be liquid. At the same temperature, new spectroscopic features at both the high and low binding energy sides of the Rh 3d5/2 spectra are observed, which we attribute to new GaRh species with depleted and enriched Rh contents, respectively. A liquefied and GaOx-free surface is also expected for GaRh SCALMS at reaction conditions, and thus the revealed high-temperature properties of the GaRh alloy provide insights about respective catalysts at work.

Mechanism behind the Controlled Generation of Liquid Metal Nanoparticles by Mechanical Agitation.

The size-controlled synthesis of liquid metal nanoparticles is necessary in a variety of applications. Sonication is a common method for breaking down bulk liquid metals into small particles, yet the influence of critical factors such as liquid metal composition has remained elusive. Our study employs high-speed imaging to unravel the mechanism of liquid metal particle formation during mechanical agitation. Gallium-based liquid metals, with and without secondary metals of bismuth, indium, and tin, are analyzed to observe the effect of cavitation and surface eruption during sonication and particle release. The impact of the secondary metal inclusion is investigated on liquid metals' surface tension, solution turbidity, and size distribution of the generated particles. Our work evidences that there is an inverse relationship between the surface tension and the ability of liquid metals to be broken down by sonication. We show that even for 0.22 at. % of bismuth in gallium, the surface tension is significantly decreased from 558 to 417 mN/m (measured in Milli-Q water), resulting in an enhanced particle generation rate: 3.6 times increase in turbidity and ∼43% reduction in the size of particles for bismuth in gallium liquid alloy compared to liquid gallium for the same sonication duration. The effect of particles' size on the photocatalysis of the annealed particles is also presented to show the applicability of the process in a proof-of-concept demonstration. This work contributes to a broader understanding of the synthesis of nanoparticles, with controlled size and characteristics, via mechanical agitation of liquid metals for diverse applications.

Optimization of CO fermentation by Clostridium carboxidivorans in batch reactors: Effects of the medium composition

ObjectivesThe objective of this study was to investigate the effects of medium composition on CO fermentation by Clostridium carboxidivorans. The focus was to reduce the medium cost preserving acceptable levels of solvent production. MethodsYeast extract (YE) concentration was set in the range of 0–3 g/L. Different reducing agents were investigated, including cysteine-HCl 0.6 g/L, pure cysteine 0.6 g/L, sodium sulphide (Na2S) 0.6 g/L, cysteine-sodium sulphide 0.6 g/L and cysteine-sodium sulphide 0.72 g/L. The concentration of the metal solution was decreased down to 25 % of the standard value. Fermentation tests were also carried out with and without tungsten or selenium. ResultsThe results demonstrated that under optimized conditions, namely yeast extract (YE) concentration set at 1 g/L, pure cysteine as the reducing agent and trace metal concentration reduced to 75 % of the standard value, reasonable solvent production was achieved in less than 150 h. Under these operating conditions, the production levels were found to be 1.39 g/L of ethanol and 0.27 g/L of butanol. Furthermore, the study revealed that selenium was not necessary for C. carboxidivorans fermentation, whereas the presence of tungsten played a crucial role in both cell growth and solvent production. ConclusionsThe optimization of the medium composition in CO fermentation by Clostridium carboxidivorans is crucial for cost-effective solvent production. Tuning the yeast extract (YE) concentration, using pure cysteine as the reducing agent and reducing trace metal concentration contribute to reasonable solvent production within a relatively short fermentation period. Tungsten is essential for cell growth and solvent production, while selenium is not required.

Supported Catalytically Active Liquid Metal Solutions: Liquid Metal Catalysis with Ternary Alloys, Enhancing Activity in Propane Dehydrogenation

Supported Catalytically Active Liquid Metal Solutions: Liquid Metal Catalysis with Ternary Alloys, Enhancing Activity in Propane Dehydrogenation

Determination of the maximum bioaccumulation capacity of various metals in leaves of two Tillandsia species.

