<p><strong>Gold–silver synergism in luminescent nanoclusters has been widely studied, typically by altering Au:Ag ratios. Here, we systematically investigated the effect of maturing conditions while keeping the ratio constant (5:1). Reference systems of gold nanoclusters and proteins were also examined.</strong></p><p>Maturing conditions significantly influenced fluorescence and synergism, with the strongest effect observed at 37 °C for 2.5 h. Luminescence stability was further tested in the presence of Cu(II) and Fe(III) ions, which caused varying extents of quenching. These findings reveal maturing as a key factor controlling Au–Ag synergism and nanocluster luminescence.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385"><strong>Maturing conditions of bimetallic nanocomposites as a new factor influencing Au–Ag synergism and impact of Cu(II) and/or Fe(III) on luminescence</strong></a></h4><p>Veronika Svačinová, Tomáš Pluháček, Martin Petr and Karolina Siskova</p><p><span>R. Soc. Open Sci.12: 241385</span></p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1098/rsos.241385">https://doi.org/10.1098/rsos.241385</a></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><p><strong>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.</strong></p><p>In the present work, we show that besides varying the Au : Ag ratio in the reaction mixture (as known from the literature), there is another possibility for tuning Au–Ag synergism while keeping the same molar ratio of Au : Ag in the reaction mixture. We introduce a new parameter and call it <i>maturing conditions</i>. The maturing conditions of GSNCs involved either time variations (0 h, 1.25 h, 2.5 h) at room temperature or elevated temperatures (37°C, 50°C) kept for 2.5 h. Indeed, we discovered that the <i>time of sample maturing</i> at room temperature (i.e. the delay between the sample synthesis and its purification by dialysis), possessing otherwise the same composition (i.e. reactant concentrations, their same molar ratios), being mixed exactly in the same way and under the same conditions, has a tremendous impact on their final luminescent features. When we compared our GSNCs to the identically synthesized and matured AuNCs entrapped in BSA and determined their FQY (which is more accurate than the direct comparison of fluorescence emission intensity, especially when the fluorescence maximum shifts and the width of fluorescence band changes), it turned out that the Au–Ag synergism can be achieved in specific cases exclusively.</p><p>Furthermore, inspired by the biological origin and function of the used protein, we have also investigated the influence of <i>physiological</i> (37°C) versus <i>elevated temperature</i> (50°C) in the direct comparison to room temperature maturing in the process of prolonged sample <i>maturing</i> (2.5 h). While GSNCs matured at 37°C for 2.5 h provided the best Au–Ag synergism, elevated temperature during sample maturing (50°C) led rather to changes of the protein secondary structure (determined by circular dichroism) and virtually no Au–Ag synergistic effect was observed. The results reveal that Au–Ag synergism can be finely tuned by setting appropriate maturing conditions of bimetallic nanoclusters embedded in the protein scaffold. Maturing conditions thus represent a new factor in the viewpoint of Au–Ag synergism.</p><p>For the most prominent GSNCs, revealing the best synergism, it is demonstrated that the fluorescence of GSNCs can be quenched more efficiently by an excess of Cu(II) rather than Fe(III) ions. The exact mechanism is currently unknown, but a plausible reason is suggested by us and further investigations are envisaged. Since both selected metal ions are crucial in various cellular metabolic pathways and their impaired metabolism related to several neurodegenerative diseases and/or cancer [<a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#B27">27</a>], their impact on GSNC represents an important issue.