Carbon mineralization pathways for carbon capture, storage and utilization

Improvements in the utilization of calcium carbonate in promoting sustainability and environmental health

Calcium carbonate (CaCO3) is an incredibly abundant mineral on Earth, with over 90% of it being found in the lithosphere. To address the CO2 crisis and combat ocean acidification, it is essential to produce more CaCO3 using various synthetic methods. Additionally, this approach can serve as a substitute for energy-intensive processes like cement production. By doing so, we have the potential to not only reverse the damage caused by climate change but also protect biological ecosystems and the overall environment. The key lies in maximizing the utilization of CaCO3 in various human activities, paving the way for a more sustainable future for our planet.

Assessment of Ammoniacal Leaching Agents for Metal Cation Extraction from Construction Wastes in Mineral Carbonation

The use of carbon mineralization to produce carbonates from alkaline industrial wastes is gaining traction as a method to decarbonize the built environment. One of the environmental concerns during this process is the use of acids, which are required to extract Ca2+ or Mg2+ from the alkaline waste to produce carbonates. Conventionally, acids such as hydrochloric, nitric, or sulfuric are used which allow for the highest material recovery but are corrosive and difficult to regenerate as they are utilized in a linear fashion and generate additional process waste. An alternative is to use regenerable protonatable salts of ammonia, such as ammonium chloride (AC) or ammonium sulfate, the former of which is used globally during the Solvay process as a reversible proton shuttle. In this study, we show that regenerable ammonium salts, such as AC (NH4Cl) and ammonium bisulfate (NH4HSO4), can be effectively used for material recovery and the production of calcium carbonate during the leaching of waste cement paste as an alternative to conventional acids such as HCl. Leaching kinetics, postreaction residue, and carbonate characterization were performed to assess the productivity of this system and potential uses of these materials downstream. The stabilization of vaterite was observed in the case of AC leaching, suggesting its importance in the kinetic stability of vaterite and suppression of calcite nucleation. Overall, this study motivates the use of alternative leaching agents, such as salts of ammonia, to facilitate material recovery and carbon capture from alkaline industrial wastes.

Fruit and vegetable waste used as bacterial growth media for the biocementation of two geomaterials

This paper investigates the feasibility of using randomly collected fruit and vegetable (FV) waste as a cheap growing medium of bacteria for biocementation applications. Biocementation has been proposed in the literature as an environmentally-friendly ground improvement method to increase the stability of geomaterials, prevent erosion and encapsulate waste, but currently suffers from the high costs involved, such as bacteria cultivation costs. After analysis of FV waste of varied composition in terms of sugar and protein content, diluted FV waste was used to grow ureolytic (S. pasteurii, and B.licheniformis) and also an autochthonous heterotrophic carbonic anhydase (CA)-producing B.licheniformis strain, whose growth in FV media had not been attempted before. Bacterial growth and enzymatic activity in FV were of appropriate levels, although reduced compared to commercial media. Namely, the CA-producing B.licheniformis had a maximum OD600 of 1.799 and a CA activity of 0.817 U/mL in FV media. For the ureolytic pathway, B. licheniformis reached a maximum OD600 of 0.986 and a maximum urease activity of 0.675 mM urea/min, and S. pasteurii a maximum OD600 = 0.999 and a maximum urease activity of 0.756 mM urea/min. Biocementation of a clay and locomotive ash, a geomaterial specific to UK railway embankments, using precultured bacteria in FV was then proven, based on recorded unconfined compressive strengths of 1-3 MPa and calcite content increases of up to 4.02 and 8.62 % for the clay and ash respectively. Scanning Electron Microscope (SEM) and energy dispersive X-ray spectroscopy (EDS), attested the formation of bioprecipitates with characteristic morphologies and elementary composition of calcite crystals. These findings suggest the potential of employing FV to biocement these problematic geomaterials and are of wider relevance for environmental and geoenvironmental applications involving bioaugmentation. Such applications that require substrates in very large quantities can help tackle the management of the very voluminous fruit and vegetable waste produced worldwide.

Unraveling the rapid CO2 mineralization experiment using the Paraná flood basalts of South America

CO2 capture and storage in geological reservoirs have the potential to significantly mitigate the effects of anthropogenic gas emissions on global climate. Here, we report the results of the first laboratory experiments of CO2 injection in continental flood basalts of South America. The results show that the analyzed basalts have a mineral assemblage, texture and composition that efficiently allows a fast carbonate precipitation that starts 72 h after injection. Based on the availability of calcium, chemical monitoring indicates an estimated CO2 storage of ~ 75%. The carbonate precipitation led to the precipitation of aragonite (75.9%), dolomite (19.6%), and calcite (4.6%).