Tillandsia species are plants from the Bromeliaceae family which display biomonitoring capacities in both active and passive modes. The bioaccumulation potential of Tillandsia aeranthos (Loisiel.) Desf. and Tillandsia bergeri Mez acclimated to Southern/Mediterranean Europe has never been studied. More generally, few studies have detailed the maximum accumulation potential of Tillandsia leaves through controlled experiments. The aim of this study is to evaluate the maximum accumulation values of seven metals (Co, Cu, Mn, Ni, Pb, Pt, and Zn) in T. aeranthos and T. bergeri leaves. Plants were immersed in different mono elemental metallic solutions of Co (II), Cu (II), Mn (II), Ni (II), Pb (II), Pt (IV), and Zn (II) ions at different concentrations. In addition, cocktail solutions of these seven metals at different concentrations were prepared to study the main differences and the potential selectivity between metals. After exposure, the content of these metals in the leaves were measured by inductively coupled plasma-optical emission spectrometry. Data sets were evaluated by a fitted regression hyperbola model and principal component analysis, maximum metal loading capacity, and thermodynamic affinity constant were determined. The results showed important differences between the two species, with T. bergeri demonstrating higher capacity and affinity for metals than T. aeranthos. Furthermore, between the seven metals, Pb and Ni showed higher enrichment factors (EF). T. bergeri might be a better bioaccumulator than T. aeranthos with marked selectivity for Pb and Ni, metals of concern in air quality biomonitoring.

Removal of cadmium ions from aqueous solution by raw, pretreated, and immobilized Pterocladia capillacea biomass

The adsorption of Cd (II) by Pterocladia capillacea in a batch system is the topic of the current investigation. Different pH (3–8) and starting Cd (II) concentrations were examined to determine the biosorption effectiveness for Cd (II) removal (20-100 ppm), period (5–120 min), agitation rate (50–250 rpm), and dose of biomass (0.01–0.1 g/50 ml of metal solution). At ideal conditions, the highest capability for bioadsorption was 8.407 mg g−1 dwt. The highest adsorption efficiency (96.047%) was attained by pretreating algal biomass using an autoclave. According to the findings, utilizing 0.1 g of alga produced the maximum removal efficiency compared to a control. Fourier transform infrared analysis of raw and processed algal biomass showed that hydroxyl, amide with hydrogen link, and carbonyl stretching before and during cadmium biosorption, carboxyl groups significantly contributed to biosorption. According to the findings, Pterocladia capillacea is an effective bioagent for removing cadmium from aqueous solutions.

The trapping effect of transitional metals on oxygen in Mo from first-principles calculations

The trapping effect of solute on oxygen (O) can be benefit for inhibiting its segregation and embrittlement at the GBs in Mo alloys. In this work, the interaction between solutes (including 27 transition metals), interstitial O and vacancy in Mo are implemented by first-principles calculations, and their trapping effects on O are evaluated by Simonovic’s model. Single transition metal solute (TMS) has a strong attraction for O, and it is strengthened by the second solute for all 3d, oversized 4d and 5d series. Furthermore, there is a significant synergistic effect between solute, vacancy, and oxygen for oversized solutes, i.e., the binding energy between solute atom (vacancy) and oxygen atoms is enhanced by the presence of vacancy (solute). The distribution of oxygen indicates that oxygen can be captured by dilute TMS atoms, and more oxygen atoms will be trapped as the solute concentration increases in Mo. Based on our extensive calculations, Sc, Ti, Zr, Hf, and Ta can be the top priority for suppressing the segregation and embrittlement of O in Mo alloys. It is interesting that the interaction between solute and O can be accurately separated into elastic and chemical contributions though delicate calculation, and the counterintuitive strong binding effect of fifth-nearest solute-O pairs for undersized 4d and 5d elements is owning to the chemical contribution driven by Coulomb interaction.