</p><h4><strong>2. Results and discussion</strong></h4><h5><strong>2.2. Characterization of the samples and evaluation of Au–Ag synergism</strong></h5><h5><strong>2.2.1. Metallic part characterization (by ICP-MS, XPS, UV–visible absorption)</strong></h5><p>Theoretical and experimental concentrations (in mg ml<sup>−1</sup>) of Au and Ag in each metallic sample (GSNC and AuNC types) are summarized in electronic supplementary material, table SI-1; while the molar ratio of Au : Ag (theoretical and experimental) for bimetallic GSNC samples is calculated in electronic supplementary material, table SI-2. It should be noted that the experimental values of Au and Ag concentrations were accurately determined by ICP-MS. Interestingly, the experimental values of Au contents slightly increased from 368 ± 4 to 381 ± 6 µg ml<sup>−1</sup> with prolonged time of maturing applied at room temperature (electronic supplementary material, table SI-1). It thus corroborated the assumption that prolonged time may have an effect on metallic ion incorporation into the protein scaffold. Obviously, it is valid only for Au(III), while not for Ag(I) because the experimental content of Ag is around 40 ± 3 µg ml<sup>−1</sup> in all types of GSNC samples (electronic supplementary material, table SI-1). Differences in Ag incorporation between individual GSNC samples are only negligible; they lie within the experimental error. The GSNC samples matured at elevated temperature (50°C) for prolonged time (2.5 h) did not cause any significant increase of Au content in comparison to the samples matured at room temperature for the same period (electronic supplementary material, table SI-1). On the other hand, usage of the physiological temperature of maturing led to Au(III) content slight decreasing (but within 8%). Based on the experimental concentration values of both metals, Au and Ag, the percentage yield of each metal within a particular metallic (GSNCs as well as AuNCs) sample can be calculated, the values being listed in <a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#T1">table 1</a>.</p><p>To determine oxidation states of Au and Ag within our metallic samples, XPS measurement has been employed. The XPS signals of GSNC samples are shown in <a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#F2">figure 2</a>, while those of AuNC samples in electronic supplementary material, figure SI-1.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/R_Soc_Open_Sci_12_241385_Figure_2_XPS_signals_in_Au_and_Ag_characteristic_regions_recorded_for_our_representative_metallic_samples_48f172bbe5.jpg" alt="R. Soc. Open Sci. 12: 241385: Figure 2. XPS signals in Au and Ag characteristic regions recorded for our representative metallic samples: (A) Au 4f region of GSNC 0 h RT, (B) Ag 3d region of GSNC 0 h RT, (C) Au 4f region of GSNC 1.25 h RT, (D) Ag 3d region of GSNC 1.25 h RT, (E) Au 4f region of GSNC 2.5 h RT, (F) Au 4f region of GSNC 2.5 h 37°C, (G) Ag 3d region of GSNC 37°C, and (H) Au 4f region of GSNC 2.5 h 50°C." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_R_Soc_Open_Sci_12_241385_Figure_2_XPS_signals_in_Au_and_Ag_characteristic_regions_recorded_for_our_representative_metallic_samples_48f172bbe5.jpg 86w," sizes="100vw" width="825" height="1500"></p><h5><strong>2.2.3. Luminescent properties of gold–silver nanoclusters and extent of Au–Ag synergism</strong></h5><p>Fluorescence emission was measured using the same excitation wavelength (460 nm) to investigate luminescent properties of GSNC samples generated under different maturing conditions. Normalized spectra are depicted in <a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#F4">figure 4</a>.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/R_Soc_Open_Sci_12_241385_Figure_4_Fluorescence_emission_of_GSNC_samples_matured_under_different_conditions_d39d57b30c.jpg" alt="R. Soc. Open Sci. 12: 241385: Figure 4. Fluorescence emission of GSNC samples matured under different conditions: 0 h RT (green curve), 1.25 h RT (black curve), 2.5 h RT (brown curve), 2.5 h 37°C (blue curve) and 2.5 h 50°C (red curve). Excitation was at 460 nm in all five cases. Normalized spectra are shown for the sake of a clear presentation of intensity maximum shifts and emission band broadening." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_R_Soc_Open_Sci_12_241385_Figure_4_Fluorescence_emission_of_GSNC_samples_matured_under_different_conditions_d39d57b30c.jpg 189w," sizes="100vw" width="1000" height="827"></p><p>The position of emission maximum of GSNC 0 h RT sample is located at 615 nm (<a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#F4">figure 4</a>). This corresponds very well to the position of fluorescence emission maxima reported for Au : Ag systems (also 5 : 1 ratio) prepared by Zhang <i>et al</i>., albeit they exploited peptide (GSH) as the template for nanocluster synthesis [<a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#B6">6</a>]. While prolonging the maturing time, the emission maximum red-shifts to 625 nm and further to 640 nm (<a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#F4">figure 4</a>) as obvious for GSNC 1.25 h RT and GSNC 2.5 h RT, respectively. While increasing the maturing temperature, the emission maximum continues to red-shift to 685 nm (GSNC 2.5 h 50°C). Similarly, the emission maxima of our monometallic AuNC samples red-shifted gradually either by 5 nm (going from samples matured at room temperature for 0 h (655 nm) to that matured for 2.5 h at 37°C (670 nm)), or by 10 nm (for the AuNCs matured at 50°C for 2.5 h) as can be clearly seen in electronic supplementary material, figure SI-4.