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1. Dissolution kinetics of a sodium borosilicate glass in Tris buffer solutions: impact of Tris concentration and acid (HCl/HNO ₃ ) identity

   https://doi.org/10.1039/D0CP06425D  

   Stone-Weiss, Nicholas; Smith, Nicholas J.; Youngman, Randall E.; Pierce, Eric M.; Goel, Ashutosh (August 2021, Physical Chemistry Chemical Physics)

   Understanding the corrosion behavior of glasses in near-neutral environments is crucial for many technologies including glasses for regenerative medicine and nuclear waste immobilization. To maintain consistent pH values throughout experiments in the pH = 7 to 9 regime, buffer solutions containing tris(hydroxymethyl)aminomethane (“Tris”, or sometimes called THAM) are recommended in ISO standards 10993-14 and 23317 for evaluating biomaterial degradation and utilized throughout glass dissolution behavior literature—a key advantage being the absence of dissolved alkali/alkaline earth cations ( i.e. Na + or Ca 2+ ) that can convolute experimental results due to solution feedback effects. Although Tris is effective at maintaining the solution pH, it has presented concerns due to the adverse artificial effects it produces while studying glass corrosion, especially in borosilicate glasses. Therefore, many open questions still remain on the topic of borosilicate glass interaction with Tris-based solutions. We have approached this topic by studying the dissolution behavior of a sodium borosilicate glass in a wide range of Tris-based solutions at 65 °C with varied acid identity (Tris–HCl vs. Tris–HNO 3 ), buffer concentration (0.01 M to 0.5 M), and pH (7–9). The results have been discussed in reference to previous studies on this topic and the following conclusions have been made: (i) acid identity in Tris-based solutions does not exhibit a significant impact on the dissolution behavior of borosilicate glasses, (ii) ∼0.1 M Tris-based solutions are ideal for maintaining solution pH in the absence of obvious undesirable solution chemistry effects, and (iii) Tris–boron complexes can form in solution as a result of glass dissolution processes. The complex formation, however, exhibits a distinct temperature-dependence, and requires further study to uncover the precise mechanisms by which Tris-based solutions impact borosilicate glass dissolution behavior. 

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2. Lateral, Vertical, and Temporal Variability of Seawater Carbonate Chemistry at Hog Reef, Bermuda

   https://doi.org/10.3389/fmars.2021.562267  

   Pezner, Ariel K.; Courtney, Travis A.; Page, Heather N.; Giddings, Sarah N.; Beatty, Cory M.; DeGrandpre, Michael D.; Andersson, Andreas J. (February 2021, Frontiers in Marine Science)

   null (Ed.)

   Spatial and temporal carbonate chemistry variability on coral reefs is influenced by a combination of seawater hydrodynamics, geomorphology, and biogeochemical processes, though their relative influence varies by site. It is often assumed that the water column above most reefs is well-mixed with small to no gradients outside of the benthic boundary layer. However, few studies to date have explored the processes and properties controlling these multi-dimensional gradients. Here, we investigated the lateral, vertical, and temporal variability of seawater carbonate chemistry on a Bermudan rim reef using a combination of spatial seawater chemistry surveys and autonomous in situ sensors. Instruments were deployed at Hog Reef measuring current flow, seawater temperature, salinity, pH T , p CO 2 , dissolved oxygen (DO), and total alkalinity (TA) on the benthos, and temperature, salinity, DO, and p CO 2 at the surface. Water samples from spatial surveys were collected from surface and bottom depths at 13 stations covering ∼3 km 2 across 4 days. High frequency temporal variability in carbonate chemistry was driven by a combination of diel light and mixed semi-diurnal tidal cycles on the reef. Daytime gradients in DO between the surface and the benthos suggested significant water column production contributing to distinct diel trends in pH T , p CO 2 , and DO, but not TA. We hypothesize these differences reflect the differential effect of biogeochemical processes important in both the water column and benthos (organic carbon production/respiration) vs. processes mainly occurring on the benthos (calcium carbonate production/dissolution). Locally at Hog Reef, the relative magnitude of the diel variability of organic carbon production/respiration was 1.4–4.6 times larger than that of calcium carbonate production/dissolution, though estimates of net organic carbon production and calcification based on inshore-offshore chemical gradients revealed net heterotrophy (−118 ± 51 mmol m –2 day –1 ) and net calcification (150 ± 37 mmol CaCO 3 m –2 day –1 ). These results reflect the important roles of time and space in assessing reef biogeochemical processes. The spatial variability in carbonate chemistry parameters was larger laterally than vertically and was generally observed in conjunction with depth gradients, but varied between sampling events, depending on time of day and modifications due to current flow. 

