The Carbonation of Wollastonite: A Model Reaction to Test Natural and Biomimetic Catalysts for Enhanced CO2 Sequestration

One of the most promising strategies for the safe and permanent disposal of anthropogenic CO2 is its conversion into carbonate minerals via the carbonation of calcium and magnesium silicates. However, the mechanism of such a reaction is not well constrained, and its slow kinetics is a handicap for the implementation of silicate mineral carbonation as an effective method for CO2 capture and storage (CCS). Here, we studied the different steps of wollastonite (CaSiO3) carbonation (silicate dissolution -> carbonate precipitation) as a model CCS system for the screening of natural and biomimetic catalysts for this reaction. Tested catalysts included carbonic anhydrase (CA), a natural enzyme that catalyzes the reversible hydration of CO2(aq), and biomimetic metal-organic frameworks (MOFs). Our results show that dissolution is the rate-limiting step for wollastonite carbonation. The overall reaction progresses anisotropically along different [hkl] directions via a pseudomorphic interface-coupled dissolution–precipitation mechanism, leading to partial passivation via secondary surface precipitation of amorphous silica and calcite, which in both cases is anisotropic (i.e., (hkl)-specific). CA accelerates the final carbonate precipitation step but hinders the overall carbonation of wollastonite. Remarkably, one of the tested Zr-based MOFs accelerates the dissolution of the silicate. The use of MOFs for enhanced silicate dissolution alone or in combination with other natural or biomimetic catalysts for accelerated carbonation could represent a potentially effective strategy for enhanced mineral CCS.This research was funded by the Spanish Government (grants CGL2015-70642-R, CGL2015-73103-EXP, CTQ2017-84692-R), EU FEDER funding, the University of Granada (“Unidad Científica de Excelencia” UCE-PP2016-05) and the Junta de Andalucía (grant P11-RNM-7550 and Research Group RNM-179). We thank the personnel of the Centro de Instrumentación Científica (CIC) of the University of Granada for their help during TG-DSC, FESEM, -XRD, and ICP-OES analyses

The role of amorphous P-bearing precursors on barite formation

CRA thanks the SFB 1214 (project A07) funded by the German Research Foundation (DFG) and the Zukunftskolleg from the University of Konstanz. ERA acknowledges funding was provided by the Spanish Government (grant RTI2018-099565- B-I00), the Junta de Andalucía (research group RNM-179), and the University of Granada (Unidad Científica de Excelencia UCE-PP2016-05). In addition, we would like to thank the personnel of the “Centro de Instrumentation Científica” (University of Granada) for their support and help with the electron microscopy analysis.Past climate variations on Earth are recorded in sedimentary rocks by chemical and biological indicators. In this sense, investigations of sedimentary marine barites (BaSO4) have been fundamental to reconstruct geochemical evolution of palaeoenvironments. Despite the significant advances achieved during the past decade, the mechanism of barite formation in the ocean water column in undersaturated conditions and the role of microorganisms remain controversial. Phosphorus-rich, amorphous precursor phases have been suggested to play a key role, although the exact mechanism of marine barite formation from this precursor is not well constrained. In this paper, we evidence that barite can precipitate by replacing amorphous Ba-P precursor phases formed in the absence of living organisms. This occurs by a mineral replacement reaction, yielding an abiotic scenario for barite particles with morphologies, mesostructure and composition resembling barite formed in the marine water column. This demonstrates the need to investigate how this formation process, via the replacement of an amorphous precursor, affects the isotopic and trace element signatures of barite, and how this influences the environmental information obtained from this proxy.SFB 1214 (project A07) German Research Foundation (DFG) Zukunftskolleg from the University of KonstanzSpanish Government (grant RTI2018-099565- B-I00)Junta de Andalucía (research group RNM-179)University of Granada (Unidad Científica de Excelencia UCE-PP2016-05

Virtual environments of teaching learning for training in experimental techniques. Innovation in multidisciplinary groups

In this research, through the development of a teaching innovation project, the aim is to highlight the importance of educational and pedagogical changes that require both the adaptation of teaching to new situations and the possibility of taking advantage of the available resources to be applied in different degrees (master and degree) simultaneously.For this, the innovation experience carried out by a group of professors from the University of Granada who teach subjects in the CiTPA Master, MARA Master and Degree in Conservation and Restoration of Cultural Assets is presented. It addresses the development of unpublished teaching material (videos, manuals for the application of analytical techniques and the use of specialized software, all in a bilingual version), for its integration into different subjects in which it is necessary to make different research techniques known, use of specific software and precise operational activities that are used for the characterization of materials.Competency-based learning through innovation offers students a real and applied experience that has an immediate practical and professional implication, taking advantage of the skills of the new generations. The results, expected in future evaluations, must be analyzed both individually and for the group of subjects, being recognized in advance the good result and the facilities that teamwork, the recognition of skills and the facilities entail in the field of the teacher, the selection of common competences between different subjects and training levels