</p><h4><strong>3. Conclusions</strong></h4><p>In this work, maturing conditions representing a new factor that can help to adjust Au–Ag synergism are introduced and investigated. Maturing is defined here as the procedure between the synthesis (finished by MW irradiation) and the dialysis (that stops the nanostructure evolution). It is well documented that this factor has been overlooked, underestimated, not considered or investigated intentionally so far. Au–Ag synergism is evaluated as the ratio of FQY values of GSNCs versus AuNCs. Bimetallic (GSNCs) and monometallic (AuNCs) nanocomposites were synthesized using MW irradiation and exploiting protein as a template to restrict the growth, so that luminescent nanoclusters and not plasmonic particles are formed. The protein treated in the same way (during the synthesis and maturing procedure) as the metallic nanocomposites served as a referent system. The selected variations of maturing conditions included either time (0 h, 1.25 h, 2.5 h) or temperature (room temperature, 37°C, 50°C). It was revealed that maturing time plays a significant role leading to an increase of Au–Ag synergistic effect. Based on the increasing Au–Ag synergism, the GSNC samples can be arranged as follows: 0 h RT &lt; 1.25 h RT &lt; 2.5 h 50°C &lt; 2.5 h RT &lt; 2.5 h 37°C. Regarding nanocluster size increase and PSD broadening, both evidenced by STEM (for metallic parts only) and DLS (hydrodynamic diameter of the whole nanocomposite in aqueous solution), the nanocomposites can be arranged into the order: 0 h RT &lt; 2.5 h RT &lt; 2.5 h 50°C. This order does not correlate with the observed increase of Au–Ag synergistic effect. In fact, a temperature of 50°C held for 2.5 h influences the secondary structure of the protein matrix significantly. Therefore, besides the increasing nanocluster size and PSD broadening during GSNC maturing, other factors, such as changes of the protein secondary structure for instance, play a key role in Au–Ag synergism as well. The results thus imply that maturing conditions of GSNC samples represent a very important factor leading to a further fine tuning of their luminescent properties, hypothetically by the different structural arrangement of atoms within Au–Ag nanoclusters. The stability of the GSNC luminescent signal was further investigated in the presence of Cu(II) and/or Fe(III) because these two selected metal cations are relevant cofactors in living systems. The observed differences in the extent of luminescence quenching caused by Cu(II) and/or Fe(III) in the concentration range of 0−20 mM were discussed and a plausible reason for such a phenomenon was suggested.</p><h4><strong>4. Methods</strong></h4><h5><strong>4.4. Inductively coupled plasma mass spectrometry</strong></h5><p>Before ICP-MS analysis, 500 µl GSNC aliquots were dried in a vacuum rotary evaporator to dryness. The total silver and gold levels were accurately determined using a validated ICP-MS method [<a target="_blank" rel="noopener noreferrer" href="https://royalsocietypublishing.org/doi/10.1098/rsos.241385#B47">47</a>]. Briefly, the dried aliquots were digested using a digestion mixture of 2 ml of concentrated nitric acid and 2 ml of concentrated hydrochloric acid in an MLS 1200 mega closed vessel microwave digestion unit (Milestone, Italy) according to the power-controlled digestion programme. The digests were allowed to cool down to laboratory temperature and diluted with ultrapure water in 25 ml volumetric flasks. The total silver and gold levels were acquired by an Agilent <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=10&amp;search=7700x+ICP-MS"><strong>7700x ICP-MS</strong></a> (Agilent Technologies Ltd, Japan) using seven-point external calibration within a concentration of 10–2000 µg l<sup>−1</sup> for Ag and 100–10 000 µg l<sup>−1</sup> for Au. The quality control sample at a concentration level of 500 µg l<sup>−1</sup> for Ag and 5000 µg l<sup>−1</sup> for Au was regularly analysed every ten samples to ensure the quality of the acquired results. All ICP-MS measurements were performed in six replicates, and the results are expressed as an average ± s.d.