Tuning Reactive Crystallization Pathways for Integrated CO2 Capture, Conversion, and Storage via Mineralization

ConspectusAchieving carbon neutrality requires realizing scalable advances in energy- and material-efficient pathways to capture, convert, store, and remove anthropogenic CO2 emission in air and flue gas while cogenerating multiple high-value products. To this end, earth-abundant Ca- and Mg-bearing alkaline resources can be harnessed to cogenerate Ca- and Mg-hydroxide, silica, H2, O2, and a leachate bearing high-value metals in an electrochemical approach with the in situ generation of a pH gradient, which is a significant departure from existing pH-swing-based approaches. To accelerate CO2 capture and mineralization, CO2 in dilute sources is captured using solvents to produce CO2-loaded solvents. CO2-loaded solvents are reacted Ca- and Mg-bearing hydroxides to produce Ca- and Mg-carbonates while regenerating the solvents. These carbonates can be used as a temporary or permanent store of CO2 emissions. When carbonates are used as a temporary store of CO2 emissions, electrochemical sorbent regeneration pathways can be harnessed to produce high-purity CO2 while regenerating Ca- and Mg-hydroxide and coproducing H2 and O2. Figure 1 is a schematic representation of this integrated approach.Tuning the molecular-scale and nanoscale interactions underlying these reactive crystallization mechanisms for carbon transformations is crucial for achieving kinetic, chemical, and morphological controls over these pathways. To this end, the feasibility of (i) crystallizing Ca- and Mg-hydroxide during the electrochemical desilication of earth-abundant alkaline industrial residues, (ii) accelerating the conversion of Ca- and Mg-carbonates for temporary or permanent carbon storage by harnessing regenerable solvents, and (iii) regenerating Ca- and Mg-hydroxide while coproducing high-purity CO2, O2, and H2 electrochemically is established.Evidence of the fractionation of heterogeneous slag to coproduce silica, Ca- and Mg-hydroxide, and a leachate bearing metals during electrochemical desilication provides the basis for further tuning the physicochemical parameters to improve the energy and material efficiency of these pathways. To address the slow kinetics of CO2 capture and mineralization starting from ultradilute emissions, reactive capture pathways that harness solvents such as Na-glycinate are shown to be effective. The extents of carbon mineralization of Ca(OH)2 and Mg(OH)2 are 97% and 78% using CO2-loaded Na-glycinate upon reacting for 3 h at 90 °C. During the regeneration of Ca- and Mg-hydroxide and high-purity CO2 from carbonate sources, charge efficiencies of as high as 95% were observed for the dissolution of MgCO3 and CaCO3 while stirring at 100 rpm. Higher yields of Mg(OH)2 are observed compared to that for Ca(OH)2 during sorbent regeneration due to the lower solubility of Mg(OH)2. These findings provide the scientific basis for further tuning these reactive crystallization pathways for closing material and carbon cycles to advance a sustainable climate, energy, and environmental future.

Expanding the Library of Ions for Moisture-Swing Carbon Capture

Developing materials that can more efficiently and cheaply capture carbon dioxide from ambient atmospheric conditions is essential for improving negative emission technologies. This study builds on the promising moisture-swing modality for direct air capture of carbon dioxide by investigating the use of several new anions─orthosilicate, borate, pyrophosphate, tripolyphosphate, and dibasic phosphate─that when introduced into ion-exchange resins allow for the cyclable capture of CO2 under dry conditions and its release under wet conditions. These ions, as well as many others that failed to show moisture-swing performance, are tested and directly compared thermodynamically and kinetically to understand their differences. This includes the use of analytical approaches new to the carbon capture field, such as the correlation of adsorption isotherms to moisture-swing performance, the use of phase lag kinetics, the examination of the humidity-carbon capture hysteresis of the sorbents, and the precise quantification of ion loading using inductively coupled plasma-optical emission spectroscopy. Phosphate dibasic was found to have the largest mass-normalized CO2 moisture-swing capacity, whereas phosphate tribasic had the best performance when factoring in kinetics, and pyrophosphate had the highest swing capacity when normalizing on a per-ion or per-unit-charge basis. This work not only sheds light on ways to improve DAC but also provides insights pertinent to the advancement of gas separation, negative emission technologies, and sorbent materials.

