Elution profile of cationic and anionic adsorbate from exhausted adsorbent using solvent desorption

Present invention involves to study the elution profile of anionic and cationic compounds from exhausted adsorbents using various eluents. Batch elution studies of anionic components like Congo Red dye and Carbonate ion; and cationic compounds such as Methylene blue dye and Cadmium metal from previously used naturally prepared adsorbents i.e. Gulmohar (Delonix regia) leaf powder - GLP; and Neem (Azadirachta indica) leaf powder – NLP and their derivatives were conducted. Different eluents used for batch study were various acids and alkaline solution having various concentration and solvents having different functional groups in seven sorption-desorption cycles. The batch data were accessed by kinetic models (Pseudo First-, Pseudo Second-order, Intra-partice and Elovic equation). Column elution experiments of Congo red and Cadmium from NLP and activated charcoal from NLP (AC-NLP) respectively was performed using selected eluent. Sorption and elution process plots and parameters for seven sorption–desorption cycles were evaluated and discussed. Plots of life cycle indicating activity-indicator equations were drawn, and their parameters were calculated and mentioned. From desorption efficiencies, it revealed that desorption exploration is predominately depends upon pH factor.

Southern Ocean contribution to both steps in deglacial atmospheric CO2 rise

The transfer of vast amounts of carbon from a deep oceanic reservoir to the atmosphere is considered to be a dominant driver of the deglacial rise in atmospheric CO2. Paleoceanographic reconstructions reveal evidence for the existence of CO2-rich waters in the mid to deep Southern Ocean. These water masses ventilate to the atmosphere south of the Polar Front, releasing CO2 prior to the formation and subduction of intermediate-waters. Changes in the amount of CO2 in the sea water directly affect the oceanic carbon chemistry system. Here we present B/Ca ratios, a proxy for delta carbonate ion concentrations Δ[CO32−], and stable isotopes (δ13C) from benthic foraminifera from a sediment core bathed in Antarctic Intermediate Water (AAIW), offshore New Zealand in the Southwest Pacific. We find two transient intervals of rising [CO32−] and δ13C that that are consistent with the release of CO2 via the Southern Ocean. These intervals coincide with the two pulses in rising atmospheric CO2 at ~ 17.5–14.3 ka and 12.9–11.1 ka. Our results lend support for the release of sequestered CO2 from the deep ocean to surface and atmospheric reservoirs during the last deglaciation, although further work is required to pin down the detailed carbon transfer pathways.

Ecological, Oceanographic and Temperature Controls on the Incorporation of Trace Elements into Globigerina Bulloides and Globoconella Inflata in the Southwest Pacific Ocean

<p>Trace element ratios (Mg/Ca, Al/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) measured by laser ablation inductively coupled plasma mass spectrometry plus and test weight and size data are presented for two planktonic foraminiferal species, Globigerina bulloides and Globoconella inflata. These data will be used to investigate the potential of Mg/Ca ocean thermometry and other trace element proxies of past ocean chemistry using these species. Foraminifera were sampled from core-top sediments from 10 sites in the Southwest Pacific Ocean, east of New Zealand, spanning latitudes of c.33' to 54' S and temperatures of 6-19' C at 75-300 m water depth. Mg/Ca in G. bulloides correlates strongly with observed water temperatures at 200 m depth and yields a new calibration of Mg/Ca = 0.941 exp 0.0693*T (r2 = 0.95). When G. bulloides Mg/Ca data from this study are combined with previously published data for this species, a calibration of Mg/Ca = 0.998 exp 0.066*T (r2 = 0.97) is defined. Significant variability of Mg/Ca values (20-30%) was found for the four largest chambers of G. bulloides with the final chamber consistently recording the lowest Mg/Ca values. This is interpreted to reflect changes in the depth habitat towards the end of the life cycle of G. bulloides. Levels of A1 and the micronutrients Mn and Zn in G. bulloides were found to differ significantly between Subtropical and Subantarctic Water masses, suggesting these elements can potentially be used as water mass tracers. No clear relationship between Mg/Ca and temperature was observed for G.inflata. This is interpreted, in part, to reflect the ecological niche that G. inflata occupies at the base of the thermocline, coupled with the impact of heavy secondary calcite which lowers Mg/Ca values. A correlation between size normalized test weight, water temperature and seawater carbonate ion concentration is observed for G. bulloides suggesting a modern calibration that could be potentially applied for paleoceanographic reconstructions of ocean water temperature and carbonate ion concentrations. No correlation between temperature or carbonate ion was found with size normalized G. inflata test weights. However, a bimodal population of G. inflata test weights indicates a possible link between high levels of chlorophyll-a in surface waters and light G. inflata tests. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and solution-based techniques for measuring Mg/Ca in G. bulloides yield compatible results. However, this is possible only when minimal dissolution of test calcite has occurred during the reductive and dilute acid leaching stages of cleaning prior to solution analysis, or, if only the older three visible chambers are used for LA-ICP-MS analysis. LA-ICP-MS analysis is an effective method for measuring trace element/Ca values in foraminifera, especially for small sample sizes, and enables the test to be used for further geochemical analysis (e.g. boron or carbon/oxygen stable isotope analysis).</p>