</p><h5><strong>4.7. X-ray photoelectron spectroscopy</strong></h5><p>The XPS measurements of most samples were carried out with a PHI 5000 VersaProbe II XPS system (Physical Electronics) with a monochromatic Al-K<sub>α</sub> source (15 kV, 50 W) and a photon energy of 1486.7 eV. All the spectra were measured in a vacuum of 1.1 × 10<sup>–7</sup> Pa and at a room temperature of 20°C. Dual beam charge compensation was used for all measurements. The spectra were evaluated with MultiPak software, version 9 (Ulvac-PHI, Inc., Chanhassen, MN, USA).</p><p>The sample labelled as GSNC 0 min RT was analysed with a <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/products/2166"><strong>Nexsa G2 XPS system </strong></a>(Thermo Fisher Scientific) also equipped with a monochromatic Al-K<sub>α</sub> source and photon energy of 1486.7 eV. The spectral acquisition was maintained at 1.6 × 10<sup>–9</sup> mBar, and at a controlled ambient temperature of 20°C. Charge neutralization techniques were systematically employed throughout the measurement. Spectral analysis and data interpretation were conducted using Avantage software version 6.5.1 provided by Thermo Fisher Scientific.</p>

Maturing conditions of bimetallic nanocomposites as a new factor influencing Au–Ag synergism and impact of Cu(II) and/or Fe(III) on luminescence

Single-atom-enhanced membrane for simultaneous bacteria and heavy metal on-site water treatment

<p><strong>This study investigates nutrient exchange between lunar and martian regolith simulants and bioregenerative life support system (BLiSS) effluent. Using ICP-OES, sorption and dissolution processes were quantified, revealing significant release of elements such as S, Ca, Mg, and Na from the simulants.</strong></p><p>Surface and structural analyses confirmed elemental bonding and mineral alterations after reaction. The findings demonstrate that regolith can supply essential nutrients to BLiSS systems, supporting sustainable agriculture in extraterrestrial environments and highlighting the importance of realistic effluent simulations.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsearthspacechem.5c00267"><strong>Lunar and Martian Regolith Simulants Desorb and Weather after Exposure to Bioregenerative Life Support System Effluent</strong></a></h4><p>Harrison R. Coker, Daniella Saetta, Misle M. Tessema, Jackson L. Smith, Charles A. Richardson-Gongora, Jason A. Fischer, Hannah I. Roberts, Luke B. Roberson, and Julie A. Howe*</p><p>ACS Earth Space Chem. 2026, 10, 2, 441–454</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acsearthspacechem.5c00267">https://doi.org/10.1021/acsearthspacechem.5c00267</a></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><p><strong>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.</strong></p><div><div><h5><strong>Background</strong></h5><p>Inorganic nutrient solutions (e.g., Hoagland’s <a href="javascript:void(0);">(1)</a>) are useful for growing plants in soilless systems but require continuous nutrient inputs that are consumed as plants grow. With future plans for lunar and Mars settlements, dependency on Earth-sourced fertilizers will hinder efficient operations. Therefore, extracting nutrients from regolith to enhance sustainable agricultural operations, or improving the regolith’s fertility such that plants directly derive nutrients from the regolith, are both effective strategies that support diverse cropping operations to produce food and fiber resources through in situ resource utilization (ISRU). <a href="javascript:void(0);">(2,3)</a> Broadly, approaches that utilize surface resources from the Moon and Mars to reduce inputs from Earth are deemed ISRU. <a href="javascript:void(0);">(4)</a></p></div><div><h5><strong>In Situ Resource Utilization</strong></h5><p>The extraction of raw elements from regolith is a primary goal of ISRU. <a href="javascript:void(0);">(4)</a> Various approaches for enhanced dissolution of regolith have been studied, <a href="javascript:void(0);">(5)</a> including techniques such as ionic liquids, <a href="javascript:void(0);">(6)</a> eutectic salts, <a href="javascript:void(0);">(7)</a> electro-deoxidation, <a href="javascript:void(0);">(8)</a> and heat treatment. <a href="javascript:void(0);">(9)</a> While promising, these approaches have the downfall of requiring exogenous chemicals, energy, and technology. Alternatively, a basic approach will encompass using resources such as BLiSS effluent to physically weather the regolith. Because of the underlying basaltic mineralogy of lunar and martian regoliths, hydrologic weathering may be a rapid process that deserves further investigation.