Life cycle assessment of a direct air capture and storage plant in Ireland

Despite the efforts to transition to a low carbon economy, greenhouse gas emissions are surging to critical levels. Carbon dioxide removals (CDR) methods, such as direct air capture (DAC), have been gaining substantial public attention in the last few years. DAC is essential in curbing CO2 concentrations and achieving climate targets. It is said that DAC can be deployed at anywhere, but a throughout life cycle assessment (LCA) is imperative to prove its viability. Therefore, this paper aims to explore the feasibility of constructing a 1 [Formula: see text] plant in Ireland, using Kinsale and Corrib gas fields as storage points. The results showed that the country is an ideal candidate for scaling up this emerging industry. The efficiency is primarily influenced by the construction of the pipeline section, given a reliable sources of heat and electricity. The study highlights the significant impact of distances to the storage points on feasibility, favouring counties near of the gas fields. In conclusion, Ireland has the potential to establish its own DAC industry.

CO2 Mineralization by MgO Nanocubes in Nanometric Water Films

Water films formed by the adhesion and condensation of air moisture on minerals can trigger the formation of secondary minerals of great importance to nature and technology. Magnesium carbonate growth on Mg-bearing minerals is not only of great interest for CO2 capture under enhanced weathering scenarios but is also a prime system for advancing key ideas on mineral formation under nanoconfinement. To help advance ideas on water film-mediated CO2 capture, we tracked the growth of amorphous magnesium carbonate (AMC) on MgO nanocubes exposed to moist CO2 gas. AMC was identified by its characteristic vibrational spectral signature and by its lack of long-range structure by X-ray diffraction. We find that AMC (MgCO3·2.3-2.5H2O) grew in sub-monolayer (ML) to 4 ML thick water films, with formation rates and yields scaling with humidity. AMC growth was however slowed down as AMC nanocoatings blocked water films access to the reactive MgO core. Films could however be partially dissolved by exposure to thicker water films, driving AMC growth for several more hours until nanocoatings blocked the reactions again. These findings shed new light on a potentially important bottleneck for the efficient mineralization of CO2 using MgO-bearing products. Notably, this study shows how variations in the air humidity affect CO2 capture by controlling water film coverages on reactive minerals. This process is also of great interest in the study of mineral growth in nanometrically thick water films.

Goethite Mineral Dissolution to Probe the Chemistry of Radiolytic Water in Liquid-Phase Transmission Electron Microscopy

Liquid-Phase Transmission Electron Microscopy (LP-TEM) enables in situ observations of the dynamic behavior of materials in liquids at high spatial and temporal resolution. During LP-TEM, incident electrons decompose water molecules into highly reactive species. Consequently, the chemistry of the irradiated aqueous solution is strongly altered, impacting the reactions to be observed. However, the short lifetime of these reactive species prevent their direct study. Here, the morphological changes of goethite during its dissolution are used as a marker system to evaluate the influence of radiation on the changes in solution chemistry. At low electron flux density, the morphological changes are equivalent to those observed under bulk acidic conditions, but the rate of dissolution is higher. On the contrary, at higher electron fluxes, the morphological evolution does not correspond to a unique acidic dissolution process. Combined with kinetic simulations of the steady state concentrations of generated reactive species in the aqueous medium, the results provide a unique insight into the redox and acidity interplay during radiation induced chemical changes in LP-TEM. The results not only reveal beam-induced radiation chemistry via a nanoparticle indicator, but also open up new perspectives in the study of the dissolution process in industrial or natural settings.

Continuous and simultaneous conversion of phosphogypsum waste to sodium sulfate and potassium sulfate using quaternary phase diagram

In this present work, the transformation of the Moroccan phosphogypsum (PG) waste, considered a potential source of sulfate, into potassium sulfate compound could help reduce environmental impact and create a new value chain for the phosphate industry. Generally, solid-liquid equilibria are frequently applied in chemical industries. They are a valuable aid in visualizing the precipitation, separation, and purification of a solid phase and the pathways by which crystallization can occur. This process aims to produce potassium sulfate (K₂SO₄), a high-value fertilizer, from sulfate solutions obtained after dissolving PG in a NaOH medium. The quaternary phase diagram Na⁺, K⁺//Cl^-, SO₄^2--H₂O at 25 °C was especially used to determine the operating conditions and the design of a crystallization process during the PG conversion into K₂SO₄. The Jänecke representation of this system enables the determination of the optimal trajectory in the phase diagram for the double decomposition reaction. X-ray fluorescent (XRF) and X-ray diffraction (XRD) techniques were conducted to identify the crystalline phases formed during our process. In summary, the results of this study could contribute to the development of a sustainable valorization PG. Furthermore, K₂SO₄ represents a good alternative to potassium chloride for chloride-sensitive crops.