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3. Towards Immobilized Proton-Coupled Electron Transfer Agents for Electrochemical Carbon Capture from Air and Seawater

   https://doi.org/10.1149/1945-7111/ad4a0f  

   Ali, Fawaz; Bilger, David; Patamia, Evan_D; Andrew, Trisha_L; Kwabi, David_G (May 2024, Journal of The Electrochemical Society)

   Electrochemical CO₂separation has drawn attention as a promising strategy for using renewable energy to mitigate climate change. Redox-active compounds that undergo proton-coupled electron transfer (PCET) are an impetus for pH-swing-driven CO₂capture at low energetic costs. However, multiple barriers hinder this technology from maturing, including sensitivity to oxygen and the slow kinetics of CO₂capture. Here, we use vapor phase chemistry to construct a textile electrode comprising an immobilized PCET agent, poly(1-aminoanthraquinone) (PAAQ), and incorporate it into redox flow cells. This design contrasts with others that use dissolved PCET agents by confining proton-storage to the surface of an electrode kept separate from an aqueous, CO₂-capturing phase. This system facilitates carbon capture from gaseous sources (a 1% CO₂feed and air), as well as seawater, with the latter at an energetic cost of 202 kJ/mol_CO2, and we find that quinone moieties embedded within the electrode are more stable to oxygen than dissolved counterparts. Simulations using a 1D reaction-transport model show that moderate energetic costs should be possible for air capture of CO₂with higher loadings of polymer-bound PCET moieties. The remarkable stability of this system sets the stage for producing textile-based electrodes that facilitate pH-swing-driven carbon capture in practical situations. 

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4. Beaufort Gyre Observing System (BGOS) Underway Partial pressure of carbon dioxide (pCO2) data and air-sea CO2 fluxes, Arctic Ocean, 2011-2021

   https://doi.org/10.18739/A26H4CR80  

   DeGrandpre, Michael (January 2022, NSF Arctic Data Center)

   These data were collected on the CCGS (Canadian Coast Guard) Louis St. Laurent during BGOS (Beaufort Gyre Observing System) research cruises in 2012-2014 and 2016-2021 in the Beaufort Sea area. They are underway pCO2 (Partial pressure of carbon dioxide) data collected using an equilibrator-infrared method (SUPER CO2 system from Sunburst Sensors). Ancillary data for calculation of air-sea CO fluxes include temperature, salinity, atmospheric CO2, wind speed, and gas transfer velocity (calculated from Wanninkhof et al. (2009). Fluxes are not corrected for fractional ice-coverage. The specific goal of the study is to continue to operate an Arctic Observing Network (AON) for the measurement of the partial pressure of CO2 (pCO2), pH, and dissolved O2 (DO) focused on the surface waters of the Arctic Ocean (specifically, the Canada Basin). These data were collected on the CCGS (Canadian Coast Guard) Louis St. Laurent during a BGOS (Beaufort Gyre Observing System) research cruise in the Beaufort Sea area. It is underway pCO2 (partial pressure of carbon dioxide) data collected using an equilibrator-infrared method (SUPER CO2 system from Sunburst Sensors). Ancillary data for calculation of air-sea CO2 fluxes include temperature, salinity, atmospheric CO2. 

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5. Copper oxide nanoparticle dissolution at alkaline pH is controlled by dissolved organic matter: influence of soil-derived organic matter, wheat, bacteria, and nanoparticle coating

   https://doi.org/10.1039/d0en00574f  

   Hortin, J. M.; Anderson, A. J.; Britt, D. W.; Jacobson, A. R.; McLean, J. E. (January 2020, Environmental Science: Nano)

   Dissolution of CuO nanoparticles, releasing Cu ions, is a primary mechanism of Cu interaction in the rooting zone of plants. CuO dissolution is sometimes incorrectly considered negligible at high pH, since complexation of Cu with dissolved organic matter may enhance nanoparticle dissolution. Therefore data on the effects of plant-microbial-soil interactions on nanoparticle dissolution, particularly in alkaline soils, are needed. Dissolution of CuO nanoparticles (100 mg kg −1 Cu) was studied in sand supplemented with factorial combinations of wheat growth, a root-colonizing bacterium, and saturated paste extracts (SPEs) from three alkaline, calcareous soils. In control sand systems with 3.34 mM Ca(NO 3 ) 2 solution, dissolved Cu was low (266 μg L −1 Cu). Addition of dissolved organic matter via wheat root metabolites and/or soil SPEs increased dissolved Cu to 795–6250 μg L −1 Cu. Dissolution was correlated with dissolved organic carbon ( R = 0.916, p < 0.0001). Ligands >3 kDa, presumably fulvic acid from the SPEs, complexed Cu driving solubility; the addition of plant exudates further increased solubility 1.5–3.5×. The root-colonizing bacterium decreased dissolved Cu in sand pore waters from planted systems due to metabolism of root exudates. Batch solubility studies (10 mg L −1 Cu) with the soil SPEs and defined solutions containing bicarbonate or fulvic acid confirmed elevated CuO nanoparticle solubility at >7.5 pH. Nanoparticle dissolution was suppressed in batch experiments compared to sand, via nanoparticle organic matter coating or homoconjugation of dissolved organic matter. Alterations of CuO nanoparticles by soil organic matter, plant exudates, and bacteria will affect dissolution and bioavailability of the CuO nanoparticles in alkaline soils. 

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