Analytical performance characteristics of Micro-structured surfaces for laser-induced breakdown spectroscopic analysis of liquids

We have previously shown the design and fabrication studies of 3-D micro-structured surfaces, to be used as a sample loading substrate for liquids analysis via dried-droplet LIBS methodology. Among the three designs, the substrate structured with 20-μm diameter cylinders, CYL-20, has shown the highest signal enhancement for the elements, Cu, Cr, and Pb, compared to 5-μm diameter cylinders, CYL-5, and 5-μm side-length triangular prisms, TAP-5, surfaces. Here, in this study, the analytical performance characteristics (LOD, accuracy, and precision) of these micro-structured Si-wafer surfaces are presented in comparison with unstructured surfaces. The dried-droplet residue of aqueous heavy metal solutions of Pb, Cr, and Cu were analyzed at their respective emission wavelengths under optimized experimental conditions. The results obtained from CYL-20 structured surfaces in comparison to 300 nm thin-film coated surfaces indicate up to 17, 11, and 7-fold increases in LIBS signal strength for Cu, Cr, and Pb, respectively. The experiments were performed using single and multi-element standards, and certified reference water samples. Sub-picogram absolute detection limits, 0.8 pg Pb, 0.5 pg Cu, and 0.45 pg Cr were obtained from the analysis of 500 nanoliters standard solutions, via dried-droplet methodology. Results with 70–75% accuracy and 95% precision were obtained from the repeated measurements. Though the results are promising, more extensive fabrication and application studies are required to find optimum structures of different sizes and shapes.

A molecular extraction process for vanadium based on tandem selective complexation and precipitation

Recycling vanadium from alternative sources is essential due to its expanding demand, depletion in natural sources, and environmental issues with terrestrial mining. Here, we present a complexation-precipitation method to selectively recover pentavalent vanadium ions, V(V), from complex metal ion mixtures, using an acid-stable metal binding agent, the cyclic imidedioxime, naphthalimidedioxime (H2CIDIII). H2CIDIII showed high extraction capacity and fast binding towards V(V) with crystal structures showing a 1:1 M:L dimer, [V2(O)3(C12H6N3O2)2]2−, 1, and 1:2 M:L non-oxido, [V(C12H6N3O2)2] ̶ complex, 2. Complexation selectivity studies showed only 1 and 2 were anionic, allowing facile separation of the V(V) complexes by pH-controlled precipitation, removing the need for solid support. The tandem complexation-precipitation technique achieved high recovery selectivity for V(V) with a selectivity coefficient above 3 × 105 from synthetic mixed metal solutions and real oil sand tailings. Zebrafish toxicity assay confirmed the non-toxicity of 1 and 2, highlighting H2CIDIII’s potential for practical and large-scale V(V) recovery.

A feasible approach to measure metal concentrations in drill hole waters on site for mineral exploration

The new technologies used in the green transition towards carbon-free societies typically demand extensive use of metals. This leads to a heavily growing need for exploration and extraction of ore deposits. Exploration can be facilitated by measuring metal concentrations in ground and surface waters carrying trace concentrations of metals leached from nearby deposits. Currently, measuring metal concentrations in water is slow and expensive and it cannot be done on-site, which hinders the discovery of new ore deposits. To address this challenge, we have developed a method to collect and concentrate the dissolved metals in a solid filter and measure the metal concentrations directly from the filter with a portable X-ray fluorescence spectrometer. The permeable filter is made of mesoporous silicon modified with bisphosphonates. Two types of adsorbing materials for the filters were prepared based on scalable production methods: i) regenerative etching of metallurgical grade silicon powder, and ii) magnesiothermic reduction of silica from barley husks. Empirical calibrations were prepared in a concentration range of 10–200 μg/L for Mn, Co, Ni, Cu, Zn, and Pb using water samples prepared by spiking well water with standard metal solutions. Both filter types were tested for their ability to adsorb metals from the real water samples taken from drill holes. The developed system was able to detect metal concentrations down to 12 μg/L (ppb) showing its potential for on-site measurements of dissolved metals in water samples, which could be feasible in the discovery of new mineral deposits. This innovation enables smart sampling during exploration and provides real-time information on metal concentrations in water.