Browsing Geology by Author "Rodriguez-Blanco, Juan"
Now showing items 1-20 of 22
- Sort by:
- title
- issue date
- submit date
- Order:
- ascending
- descending
- Results:
- 5
- 10
- 20
- 40
- 60
- 80
- 100
-
ACC and vaterite as metastable intermediates in the solution based crystallization of CaCO3
Rodriguez-Blanco, Juan (Springer International Publishing, 2017)Amorphous calcium carbonate (ACC) and vaterite are not very common in abiotic systems, but they play a very significant role in biomineralization processes and are key in the global carbon cycle. Despite their importance, ... -
Amorphous dysprosium carbonate: characterization, stability, and crystallization pathways
Rodriguez-Blanco, Juan (2013)The crystallization of amorphous dysprosium carbonate (ADC) has been studied in air (21–750 °C) and in solution (21–250 °C). This poorly ordered precursor, Dy2(CO3)3·4H2O, was synthesized in solution at ambient temperature. ... -
Biomineralisation by earthworms - an investigation into the stability and distribution of amorphous calcium carbonate
Rodriguez-Blanco, Juan (2015)BACKGROUND: Many biominerals form from amorphous calcium carbonate (ACC), but this phase is highly unstable when synthesised in its pure form inorganically. Several species of earthworm secrete calcium carbonate granules ... -
Citrate Effects on Amorphous Calcium Carbonate (ACC) Structure, Stability, and Crystallization
Rodriguez-Blanco, Juan (2015)Understanding the role of citrate in the crystallization kinetics of amorphous calcium carbonate (ACC) is essential to explain the formation mechanisms, stabilities, surface properties, and morphologies of CaCO3 biominerals. ... -
Crystal structure of dicalcium sodium monohydrogen diarsenate hexahydrate, Ca2Na[HAsO4][AsO4] · 6H2O
Rodriguez-Blanco, Juan (De Gruyter, 2006)As2Ca2H13NaO14, triclinic, P1 (no. 2), a = 6.680(5) Å, b = 8.223(4) Å, c = 12.537(3) Å, = 73.46(5)°, = 78.89(4)°, = 87.47(5)°, V = 647.7 Å3 , Z = 2, Rgt(F) = 0.062, wRref(F2 ) = 0.197, T = 293 K. Source of ... -
The effect of aspartic acid and glycine on amorphous calcium carbonate (ACC) structure, stability and crystallization
Rodriguez-Blanco, Juan (Elsevier, 2014)The effect of organic molecules on CaCO3 crystallization, in particular on the formation of the initial amorphous calcium carbonate (ACC) phase, is poorly understood despite this knowledge being crucial for designing ... -
The effect of heating on the morphology of crystalline neodymium hydroxycarbonate, NdCO3OH
Rodriguez-Blanco, Juan (2014)The crystallization of hexagonal NdCO3OH through hydrothermal synthesis carried out at slow (reaching the desired temperature within 100 min) and quick (50 min) rates of heating but at variable temperatures (165–220ºC) are ... -
An experimental study of hydroxylbastnasite solubility in aqueous solutions at 25 °C
Rodriguez-Blanco, Juan (2016)The mobility of rare earth elements (REEs) in natural aqueous solutions is of increasing interest due to their application in numerous high-tech and renewable energy technologies (e.g., wind turbines and electric vehicles), ... -
Formation of calcium sulfate through the aggregation of sub-3 nanometre primary species
Rodriguez-Blanco, Juan (2016)The formation pathways of gypsum remain uncertain. Here, using truly in situ and fast time-resolved small-angle X-ray scattering, we quantify the four-stage solution-based nucleation and growth of gypsum (CaSO4·2H2O), an ... -
Inhibition of Calcite Growth: Combined Effects of Mg2+ and SO42–
Rodriguez-Blanco, Juan (2016)Magnesium and sulfate are each known to affect calcite growth and dissolution, but little is known about their combined effects on calcite growth rates. We grew calcite using the constant composition approach at ambient ... -
Is bicarbonate stable in and on the calcite surface?
Rodriguez-Blanco, Juan (2016)We have used density functional theory with the COSMO-RS implicit solvent model to predict the pKa for the deprotonation of bicarbonate to carbonate, i.e. HCO3− <=> CO32− + H+, when HCO3− is included in, and adsorbed on, ... -
Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate
Rodriguez-Blanco, Juan (2014)Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron and X-ray diffraction have been performed for a sample of magnesium-stabilised ACC, which was prepared with a Mg:Ca ... -
Organic synthesis on Mars by electrochemical reduction of CO2
Rodriguez-Blanco, Juan (American Association for the Advancement of Science, 2018)The sources and nature of organic carbon on Mars have been a subject of intense research. Steele et al. (2012) showed that 10 martian meteorites contain macromolecular carbon phases contained within pyroxene- and olivine-hosted ... -
Physicochemical and Additive Controls on the Multistep Precipitation Pathway of Gypsum
Rodriguez-Blanco, Juan (MDPI, 2017)Synchrotron-based small- and wide-angle X-ray scattering (SAXS/WAXS) was used to examine in situ the precipitation of gypsum (CaSO4·2H2O) from solution. We determined the role of (I) supersaturation, (II) temperature and ... -
Reaction pathways and textural aspects of the replacement of anhydrite by calcite at 25 °C
Rodriguez-Blanco, Juan (2017)The replacement of sulfate minerals by calcium carbonate polymorphs (carbonation) has important implications in various geological processes occurring in Earth surface environments. In this paper we report the results of ... -
Reaction Pathways toward the Formation of Bastnäsite: Replacement of Calcite by Rare Earth Carbonates
Rodriguez-Blanco, Juan (2021)The interaction of rare earth bearing (La, Nd, Dy) aqueous solutions with calcite crystals at ambient and hydrothermal conditions (25–220 °C) results in the solvent-mediated surface precipitation and subsequent pseudomorphic ... -
The role of amorphous precursors in the crystallization of La and Nd carbonates
Rodriguez-Blanco, Juan (2015)Crystalline La and Nd carbonates can be formed from poorly-ordered nanoparticulate precursors, termed amorphous lanthanum carbonate (ALC) and amorphous neodymium carbonate (ANC). When reacted in air or in aqueous solutions ... -
The role of REE3+ in the crystallization of lanthanites
Rodriguez-Blanco, Juan (2014)The formation of crystalline rare earth element (REE) (e.g. La, Ce, Pr, Nd) carbonates from aqueous solutions was examined at ambient temperature using UV-Vis spectrophotometry, combined with X-ray diffraction, high-resolution ... -
A route for the direct crystallization of dolomite
Rodriguez-Blanco, Juan (2015)The direct crystallization of dolomite from an aqueous solution at temperatures between 60–220 °C was followed in situ through time-resolved synchrotron-based energy-dispersive X-ray diffraction combined with offline ... -
Salinity-Dependent Adhesion Response Properties of Aluminosilicate (K-Feldspar) Surfaces
Rodriguez-Blanco, Juan (2017)Flooding sandstone oil reservoirs with low salinity water can lead to a significant increase in oil recovery, a phenomenon called “the low salinity effect”. Although there are many factors that contribute to this response, ...