Josep M. Soler

Spanish National Research Council | CSIC · IDAEA-CSIC, Dept. of Geosciences, Barcelona

Geologic CO2 storage is projected to play a key role in mitigating the climate change crisis. Changes in pore structure and hydraulic properties are likely to occur in carbonate rocks when they interact with CO2 as an acid-producing agent, potentially affecting CO2 flow and storage behavior in the subsurface. Here, we combine laboratory experiments...

Porosity is a key parameter controlling the physico-chemical behavior of porous rocks. Digital rock physics offers a unique technique for imaging the inherently heterogeneous rock microstructure at fine spatial resolutions and its computational reconstruction, through which a better understanding and prediction of the rock behavior can be achieved....

Porosity and permeability changes are anticipated when carbonate rocks are percolated with and dissolved by acidic fluids. The ability to predict the location, extent, and impact of these changes could benefit acid-relevant operations in carbonate rocks, specifically CO2 storage by improving our estimates of CO2 flow and storage performance in the...

CO2 storage in carbonate aquifers is a way to mitigate atmospheric CO2 emissions, but ‎it leads to acid-producing reactions that may induce alterations in the rock pore structure and ‎hydromechanical properties. To gain a better understanding of these changes in rock properties, ‎percolation experiments under constant flow-rate conditions with (i)...

The REPRO-TDE test was performed at a depth of about 400 m in the ONKALO underground research facility in Finland. Synthetic groundwater containing radionuclide tracers (HTO, Cl-36, Na-22, Ba-133, Cs-134) was circulated for about four years in a packed-off interval of the injection borehole. Tracer activities were additionally monitored in two obse...

The Aran Valley in Catalonia (Spain) was the site of large-scale Zn, Pb, Cu, Fe, and Ag mining from the late 19th century until approximately 1950. Although mining activities ceased over 70 years ago, some of the abandoned mining relics (e.g. tunnels, processing facilities, and tailings dumps) exhibit elevated concentrations of metals in the associ...

Geological carbon storage is one of the technologies required to arrive at the ambitious yet realistic net-zero emission target and climate change neutrality. Injected CO2 in geological formations acidifies the resident brine, inducing chemical reactions with the minerals. Reactions may alter the hydraulic and mechanical properties of the rock and...

Our study focused on the leaching processes in soil contaminated with hexavalent chromium (Cr(VI)), traced to industrial waste from a disused site and resulting in groundwater contamination. Mineral and geochemical characterization of the soil by means of XRD, SEM-EDS, total digestion and sequential extractions revealed that the main Cr content was...

CO2 geological storage in deep rock formations is a possible strategy to mitigate the atmospheric CO2 concentration. In storage sites, CO2 is injected through wells. The space between the metal casing of the wellbore and the host rock is filled with Portland cement in which micro-fractures on flow paths between cement and rock may originate. It has...

Our study focused on the leaching processes in soil contaminated with hexavalent chromium (Cr(VI)), traced to industrial waste from a disused site and resulting in groundwater contamination. Mineral and geochemical characterization of the soil by means of XRD, SEM-EDS, total digestion and sequential extractions revealed that the main Cr content was...

Large-scale Zn, Pb, Cu, Fe and Ag mining ceased over 70 years ago in the Aran Valley (Catalonia, Spain). Some of the abandoned mining relics (e.g. tunnels, processing facilities and tailings dumps) exhibit elevated concentrations of metals in the associated water systems, thus posing a health risk in the neighboring ecosystem. In this study, the la...

This study shows a comparison and analysis of results from a modelling exercise concerning a field experiment involving the transport and retention of different radionuclide tracers in crystalline rock. This exercise was performed within the SKB Task Force on Modelling of Groundwater Flow and Transport of Solutes (Task Force GWFTS). Task 9B of the...

Cobalt demand is increasing due to its key role in the transition to clean energies. Although the main Co ores are the sediment-hosted stratiform copper deposits of the Democratic Republic of the Congo, Co is also a by-product of Ni–Co laterite deposits, where Co extraction efficiency depends, among other factors, on the correct identification of C...

In this study we tested the dissolution kinetics of three garnierite types (serpentine-, talc- and sepiolite-dominated) at pH of 3 and 5 and room temperature by means of flow-through experiments. The samples selected for the study cover a wide range of mineralogical composition (Xtalc, between 0.34 and 0.78) and Ni content (between 0.8 and 2.4 atom...

CO2 storage in deep geological formations (e.g., saline aquifers) is essential for global warming ‎mitigation. Storage of large amounts of CO2 in the saline aquifers results in acidification of the resident ‎brine, inducing chemical reactions that change the pore structure of the host rock. Hence, the ‎hydromechanical properties of the host rock ar...