Ecological, Oceanographic and Temperature Controls on the Incorporation of Trace Elements into Globigerina Bulloides and Globoconella Inflata in the Southwest Pacific Ocean

<p>Trace element ratios (Mg/Ca, Al/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) measured by laser ablation inductively coupled plasma mass spectrometry plus and test weight and size data are presented for two planktonic foraminiferal species, Globigerina bulloides and Globoconella inflata. These data will be used to investigate the potential of Mg/Ca ocean thermometry and other trace element proxies of past ocean chemistry using these species. Foraminifera were sampled from core-top sediments from 10 sites in the Southwest Pacific Ocean, east of New Zealand, spanning latitudes of c.33' to 54' S and temperatures of 6-19' C at 75-300 m water depth. Mg/Ca in G. bulloides correlates strongly with observed water temperatures at 200 m depth and yields a new calibration of Mg/Ca = 0.941 exp 0.0693*T (r2 = 0.95). When G. bulloides Mg/Ca data from this study are combined with previously published data for this species, a calibration of Mg/Ca = 0.998 exp 0.066*T (r2 = 0.97) is defined. Significant variability of Mg/Ca values (20-30%) was found for the four largest chambers of G. bulloides with the final chamber consistently recording the lowest Mg/Ca values. This is interpreted to reflect changes in the depth habitat towards the end of the life cycle of G. bulloides. Levels of A1 and the micronutrients Mn and Zn in G. bulloides were found to differ significantly between Subtropical and Subantarctic Water masses, suggesting these elements can potentially be used as water mass tracers. No clear relationship between Mg/Ca and temperature was observed for G.inflata. This is interpreted, in part, to reflect the ecological niche that G. inflata occupies at the base of the thermocline, coupled with the impact of heavy secondary calcite which lowers Mg/Ca values. A correlation between size normalized test weight, water temperature and seawater carbonate ion concentration is observed for G. bulloides suggesting a modern calibration that could be potentially applied for paleoceanographic reconstructions of ocean water temperature and carbonate ion concentrations. No correlation between temperature or carbonate ion was found with size normalized G. inflata test weights. However, a bimodal population of G. inflata test weights indicates a possible link between high levels of chlorophyll-a in surface waters and light G. inflata tests. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and solution-based techniques for measuring Mg/Ca in G. bulloides yield compatible results. However, this is possible only when minimal dissolution of test calcite has occurred during the reductive and dilute acid leaching stages of cleaning prior to solution analysis, or, if only the older three visible chambers are used for LA-ICP-MS analysis. LA-ICP-MS analysis is an effective method for measuring trace element/Ca values in foraminifera, especially for small sample sizes, and enables the test to be used for further geochemical analysis (e.g. boron or carbon/oxygen stable isotope analysis).</p>

Fabrication of an All-Solid-State Carbonate Ion-Selective Electrode with Carbon Film as Transducer and Its Preliminary Application in Deep-Sea Hydrothermal Field Exploration