<named-content></named-content></p></div><div><h5><strong>Bioregenerative Life Support Systems</strong></h5><p>To recycle consumed nutrients from undesirable plant and human wastes, the use of bioregenerative life support systems (BLiSS) that decompose organic matter into inorganic nutrient streams will be used. <a href="javascript:void(0);">(10)</a> Organic wastes (e.g., plant material, human wastes, etc.) generated by lunar and martian astronauts will necessitate recycling via a series of BLiSS bioreactors that result in effluent streams of water, inorganic nutrients, and metabolites of anerobic digestion, which include various volatile organic acids. <a href="javascript:void(0);">(11)</a> A working BLiSS prototype at Kennedy Space Center (KSC), called the organic processing assembly (OPA), utilizes dual-stage anerobic bioreactors and membrane filtration <a href="javascript:void(0);">(12,13)</a> to accomplish decomposition of organic matter, which is subsequently fed to a phototrophic membrane bioreactor <a href="javascript:void(0);">(14)</a> for the complete oxidation of N species. The microbiome of OPA varies across reactors as a function of varying inputs and substrate decomposition. <a href="javascript:void(0);">(15)</a> While OPA is a developing technology in both biological processing and technological command, analogous BLiSS, will be required to create a circular economy of nutrients in space. <a href="javascript:void(0);">(16)</a> Because BLiSS produces nutrient streams that differ from those of inorganic nutrient solutions, investigating fundamental interactions of BLiSS effluent with regolith simulants will help guide future planning and determine uses of effluent for outposts on the Moon and Mars. In this study, effluent from the OPA at KSC was utilized, as it is a high-fidelity prototype of what may be produced in spaceflight and on lunar and martian outposts.</p></div><div><h5><strong>Lunar and Martian Regolith</strong></h5><p>Lunar regolith is relatively homogeneous in elemental composition, with the major difference being the abundance of Ca. A useful classification refers to lunar samples as being “high-Ca” or “low-Ca” above or below 13.5 wt % CaO. <a href="javascript:void(0);">(17)</a> Increasing abundance of nanophase Fe, along with decreasing grain size, is characteristic of more mature lunar regolith. <a href="javascript:void(0);">(18)</a> Lunar samples exhibit low electrical conductivity (EC), though the electrical properties of lunar regolith are especially sensitive to thermal and atmospheric changes. <a href="javascript:void(0);">(19,20)</a> In general, the chemical reactivity of lunar regolith to organic molecules is not well understood, <a href="javascript:void(0);">(21)</a> but as aqueous and oxidizing environments are introduced to support plant life, it should be expected that lunar regolith will drastically change. For instance, exposure to water vapor increases the adsorption of N<sub>2</sub> and Ar, <a href="javascript:void(0);">(22)</a> while the crushing of regolith promotes the movement of trapped vaporous gases into solution. <a href="javascript:void(0);">(23)</a> Lunar simulants have additionally demonstrated increased generation of reactive oxygen species (ROS) (e.g., H<sub>2</sub>O<sub>2</sub> and OH<sup>–</sup>) in micromolar quantities when crushed and exposed to the atmosphere. <a href="javascript:void(0);">(24)</a> Lunar regolith contains up to 70% agglutinates by volume, <a href="javascript:void(0);">(25)</a> which are aggregates of mineral/lithic fragments fused together by rapid melting and cooling of glass after meteoroid impacts. Agglutinates are noted to have differing abundances of nanophase Fe<sup>0</sup>, with several hypotheses accounting for their incorporation into the lunar regolith. <a href="javascript:void(0);">(26)</a></p><p>Martian astronauts will have greater accessibility to specific and diverse minerals for ISRU than lunar astronauts. For Mars, there is likely a semiactive hydrologic cycle of hydrated brines <a href="javascript:void(0);">(27−30)</a> that may even support microbial life. <a href="javascript:void(0);">(31)</a> Although glass is a more common feature of lunar regolith, in analog martian sites on Earth, glass-matrices have been identified as the possible profile-controlling minerals. <a href="javascript:void(0);">(32)</a> Martian