Geochemical potentiality of glauconitic shelf sediments for sequestering atmospheric CO2 of anthropogenic origin

Abstract

ResumenEn este estudio se analizó experimentalmente la velocidad de disolución de la glauconita en función del pH. Los resultados se utilizaron para modelar la evolución geoquímica de sedimentos marinos glauconíticos de la plataforma continental, ante una inyección de CO 2 , y estimar las posibilidades y limitaciones para su fijación en forma de minerales a través de reacciones de carbonatación. Los resultados experimentales muestraron como, en condiciones ácidas, la glauconita es ligeramente más soluble que otros silicatos, dando lugar a productos carbonatados más insolubles. El mecanismo de disolución es incongruente a valores de pH muy ácidos y tiende a ser congruente para valores intermedios y neutros. La superficie reactiva disminuye en el curso del proceso como resultado de la formación de un residuo amorfo. Los datos cinéticos se han empleado para modelar las reacciones de carbonatación en sedimentos marinos mediante cálculos especiación-reacción. En el estudio se evidencia que, para el caso de la glauconita, la eficacia en la fijación de CO 2 depende principalmente de dos factores: la propia cinética de disoluciónespeciación del CO 2 en los sedimentos y la cinética de liberación del Fe 2+ . La mayor limitación del proceso de cara a su implementación, es la evolución del pH hacia valores ácidos. Los resultados sugieren que, a mediano plazo, este proceso podría ser optimizado de forma técnica modificando la respuesta de neutralización de los sedimentos mediante la inyección de agentes alcalinizantes y con una selección adecuada, tanto del modo de inyección como de la composición de los sedimentos y de las zonas diagenéticas más favorables.Palabras clave: disolución de glauconita, baño de flujo continuo, fijación de CO 2 , reacciones de carbonatación, modelos especiación-reacción. AbstractAn experimental analysis was made of the glauconite dissolution rate as a function of pH. The results were used to model the geochemical evolution of glauconitic shelf sediments injected with CO 2 and estimate the possibilities and limitations for sequestering CO 2 in the form of minerals through carbonation reactions. The experimental results show how, under acidic conditions, glauconite is slightly more soluble than other silicates, producing more insoluble carbonated products. The dissolution mechanism is incongruent at very acidic pH values and tends to be congruent at intermediate and neutral values. The reactive surface decreases during the process as a result of the formation of an amorphous residue. Kinetic data were used to model the reactions of carbonation in marine sediments using reaction/speciation calculations. This study shows that, in the case of glauconite, the efficiency of CO 2 sequestration depends primarily on two factors: the dissolution/speciation kinetics of CO 2 in sediments and the kinetics of Fe 2+ release. The greatest limitation for the implementation of this process is that pH evolves to more acidic values. The results suggest that, in the medium term, this process could be technically optimiz...

Chemically Active Silica Aerogel−Wollastonite Composites for CO2 Fixation by Carbonation Reactions

“…The increasing influence of anthropogenic CO 2 emissions on climate change and associated environmental effects are stimulating the search of technologies for CO 2 sequestration as an alternative for emission reduction. The main strategies currently under study involve long-term storage in geological reservoirs, both terrestrial and oceanic, 1 as well as the conversion of CO 2 into solid materials that are more thermodynamically stable. [2][3][4][5] Permanent disposal based on carbonation reactions, a procedure also known as mineral sequestration, 6 is one of the most promising ways currently being studied for CO 2 sequestration.…”

“…Thus, most processes currently under research focus on metal oxide-bearing materials containing divalent cations, usually alkaline-earth metals or ferrous iron. Wollastonite, CaSiO 3 , olivine, Mg 2 SiO 4, and multioxide silicates, such as serpentine Mg 3 Si 2 O 5 (OH) 4 7-9 or glauconite clays 1 incorporating iron and magnesium, are usually employed for this purpose. Silicates containing only alkali metals (such as sodium and potassium) are usually discounted because the corresponding carbonates are very soluble in water.…”

Creep of simulated reservoir sands and coupled chemical‐mechanical effects of CO2 injection

“…In addition, chemically coupled mechanical effects, such as creep due to dissolution reactions, CO 2 -enhanced microcracking, or diffusive mass transfer processes like pressure solution, may lead to time-dependent reservoir compaction. The ultimate extent of any CO 2 mineralization reactions depends on the availability of reactive cations present in phases such as Ca-rich feldspars, Fe/Mg-rich phyllosilicates (clays and micas), and Fe oxides [Aagaard et al, 2004;Carroll and Knauss, 2005;Fernandez-Bastero et al, 2005;Gunter et al, 2000;Palandri et al, 2005;Sass et al, 2002;Wawersik et al, 2001;Xu et al, 2005;Zerai et al, 2006]. By contrast, rates of reaction and of coupled chemical-mechanical creep effects are expected to depend on factors such as pore fluid pH, grain size, temperature, and effective stress [Atkinson, 1979;Chester et al, 2007Chester et al, , 2004Dewers and Hajash, 1995;Hajash et al, 1998;Karner et al, 2003;Niemeijer et al, 2002;Schutjens, 1991].…”

Physical and chemical characteristics of potential seal strata in regions considered for demonstrating geological saline CO2 sequestration

“…The reactions depend on the formation water chemistry, temperature, and pressure ranges (Marini 2007). However, a few experiments with glauconite show that its rate of dissolution, in the presence of either acidic or basic solutions, is faster than a generalized illite and comparable to some carbonates (Fernandez-Bastero et al 2005;Marini 2007). The lack of thermodynamic and kinetic data on the reactions of the common seal mineral phases with injected CO 2 , under reservoir conditions, implies the need for the dissolution rates of these identified minerals to be examined under such conditions.…”