Search results for " sequestrati."
showing 10 items of 109 documents
Sequestration of alkyltin(IV) cations by complexation with amino-polycarboxylic chelating agents
2013
Abstract The binding capacity of four amino-polycarboxylic ligands (APCs) [nitrilotriacetate (NTA), ethylenediamine- N , N , N′ , N′ -tetraacetate (EDTA), (S,S)-ethylenediamine- N , N ′-disuccinic acid (S,S-EDDS) and diethylenetriamine- N , N , N′ , N″ , N″ -pentaacetate (DTPA)] towards mono-, di- and tri-alkyltin(IV) cations [(CH 3 )Sn 3 + , (CH 3 ) 2 Sn 2 + , (C 2 H 5 ) 2 Sn 2 + , (CH 3 ) 3 Sn + or (C 2 H 5 ) 3 Sn + ] was studied, in aqueous solutions, by ISE-H + potentiometry, at I = 0.1 mol L − 1 (NaCl) and at T = 298.15 K. In all the systems R x Sn (4 − x)+ − APC (R = CH 3 or C 2 H 5 ) a strong 1:1 species is formed together with protonated, hydroxo and dinuclear complexes. The valu…
Uranium(VI) sequestration by polyacrylic and fulvic acids in aqueous solution
2011
Stability data on the formation of dioxouranium(VI) species with polyacrylic (PAA) and fulvic acids (FA) are reported with the aim to define quantitatively the sequestering capacity of these high molecular weight synthetic and naturally occurring ligands toward uranium(VI), in aqueous solution. Investigations were carried out at t = 25 °C in NaCl medium at different ionic strengths and in absence of supporting electrolyte for uranyl–fulvate (\( {{\text{UO}}_{2}}^{2+} \)–FA) and uranyl–polyacrylate (\( {{\text{UO}}_{ 2}}^{ 2+ } \)–PAA, PAA MW 2 kDa) systems, respectively. The experimental data are consistent with the following speciation models for the two systems investigated: (i) UO2(FA1),…
Relief and calcium from gypsum as key factors for net inorganic carbon accumulation in soils of a semiarid Mediterranean environment
2021
Abstract In semiarid environments, the total inorganic carbon (TIC) in soil may contribute to the total carbon (C) pool more than the total organic C pool (TOC), thus playing a key role in storing atmospheric CO2. However, due to the different origin pathways of soil carbonates, not all of the TIC pool can be accounted for CO2 sequestration. Indeed, the inorganic C can be accounted for a net sink of CO2 only when calcium (Ca2+) forming carbonates originate from non-carbonate minerals (atmogenic inorganic C, AIC). The aim of this study carried out in a gypsiferous area is to investigate the dissolution of Ca2+ that comes from gypsum (CaSO4·2H2O) in the formation of soil atmogenic carbonates …
The role of hydrology on enhanced weathering for carbon sequestration I. Modeling rock-dissolution reactions coupled to plant, soil moisture, and car…
2021
Abstract Enhanced Weathering (EW) resulting from soil amendment with highly reactive silicate minerals is regarded as one of the most effective techniques for carbon sequestration. While in laboratory conditions silicate minerals dissolution rates are well characterized, in field conditions the rate of the dissolution reaction is more difficult to predict, not least because it interacts with soil, plant, and hydrologic processes. Here we present a dynamic mass balance model connecting biogeochemical and ecohydrological dynamics to shed light on these intertwined processes involved in EW. We focus on the silicate mineral olivine, for its faster laboratory dissolution rate, and pay particular…
Long-term Additions of Organic Amendments in a Loire Valley Vineyard. I. Effects on Properties of a Calcareous Sandy Soil
2008
International audience; A long-term experiment (28 years) was conducted to Study the effects of various organic amendments oil physical, chemical, and biological properties of a sandy vineyard soil. Annual applications of either crushed pruned vine-wood (2 t/ha fresh wt), cattle manure (10 and 20 t/ha fresh wt.), or spent mushroom compost (8 and 16 t/ha fresh wt) were compared to all unamended treatment, In plots unamended for 28 years, total organic C (TOC) showed a slow and limited decrease (19%). For the highest rates of exogenous organic amendments, the increase in TOC reached a saturation Value after 20 years and carbon (C) sequestered after 28 years reached 30 Mg/ha. Final predicted T…