Real-time measurements of carbonate ion concentrations in the ocean are critical to advancing marine environmental monitoring and research into deep-sea hydrothermal activity. Herein, we report the first example of deep-sea hydrothermal field exploration using a carbonate ion-selective electrode (ISE). The novel carbonate ISE was composed of a Ni wire as substrate, carbon film as transducers and carbonate-selective membrane layers. This paper describes the preparation process of the electrode and characterises its performance via scanning electron microscopy (SEM) and electrochemical analysis. The detection limit of the electrode for CO32− is 2.821 × 10−6 mol/L, the linear response range is 1.0 × 10−5–1.0 × 10−1 mol/L and the Nernst slope was −30.4 mV/decade. In April 2021, the carbonate ISE was mounted on multi-parameter sensors with pH and Eh (redox) electrodes for the search of hydrothermal activity at the Southwest Indian Ridge. The simultaneous potential anomalies appeared at this carbonate electrode with the pH and Eh electrodes when passing through the hydrothermal field. The study of the hydrothermal field was supported by the in situ camera video and the sulphide samples. Additionally, the carbonate electrode provides enhanced information of water chemistry for the study of the hydrothermal field.

PyCO2SYS v1.7: marine carbonate system calculations in Python

Oceanic dissolved inorganic carbon (TC) is the largest pool of carbon that interacts considerably with the atmosphere on human timescales. Oceanic TC is increasing through uptake of anthropogenic carbon dioxide (CO2), and seawater pH is decreasing as a consequence. Both the exchange of CO2 between ocean and atmosphere and the pH response are governed by a set of parameters that interact through chemical equilibria, collectively known as the marine carbonate system. To investigate these processes, at least two of the marine carbonate system's parameters are typically measured – most commonly, two from TC, total alkalinity (AT), pH, and seawater CO2 fugacity (fCO2; or its partial pressure, pCO2, or its dry-air mole fraction, xCO2) – from which the remaining parameters can be calculated and the equilibrium state of seawater solved. Several software tools exist to carry out these calculations, but no fully functional and rigorously validated tool was previously available for Python, a popular scientific programming language. Here, we present PyCO2SYS, a Python package intended to fill this capability gap. We describe the elements of PyCO2SYS that have been inherited from the existing CO2SYS family of software and explain subsequent adjustments and improvements. For example, PyCO2SYS uses automatic differentiation to solve the marine carbonate system and calculate chemical buffer factors, ensuring that the effect of every solute and reaction is accurately included in all its results. We validate PyCO2SYS with internal consistency tests and comparisons against other software, showing that PyCO2SYS produces results that are either virtually identical or different for known reasons, with the differences negligible for all practical purposes. We discuss new insights that arose during the development process, for example that the marine carbonate system cannot be unambiguously solved from the total alkalinity and carbonate ion parameter pair. Finally, we consider potential future developments to PyCO2SYS and discuss the outlook for this and other software for solving the marine carbonate system. The code for PyCO2SYS is distributed via GitHub (https://github.com/mvdh7/PyCO2SYS) under the GNU General Public License v3, archived on Zenodo (Humphreys et al., 2021), and documented online (https://PyCO2SYS.readthedocs.io).

First-Principle Studies of the Vibrational Properties of Carbonates under Pressure

Using the density functional theory with the hybrid functional B3LYP and the basis of localized orbitals of the CRYSTAL17 program code, the dependences of the wavenumbers of normal long-wave ν vibrations on the P(GPa) pressure ν(cm−1) = ν0 + (dv/dP)·P + (d2v/dP2)·P and structural parameters R(Å) (R: a, b, c, RM-O, RC-O): ν(cm−1) = ν0 + (dv/dR) − (R − R0) were calculated. Calculations were made for crystals with the structure of calcite (MgCO3, ZnCO3, CdCO3), dolomite (CaMg(CO3)2, CdMg(CO3)2, CaZn(CO3)2) and aragonite (SrCO3, BaCO3, PbCO3). A comparison with the experimental data showed that the derivatives can be used to determine the P pressures, a, b, c lattice constants and the RM-O metal-oxygen, and the RC-O carbon-oxygen interatomic distances from the known Δν shifts. It was found that, with the increasing pressure, the lattice constants and distances R decrease, and the wavenumbers increase with velocities the more, the higher the ν0 is. The exceptions were individual low-frequency lattice modes and out-of-plane vibrations of the v2-type carbonate ion, for which the dependences are either nonlinear or have negative dv/dP (positive dv/dR) derivatives. The reason for this lies in the properties of chemical bonding and the nature of atomic displacements during these vibrations, which cause a decrease in RM-O and an increase in RC-O.