Groundwaters of the Chaco-Pampean Plain in Argentina are contaminated by arsenic released from weathered volcaniclastic loess sediments. To better understand As release, the dissolution of three loessial materials (loess, volcanic glass shards (VGS) and volcanic ash) that make up the sediments was studied at pH 2–12 and 10–50 °C using flow-through...

The SKB GroundWater Flow and Transport of Solutes Task Force is an international forum in the area of conceptual and numerical modeling of groundwater flow and solute transport in fractured rocks relevant for the deep geological disposal of radioactive waste. Two in situ matrix diffusion experiments in crystalline rock (gneiss) were performed at PO...

To better understand the geochemical alteration of the interface between wellbore Portland cement and rock because of potential leakage during CO2 storage operations, we performed percolation experiments using three solid cores each made of two half-cylinders, one of hydrated Portland cement and the other of calcareous rock (limestone, marl or sand...

Adverse impacts of mine tailings on water and sediments quality are major worldwide environmental problems. Due to the environmental issues associated with the deposition of mine tailings on land, a controversial discussed alternative is submarine tailings disposal (STD). However, Fe(III) bioreduction of iron oxides (e.g., magnetite) in the tailing...

AMD is the acidic discharge generated by the oxidation of sulfide minerals from active or disused mine workings and contains high concentrations of toxic metals and sulfuric acid. Host rocks and concrete-based infrastructures in permanent contact with AMD are highly vulnerable to the geochemical processes caused by acidity (e.g. concrete corrosion)...

Percolation experiments, using columns filled with alternating layers of hydrated Portland cement and crushed sedimentary rocks, were conducted at PCO2 = 10 bar and 60 °C. Limestone, sandstone and marl were representative of reservoir and cap rocks for geologic CO2 storage. The injected solution was at equilibrium with gypsum and equilibrated with...

Nickel laterite deposits developed on ultramafic rocks have traditionally been a significant source of Ni and Co and recently of Sc. Although the Loma de Hierro deposit (Venezuela) has been in operation for more than 50 years, it lacks detailed studies on the mineralogical and geochemical composition of the lateritic profile. In this study, we pres...

Portland cement and concrete are major components of the engineered barrier system and of structural supports in different concepts for the geological disposal of low- and intermediate-level radioactive waste, high-level waste and spent fuel. The interaction between groundwater and cement causes the generation of hyperalkaline solutions (pH 12 – 13...

Shewanella is a genus of marine bacteria capable of dissimilatory iron reduction (DIR). In the context of deep-sea mining activities or submarine mine tailings disposal, dissimilatory iron reducing bacteria may play an important role in biogeochemical reactions concerning iron oxides placed on the sea bed. In this study, batch experiments were perf...

Interaction between Portland cement, rock (siliceous limestone) and acid mine drainage (AMD) from the Iberian Pyrite Belt (IPB) was studied by means of column experiments at laboratory scale. Synthetic acidic solutions (pH = 2) containing sulfate, Fe(II), Al, Mg and minor elements such as divalent cations (Cd, Zn, Cu, Ni and Cd) and an anion As(V)...

Solute diffusion in compacted clays depends on ionic strength through its control on the thickness of the electrical double layer (EDL) on the charged clay surfaces. In the DR-A field experiment (Mont Terri, Switzerland), synthetic porewater was circulated through a borehole for 189 days, leading to the out-diffusion of a variety of tracers into th...

A five years in situ experiment at the Grimsel Test Site (Switzerland) to study water-cement-rock interaction in fractured granite was modelled. It consisted of a hardened cement source in a borehole intersecting a water conducting fracture. Grimsel groundwater was injected into this borehole, and the evolution of water composition was monitored. T...

Transport and retardation parameters of radionuclides, which are needed to perform a safety analysis for a deep geological repository for radioactive waste in a compacted claystone such as Opalinus Clay, must be based on a detailed understanding of the mobility of nuclides at different spatial scales (laboratory, field, geological unit). Thanks to...

We investigated the effect of 0.36% SO 2 in the CO 2 injection stream (added as dissolved H 2 SO 4) on the reactivity of the reservoir (limestone and sandstone) rocks of Hontomin (Spain) at P = pCO 2 = 10 bar and 60°C using flow-through column experiments. Results were modeled with the CrunchFlow reactive transport code. A comparison between the re...

Oxide-type Ni-laterite deposits are characterized by a dominant limonite zone with goethite as the economically most important Ni ore mineral and a thin zone of hydrous Mg silicate-rich saprolite beneath the magnesium discontinuity. Fe, less soluble, is mainly retained forming goethite, while Ni is redeposited at greater depth in a Fe(III) and Ni-r...

