Direct imaging of coupled dissolution-precipitation and growth processes on calcite exposed to chromium-rich fluids

Guren, Marthe Grønlie; Putnis, Christine V.; Montes-Hernandez, German; H, King; Renard, François

doi:10.1016/j.chemgeo.2020.119770

Cited by 24 publications

(16 citation statements)

References 33 publications

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“…As such, the number of elements upon which v can be evaluated decreases sharply over time, none of these structures being detected for t > 20 min. The results listed in Table 1 show that the mean and standard deviation of v monotonically decrease in time, the observed values being consistent with those documented in previous experiments concerning calcite {104} and MilliQ water (Guren et al 2020;Harstad and Stipp 2007).…”

Section: Evaluation Of the Pit Spreading Ratesupporting

confidence: 89%

“…This could suggest that local supersaturation of the boundary layer has not been attained yet. Otherwise, this could also be ascribed to the effect of the scanning probe on the investigated area, as the AFM tip may displace precipitates that are weakly connected to the surface (see also Guren et al 2020, andRenard et al 2019). Spreading of MP 1 takes place only along the acute step and is characterized by a lower extent than what can be noted for MP 2 and MP 3 .…”

Section: Evolution Of Calcite Dissolution Patternsmentioning

confidence: 99%

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Statistical Characterization of Heterogeneous Dissolution Rates of Calcite from In situ and Real-Time AFM Imaging

et al. 2021

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The evolution of the surface topography of a calcite crystal subject to dissolution is documented through in situ real-time imaging obtained via atomic force microscopy (AFM). The dissolution process takes place by exposing the crystal surface to deionized water. AFM data allow detection of nucleation and expansion of mono- and multilayer rhombic etch pits and are employed to estimate the spreading rate of these structures. Spatially heterogeneous distributions of local dissolution rate are evaluated from the difference between topographic measurements taken at prescribed time intervals. We rest on a stochastic framework of analysis viewing the dissolution rate as a generalized sub-Gaussian (GSG) spatially correlated random process. Our analysis yields: (i) a quantitative assessment of the temporal evolution of the statistics of the dissolution rates as well as their spatial increments; (ii) a characterization of the degree of spatial correlation of dissolution rates and of the way this is linked to the various mechanisms involved in the dissolution process and highlighted through the experimental evidences. Our results indicate that the parameters driving the statistics of the GSG distribution and the spreading rate of the multilayer pits display a similar trend in time, thus suggesting that the evolution of these structures imprints the statistical features of local dissolution rates. Article Highlights We investigate dynamics of dissolution patterns on a calcite crystal in contact with deionized water via AFM imaging Temporal behavior of parameters of our statistical model is consistent with surface pattern evolution A nested model for the spatial correlation of rates embeds multiple mechanisms driving dissolution rate.

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Section: Evaluation Of the Pit Spreading Ratesupporting

confidence: 89%

Section: Evolution Of Calcite Dissolution Patternsmentioning

confidence: 99%

Statistical Characterization of Heterogeneous Dissolution Rates of Calcite from In situ and Real-Time AFM Imaging

et al. 2021

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“…Thus, while in the latter case, [Pb]48h approaches 3mg/L, a slower Pb-removal rate during the interaction with calcite results in [Pb] (Figures 7a and 7b) supports a dissolution-precipitation process as the main mechanism responsible for Pb removal during this interaction. As explained in the introduction section, dissolution-precipitation are main operating mechanism that leads to effective removal of a variety of dissolved pollutants from aqueous solutions interacting with calcite [37,55,58]. The dissolution-precipitation process that operates during the interaction of Pb-bearing solutions and calcite has similar characteristics to those of the gypsum dissolution-anglesite precipitation one described in 4.1.…”

Section: Effectiveness Of Calcite As Pb Scavengermentioning

confidence: 95%

“…In fact, coupled dissolution-reactions that involve different sulfate and carbonate minerals are considered an effective long-term way of removing inorganic pollutants from natural water and wastewaters [48][49][50][51] as well as reducing the increase atmospheric CO2 [52,53]. Indeed, in situ AFM imagining has unraveled that coupled dissolution-crystallization reactions that involve calcite effectively remove pollutants like manganese [54], cadmium [37], lead [55], phosphate [56,57], and chromate [58] from aqueous solutions. Similarly, coupled dissolution-crystallization reactions that occur during gypsum-aqueous solution interaction can result in the sequestration of dissolved components like barium and strontium [59], lead [60], arsenate [61], phosphate [62,63] and carbonate [64] through their immobilization in the structure of new phase.…”