regolith is high in Fe metal oxides, <a href="javascript:void(0);">(33)</a> chloride, <a href="javascript:void(0);">(34)</a> and sulfate salts, <a href="javascript:void(0);">(35)</a> including perchlorates (ClO<sub>4</sub><sup>–</sup>) and other oxidants, such as hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), which occur at toxic levels for plants. These salts may limit bioavailability of various metals. <a href="javascript:void(0);">(36)</a> Oxidized nitrogen species, simple organics, oxychlorine phases, and sulfates are widespread, with phyllosilicates and carbonates occurring in select Gale Crater materials, and it appears that geochemical conditions and organic C may have once been favorable for microbial life. <a href="javascript:void(0);">(37,38)</a> Recent evidence from the Phoenix landing site quantified organic C at 83–1484 μg C g<sup>–1</sup> and carbonates from 1.1 to 2.6 wt %. <a href="javascript:void(0);">(39)</a> At Gale Crater, the 2007 Phoenix Mars Scout Mission’s Wet Chemistry Laboratory (WCL) conducted in situ experiments at the Phoenix landing site and found solutions were dominated by ClO<sub>4</sub><sup>–</sup>, Mg<sup>2+</sup>, and Na<sup>+</sup>, at mM levels, with sub-mM concentrations of Ca<sup>2+</sup>, K<sup>+</sup>, and Cl<sup>–</sup> and a pH of 7.7.<sup>34</sup> The minimal leachable ions from surface samples had a corrected electrical conductivity (EC) ranging from 1370 to 1900 μS cm<sup>–1</sup> at 25 °C. As the WCL extraction cell measured soil extracts at 1:25 (solid/solution), the reported EC values would likely be 5–25 times higher using traditional soil approaches (saturated paste extract; 1:1–1:5), indicating a highly saline soil that will need to be remediated prior to being used as a plant growth substrate, of which leaching with BLiSS solutions may be an effective management strategy.</p><h4><strong>Methods</strong></h4><h5><strong>Analyses</strong></h5><p>After the 24 h batch experiment, the pH and electrical conductivity (EC) of the reacting solutions were measured to assess changes to solution chemistry after weathering. Solutions were acidified to 1% HNO<sub>3</sub> and analyzed via inductively coupled plasma-optical emission spectroscopy <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=3&amp;search=iCAP+7000"><strong>(ICP-OES) (Thermo Scientific, iCAP 7000)</strong></a> in duplicate. Ion chromatography was used to analyze the ions without any sample preparation. Substrate samples were Au sputter-coated (Denton Vacuum, Desk IV) and mounted prior to scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) (Jeol, JSM-IT800). <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/products/2166"><strong>X-ray photoelectron spectroscopy (XPS) (Thermo Scientific, Nexsa G2)</strong></a> was used on substrates to identify elemental bonding associations by using <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/products/1489"><strong>Qtegra software</strong></a>. XPS data were processed in the Avantage Data System. X-ray diffraction (XRD) (Malvern Panalytical, Empyrean) was used to assess mineralogical changes to substrates and was performed using Bragg–Brentano mode. The diffraction data were recorded from 15 to 70 two-theta (2θ) degrees. HighScore curve fitting software was used to process the diffraction pattern and compared to the PDF-4+2023 International Center of Diffraction Database (ICDD).</p><h4><strong>Results</strong></h4><h5><strong>Weathering of Substrates</strong></h5><p>Visual observations of the substrates after the batch experiment revealed weathering to the minerals. In JSC-1A, the sharp mineral edges appeared to have some rounded-off features that reduced the overall sharpness of corners and edges (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsearthspacechem.5c00267#fig5">Figure 5</a>); however, a quantitative analysis was not available to indicate if mineral sharpness was statistically reduced. In general, the overall particle size was not substantially reduced in a survey of all of the minerals. Notable artifacts of the weathering process include holes in the mineral faces where small particles collapsed and the appearance of webbing patterns in the anorthosite fraction of JSC-1A. Unfortunately, EDS was not able to detect any sorbed elements in these features (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsearthspacechem.5c00267#fig6">Figure 6</a>). Because the detection limits of EDS are ∼1000 mg kg<sup>–1</sup>, it is reasonable that no sorbed features were detected, given that measured sorption densities after batch experimentation were lower than EDS detection limits. Further, the probed volume at a given electron energy is below the surface, whereas adsorbents are likely only located on the mineral surface.