To understand the geochemical processes due to rock-cement interaction, an experiment was conducted at the Grimsel underground rock laboratory (Switzerland). Pre-hardened Ordinary Portland Cement was emplaced in a borehole intersecting a water conducting fracture. Grimsel groundwater was circulated and injected into this borehole. Two other borehol...

In this study, we compare the hydrogeochemical response of two fractured reservoir rocks (limestone composed of 100 wt.% calcite and clast-poor sandstone composed of 66 wt.% calcite, 28 wt.% quartz and 6 wt.% microcline) in contact with CO2-rich sulfate solutions. Flow-through percolation experiments were performed using artificially fractured lime...

An in situ experiment at the Grimsel Test Site (Switzerland) to study water-cement-rock interaction in fractured granite was modelled. It consisted of a hardened cement source in a borehole intersecting a water conducting fracture. Grimsel groundwater was injected into this borehole. Two other boreholes at about 0.56 m and 1.12 m from the emplaceme...

Transport and retardation parameters of radionuclides, which are needed to perform a safety analysis for a deep geological repository for radioactive waste in a compacted claystone such as Opalinus Clay, must be based on a detailed understanding of the mobility of nuclides at different spatial scales (laboratory, field, geological unit). Thanks to...

A laboratory-scale tracer test was carried out to characterize the transport properties of concrete from the Radioactive Waste Disposal Facility at El Cabril (Spain). A hyperalkaline solution (K-Ca-OH, pH = 13.2) was injected into a concrete sample under a high entry pressure in order to perform the experiment within a reasonable time span, obtaini...

Laboratory column experiments using crushed marly limestone, bituminous black shale and marl were conducted under different PTotal-pCO2 (atmospheric: 1-10-3.5, subcritical: 10-10 bar and supercritical: 150-37 bar) and T (25 and 60°C) conditions and using different input solutions (gypsum-undersaturated and gypsum-equilibrated). 1D reactive transpor...

The effect of pure and impure carbon dioxide (CO2) on geological storage is uncertain. Oxidation of impurities such as sulfur dioxide (SO2) and hydrogen sulfide (H2S), which may be catalyzed by co-injected oxygen or nitrogen oxides, leads to the formation of sulfuric acid (H2SO4) and a decrease in pH of the formation water. We investigated the effe...

Carbon storage is regarded as a potential technology to reduce CO2 emissions. This study is concerned with CO2 storage in a reservoir rock (limestone) which is a deep saline aquifer containing a NaCl⁻ and sulfate-rich groundwater in equilibrium with calcite and gypsum. The reservoir rock is overlain by a very low permeability formation (marls), whi...

The circulation of CO2-rich solutions through fractured marl cores (caprock) under different flow rates and supercritical CO2 conditions (PTotal = 150 bar, pCO2 = 61 bar and T = 60 °C) led to mineral changes caused mainly by calcite dissolution and to a lesser extent by aluminosilicate dissolution, and by gypsum precipitation adjacent to the fractu...

A laboratory-scale infiltration test was carried out to characterize the transport properties of concrete from the Radioactive Waste Disposal Facility at El Cabril (Spain). A hyperalkaline solution (K-Ca-OH, pH=13.2) was injected into a concrete sample under a high entry pressure in order to perform the experiment within a reasonable time span. The...

Geological CO2 sequestration at pilot-plant scale will be developed at Hontomín (Spain). CO2 will be injected into a limestone reservoir that contains a NaCl- and sulfate-rich groundwater in equilibrium with calcite and gypsum. The caprock site is composed of marl. The present study seeks to evaluate the interaction between the Hontomín marl and CO...

To study the alteration of Portland cement mortar from the El Cabril disposal facility under advective water flow conditions, and to test the applicability of the C-S-H dissolution rate law obtained in our previous study, experiments using columns filled with mortar fragments were performed. Variation of the chemical composition of the output solut...

Injection of CO2 at depth will cause the acidification of groundwater. As a preliminary study for the potential use of MgO as an alternative to Portland cement in injection wells, MgO carbonation has been studied by means of stirred batch experiments under subcritic (pCO2 of 10 and 50bar and T of 25, 70 and 90°C) and supercritic (pCO2 of 74bar and...

A laboratory-scale tracer test has been carried out to improve the characterization of the transport properties of the concrete from the radioactive waste disposal facility at El Cabril (Spain). High entry pressure was employed in order to perform the experiment in a reasonable time span. Lithium, bromide and deuterium were used as tracers. The con...

Two-dimensional reactive transport modeling of the Maqarin Eastern Springs site, a natural analogue for the alteration of a fractured limestone by high-pH Portland cement waters, has been performed using the CrunchFlow code. These 2D calculations included transport by advection-dispersion-diffusion along a single fracture and diffusion in the wall...