Section: Introductionmentioning

confidence: 99%

Removal of Pb from Water: the Effectiveness of Gypsum and Calcite Mixtures

Llera¹,

Jiménez²,

Fernández-Dı́az³

2020

Preprint

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Anthropogenic lead pollution is an environmental problem that threatens the quality of soils and waters and endangers living organisms in numerous surface and subsurface habitats. Lead coprecipitation on mineral surfaces through dissolution-recrystallization processes has long term effects on lead bioavailability. Gypsum and calcite are among the most abundant and reactive rock forming minerals present in numerous geological settings. In this work, we study the interaction of slightly acidic (pHi = 5.5) Pb-bearing aqueous solutions ([Pb]i = 1 mM and 10 mM) with crystals of gypsum and /or calcite under atmospheric conditions. This interaction results in a reduction of the concentration of lead in the liquid phase due to the precipitation of newly formed Pb-bearing solid phases. The extent of this Pb removal mainly depends on the nature of the primary mineral phase involved in the interaction. Thus, when gypsum is the only solid phase initially present in the system the Pb-bearing liquid-gypsum interaction results in Pb removals in the 98-99.8 % range, regardless of [Pb]i. In contrast, when the interaction takes place with calcite, Pb removal strongly depends on [Pb]i. It reaches 99% when [Pb]i = 1 mM while it is much more modest (⁓13%) when [Pb]i = 10 mM. Interestingly, Pb-removal is maximized for both [Pb]i (99.9 % for solutions with [Pb]i = 10 mM and 99.7% for solutions with [Pb]i = 1 mM) when Pb-polluted solutions simultaneously interact with gypsum and calcite crystals. Despite the large Pb removals found in most of the cases studied, the final Pb concentration ([Pb]f) in the liquid phase always is well above the maximum permitted in drinking water (0.1 ppm), with the minimum ([Pb]f = 0.7 ppm) being obtained for solutions with [Pb]i =1 mM after their interaction with mixtures of gypsum and calcite crystals. This result suggests that integrating the use of mixtures of gypsum-calcite crystals might help to develop more efficient strategies for in-situ decontaminating Pb-polluted waters through mineral coprecipitation processes.

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“…In fact, coupled dissolution reactions that involve different sulfate and carbonate minerals are considered an effective long-term way of removing inorganic pollutants from natural water and wastewaters [48][49][50][51] as well as reducing the increase atmospheric CO 2 [52,53]. Indeed, in situ AFM imaging has unraveled that coupled dissolution-crystallization reactions that involve calcite effectively remove pollutants like manganese [54], cadmium [37], lead [55], phosphate [56,57], and chromate [58] from aqueous solutions. Similarly, coupled dissolution-crystallization reactions that occur during gypsum-aqueous solution interaction can result in the sequestration of dissolved components like barium and strontium [59], lead [60], arsenate [61], phosphate [62,63], and carbonate [64] through their immobilization in the structure of new phase.…”

Section: Introductionmentioning

confidence: 99%

Removal of Pb from Water: The Effectiveness of Gypsum and Calcite Mixtures

2021

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Anthropogenic lead pollution is an environmental problem that threatens the quality of soils and waters and endangers living organisms in numerous surface and subsurface habitats. Lead coprecipitation on mineral surfaces through dissolution-recrystallization processes has long-term effects on lead bioavailability. Gypsum and calcite are among the most abundant and reactive rock forming minerals present in numerous geological settings. In this work, we studied the interaction of slightly acidic (pHi = 5.5) Pb-bearing aqueous solutions ([Pb]i = 1 and 10 mM) with crystals of gypsum and/or calcite under atmospheric conditions. This interaction resulted in a reduction of the concentration of lead in the liquid phase due to the precipitation of newly formed Pb-bearing solid phases. The extent of this Pb removal mainly depended on the nature of the primary mineral phase involved in the interaction. Thus, when gypsum was the only solid phase initially present in the system, the Pb-bearing liquid-gypsum interaction resulted in Pb removals in the 98–99.8% range, regardless of [Pb]i. In contrast, when the interaction took place with calcite, Pb removal strongly depended on [Pb]i. It reached 99% when [Pb]i = 1 mM, while it was much more modest (~13%) when [Pb]i = 10 mM. Interestingly, Pb-removal was maximized for both [Pb]i (99.9% for solutions with [Pb]i = 10 mM and 99.7% for solutions with [Pb]i = 1 mM) when Pb-polluted solutions simultaneously interacted with gypsum and calcite crystals. Despite the large Pb removals found in most of the cases studied, the final Pb concentration ([Pb]f) in the liquid phase was always well above the maximum permitted in drinking water (0.01 ppm), with the minimum ([Pb]f = 0.7 ppm) being obtained for solutions with [Pb]i = 1 mM after their interaction with mixtures of gypsum and calcite crystals. This result suggests that integrating the use of mixtures of gypsum-calcite crystals might help to develop more efficient strategies for in-situ decontaminating Pb-polluted waters through mineral coprecipitation processes.

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Direct imaging of coupled dissolution-precipitation and growth processes on calcite exposed to chromium-rich fluids

Cited by 24 publications

References 33 publications

Statistical Characterization of Heterogeneous Dissolution Rates of Calcite from In situ and Real-Time AFM Imaging

Statistical Characterization of Heterogeneous Dissolution Rates of Calcite from In situ and Real-Time AFM Imaging

Removal of Pb from Water: the Effectiveness of Gypsum and Calcite Mixtures

Removal of Pb from Water: The Effectiveness of Gypsum and Calcite Mixtures

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