In situ polymerization of soil organic matter by oxidative biomimetic catalysis
2017
Abstract Background Agricultural practices that enhance organic matter content in soil can play a central role in sequestering soil organic carbon (SOC) and reducing greenhouse gases emissions. Methods We used a water-soluble iron-porphyrin to catalyze directly in situ oxidative polymerization of soil organic matter in the presence of H2O2 oxidant, with the aim to enhance OC stabilization, and, consequently, reduce CO2 emissions from soil. The occurred SOC stabilization was assessed by monitoring soil aggregate stability, OC distribution in water-soluble aggregates, soil respiration, and extraction yields of humic and fulvic acids. Results Soil treatment with H2O2 and iron-porphyrin increas…
Interactions of Dioxouranium(VI) with Amines in Aqueous Solution
2010
The interaction of the dioxouranium(VI) ion with five low molecular weight polyamines (ethylenediamine, putrescine, cadaverine, spermidine, and spermine) and with poly(allyl)amine (15 kDa) was studied potentiometrically (ISE-H + glass electrode) at T ) 298.15 K. Investigations were carried out in NaNO3 ionic medium, at I ) 0.1 mol · L -1 (and 0.5 mol · L -1 for poly(allyl)amine only), in the pH range 3.5 to 5.5, before the formation of uranyl insoluble species. The results gave evidence for the formation of two species, namely, UO2L 2+ and UO2L(OH) + for the diamine systems (ethylenediamine, putrescine, cadaverine), UO2L 2+ and UO2LH 3+ for spermidine, and UO2LH 3+ and UO2LH2 4+ for spermin…
Sensitivity of L-band vegetation optical depth to carbon stocks in tropical forests: a comparison to higher frequencies and optical indices
2019
Supplementary data to this article can be found online at https://doi.org/10.1016/j.rse.2019.111303. Monitoring vegetation carbon in tropical regions is essential to the global carbon assessment and to evaluate the actions oriented to the reduction of forest degradation. Mainly, satellite optical vegetation indices and LiDAR data have been used to this purpose. These two techniques are limited by cloud cover and are sensitive only to the top of vegetation. In addition, the vegetation attenuation to the soil microwave emission, represented by the vegetation optical depth (VOD), has been applied for biomass estimation using frequencies ranging from 4 to 30¿GHz (C- to K-bands). Atmosphere is t…
Carbon sequestration potential and soil characteristics of various land use systems in arid region
2019
Abstract Soils contain one of the largest carbon (C) pools in the biosphere with the greatest potential of C sequestration to mitigate climate change impacts. The present study aimed at comparing C sequestration potential of various land use systems including forestlands, croplands, agroforests, and orchards in the arid region of Pakistan. Soil samples from the layers of 0–20, 20–40, 40–60, and 60–80 cm depths were collected and analysed for soil physico-chemical properties namely texture, pH, EC, NPK-soil, organic matter (SOM), and soil organic C (SOC). Additionally, the above and below ground plant biomass and C contents were estimated. Results revealed that the highest C sequestration po…
Microtomographic Quantification of Hydraulic Clay Mineral Displacement Effects During a CO2 Sequestration Experiment with Saline Aquifer Sandstone
2013
We combined a noninvasive tomographic imaging technique with an invasive open-system core-flooding experiment and compared the results of the pre- and postflooded states of an experimental sandstone core sample from an ongoing field trial for carbon dioxide geosequestration. For the experiment, a rock core sample of 80 mL volume was taken from the 629 m Stuttgart Formation storage domain of a saline sandstone aquifer at the CCS research pilot plant Ketzin, Germany. Supercritical carbon dioxide and synthetical brine were injected under in situ reservoir p/T-conditions at an average flow rate of 0.1 mL/min for 256 h. X-ray computed microtomographic imaging was carried out before and after the…