Calcite dissolution and gypsum precipitation are expected to occur when injecting CO2 in a limestone reservoir with sulfate-rich resident brine. If the reservoir is fractured, these reactionswill take placemainly in the fractures, which serve as preferential paths for fluid flow. As a consequence, the geometry of the fractures will vary leading to...

Flow-through experiments were conducted to study the calcium–silicate–hydrate (C–S–H) gel dissolution kinetics. During C–S–H gel dissolution the initial aqueous Ca/Si ratio decreases to reach the stoichiometric value of the Ca/Si ratio of a tobermorite-like phase (Ca/Si = 0.83). As the Ca/Si ratio decreases, the solid C–S–H dissolution rate increas...

An in-situ diffusion experiment was performed at the Grimsel Test Site (Switzerland). Several tracers (3H as HTO, 22Na+, 134Cs+, 131I- with stable I- as carrier) were continuously circulated through a packed-off borehole and the decrease in tracer concentrations in the liquid phase was monitored for a period of about two years. Subsequently, the bo...

In situ diffusion experiments are performed in underground research laboratories for understanding and quantifying radionuclide diffusion from underground radioactive waste repositories. The in situ diffusion and retention, DR, experiment was performed at the Mont Terri underground research laboratory, Switzerland, to characterize the diffusion and...

Experiments using columns packed with calcite grains (size 1–2 mm) were carried out to study the behavior of passive treatment systems designed to remediate contaminated water from acid mine drainage (AMD). Two types of synthetic acidic solutions (H2SO4) were injected in the columns: (1) iron-rich with Fe(III) at pH 2, and (2) aluminum-rich at pH 2...

Experiments using columns packed with calcite grains (size 1–2 mm) were carried out to study the behavior of passive treatment systems designed to remediate contaminated water from acid mine drainage (AMD). Two types of synthetic acidic solutions (H2SO4) were injected in the columns: (1) iron-rich with Fe(III) at pH 2, and (2) aluminum-rich at pH 2...

C-S-H gel dissolution kinetics was studied by means of flow-through experiments under CO2-free atmosphere at room temperature (23 ± 2 °C). The starting C-S-H gel was obtained by hydration of commercial C3S (3CaO·SiO2) and consisted of 67 wt% C-S-H with a Ca/Si ratio of 1.7 ± 0.1 and 33 wt% portlandite. Based on the changes in aqueous chemistry and...

A test site for CO2 geological storage is situated in Hontomín (Burgos, northern Spain) with a reservoir rock that is mainly composed of limestone. During and after CO2 injection, the resulting CO2-rich acid brine gives rise to the dissolution of carbonate minerals (calcite and dolomite) and gypsum (or anhydrite at depth) may precipitate since the...

In-situ atomic force microscopy (AFM) experiments were performed to study the overall process of dissolution of common carbonate minerals (calcite and dolomite) and precipitation of gypsum in Na2SO4 and CaSO4 solutions with pH values ranging from 2 to 6 at room temperature (23 ± 1 °C). The dissolution of the carbonate minerals took place at the (10...

In the laboratory, synthetically fractured cores of limestone and sandstone were reacted with CO2-rich brines at flow rates ranging from 0.2 to 60 mL h(-1) and 80 bar pCO(2) and 60 degrees C (supercritical CO2 conditions). Interaction between the sulfate-CO2-rich brines and the primary minerals of the rock caused significant permeability variations...

In the new DR-A in-situ diffusion experiment at Mont Terri, a perturbation (replacement of the initial synthetic porewater in the borehole with a high-salinity solution) has been induced to study the effects on solute transport and retention, and more importantly, to test the predictive capability of reactive transport codes. Reactive transport mod...

Matrix diffusion is a key process for radionuclide retention in crystalline rocks. Within the LTD project (Long-Term Diffusion), an in-situ diffusion experiment in unaltered non-fractured granite was performed at the Grimsel Test Site (www.grimsel.com, Switzerland). The tracers included 3H as HTO, 22Na+, 134Cs+ and 131I- with stable I- as carrier.T...

Hydrated cement and concrete are major components of the engineered barrier system in proposed underground repositories for radioactive waste. Concrete was in contact with a clay-rich rock during 15 years in a borehole at the Tournemire Underground Rock Laboratory in France. Overcoring of the borehole and mineralogical analyses have shown a reducti...

In the DI-A2 experiment several non-reactive and reactive tracers were injected as a pulse in a packed-off borehole in the Opalinus Clay. Unlike the previous DI-A1 test, the design of the Teflon filter in the injection borehole forced the water to flow through the filter and the open space between the filter and the borehole wall (the filter itself...