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Earth_Space_Chem_2026_10_2_441_454_Figure_5_Lunar_simulant_JSC_1_A_imaged_with_scanning_electron_microscope_SEM_9c6a2aac87.jpg" alt="ACS Earth Space Chem. 2026, 10, 2, 441–454: Figure 5. Lunar simulant JSC-1A imaged with scanning electron microscope (SEM). The electron beam energy ranged from 1 to 3 kV. The Hoagland’s and effluent images are after the 24 h batch experiment." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Earth_Space_Chem_2026_10_2_441_454_Figure_5_Lunar_simulant_JSC_1_A_imaged_with_scanning_electron_microscope_SEM_9c6a2aac87.jpg 245w," sizes="100vw" width="2000" height="1077"></p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Earth_Space_Chem_2026_10_2_441_454_Figure_6_Scanning_electron_microscope_SEM_image_of_erosion_spots_on_lunar_simulant_JSC_1_A_after_batch_experiment_7c38902bc6.jpg" alt="ACS Earth Space Chem. 2026, 10, 2, 441–454: Figure 6. Scanning electron microscope (SEM) image of erosion spots on lunar simulant JSC-1A after batch experiment. Electron dispersive spectroscopy (EDS) was used to investigate the elemental abundance of erosion regions and was set to 30 keV." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Earth_Space_Chem_2026_10_2_441_454_Figure_6_Scanning_electron_microscope_SEM_image_of_erosion_spots_on_lunar_simulant_JSC_1_A_after_batch_experiment_7c38902bc6.jpg 245w," sizes="100vw" width="2083" height="1199"></p><h5><strong>Chemical Interaction</strong></h5><p>The elements C, N, P, and Ca were investigated with high-resolution XPS. For C, a major peak at ∼286 eV was observed in all substrates and solutions that corresponded to C–O bonding. Hoagland’s and effluent did not affect the XPS spectra significantly in JSC-1A; however, in MGS-1, there was a notable increase in the Hoagland’s and effluent-treated regolith at ∼294 eV, which corresponds to CF<sub>3</sub> (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsearthspacechem.5c00267#fig9">Figure 9</a>). Because F was not quantified, it is difficult to know if F was in differing concentrations between solutions. Hoagland’s was made from DI water and effluent processes a mixture of fecal simulant and tap water; it is unlikely that F was greater in Hoagland’s.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Earth_Space_Chem_2026_10_2_441_454_Figure_9_Carbon_C_1s_peaks_of_lunar_JSC_1_A_and_martian_MGS_1_simulants_as_unaltered_materials_and_after_batch_experiment_using_XPS_82622dd14c.jpg" alt="ACS Earth Space Chem. 2026, 10, 2, 441–454: Figure 9. Carbon (C 1s) peaks of lunar (JSC-1A) and martian (MGS-1) simulants as unaltered materials and after batch experiment using XPS." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Earth_Space_Chem_2026_10_2_441_454_Figure_9_Carbon_C_1s_peaks_of_lunar_JSC_1_A_and_martian_MGS_1_simulants_as_unaltered_materials_and_after_batch_experiment_using_XPS_82622dd14c.jpg 245w," sizes="100vw" width="2079" height="980"></p><h4><strong>Conclusion</strong></h4><p>The hydrologic weathering of lunar and martian regolith simulants by BLiSS streams demonstrated increased plant essential nutrients and metals in solution due to highly soluble compounds and easily weatherable mineralogy. Multielement competitive sorption demonstrates low removal of P and K, but high supplementation of Ca, Mg, and S to the solution. The mechanistic differences between the organic BLiSS effluent and the inorganic nutrition solution were predominantly unaccounted for. It stands to reason that longer-term studies may follow up with the provided results to fully determine how supplementation of BLiSS solutions can be obtained from weathering of the regolith. Therefore, further experimentation that improves upon the extraction of elements of interest and increases the reaction time will be useful in fortifying the sustainability of human operations. The hydrologic weathering of sharp mineral edges also deserves quantitative investigation over time to understand whether reducing the abrasiveness of regolith offers an additional aspect of using BLiSS effluent on lunar and martian surface minerals.</p></div></div>

Lunar and Martian Regolith Simulants Desorb and Weather after Exposure to Bioregenerative Life Support System Effluent

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