Enhanced sustainable integration of CO2 utilization and wastewater treatment using microalgae in circular economy concept

Microalgae have been shown to have a promising potential for CO₂ utilization and wastewater treatment which still faces the challenges of high resource and energy requirements. The implementation of the circular economy concept is able to address the issues that limit the application of microalgae-based technologies. In this review, a comprehensive discussion on microalgae-based CO₂ utilization and wastewater treatment was provided, and the integration of this technology with the circular economy concept, for long-term economic and environmental benefits, was described. Furthermore, technological challenges and feasible strategies towards the improvement of microalgae cultivation were discussed. Finally, necessary regulations and effective policies favoring the implementation of microalgae cultivation into the circular economy were proposed. These are discussed to support sustainable development of microalgae-based bioremediation and bioproduction. This work provides new insights into the implementation of the circular economy concept into microalgae-based CO₂ utilization and wastewater treatment to enhance sustainable production.

New technological trajectories to reduce fossil-fuel pollution and support sustainable socioeconomic systems.. [DOI: 10.21203/rs.3.rs-2323975/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

One of the fundamental problems in modern economies is high carbon emissions and diffusion of pollutants from industrial activities focused on fossil-based energy that generate detrimental effects on climate, environment and human population. The goal of this study is to analyze new trajectories of technologies that can reduce, whenever possible, environmental degradation and support a sustainable growth. A model of technological evolution is proposed to detect new technological trajectories directed to sustainability. Results reveal that technologies with a high sustainability perspective for reducing environmental pollution and climate change are: offshore wind turbines, carbon capture storage technology associated with renewable energy, cellular agriculture and blockchain technology directed positive environmental impact. Findings here can sustain decision making of policymakers towards investment in promising technological directions that reduce environmental pollution and sustain ecological transition and sustainable development in human society.

Next steps for solvent-based CO2 capture; integration of capture, conversion, and mineralisation

In this perspective, we detail how solvent-based carbon capture integrated with conversion can be an important element in a net-zero emission economy. Carbon capture and utilization (CCU) is a promising approach for at-scale production of green CO2-derived fuels, chemicals and materials. The challenge is that CO2-derived materials and products have yet to reach market competitiveness because costs are significantly higher than those from conventional means. We present here the key to making CO2-derived products more efficiently and cheaper, integration of solvent-based CO2 capture and conversion. We present the fundamentals and benefits of integration within a changing energy landscape (i.e., CO2 from point source emissions transitioning to CO2 from the atmosphere), and how integration could lead to lower costs and higher efficiency, but more importantly how CO2 altered in solution can offer new reactive pathways to produce products that cannot be made today. We discuss how solvents are the key to integration, and how solvents can adapt to differing needs for capture, conversion and mineralisation in the near, intermediate and long term. We close with a brief outlook of this emerging field of study, and identify critical needs to achieve success, including establishing a green-premium for fuels, chemicals, and materials produced in this manner.

Carbonic anhydrase for CO2 capture, conversion and utilization

Carbonic anhydrase (CA) enzymes, catalyzing the CO₂ hydration at a high turnover number, can be employed in expediting CO₂ capture, conversion and utilization to aid in carbon neutrality. Despite extensive research over the last decade, there remain challenges in CA-related technologies due to poor stability and suboptimal use of CAs. Herein, we discuss recent advances in CA stabilization by protein engineering and enzyme immobilization, and shed light on state-of-the-art of in vitro and in vivo CA-mediated CO₂ conversion for improved production of value-added chemicals using CO₂ as a feedstock.

Biocatalytic Reduction of Formaldehyde to Methanol: Effect of pH on Enzyme Immobilization and Reactive Membrane Performance

Thermodynamic stabled CO2 molecules can be biocatalytically reduced to methanol via three cascade dehydrogenases (formate, formaldehyde and alcohol) with the aid of cofactor as the electron donor. In this study, Alcohol dehydrogenase (EC 1.1.1.1), the third step of the cascade enzymatic reaction which catalyzed formaldehyde (CHOH) to methanol (CH3OH) will be immobilized in an ultrafiltration membrane. The enzyme will be immobilized in the support layer of a poly(ether)sulfone (PES) membrane via a technique called fouling induced enzyme immobilization. The objective of this study is to evaluate the effect of varying pH (acid (pH 5), neutral (pH 7) and alkaline (pH 9)) of the feed solution during immobilization process of ADH in the membrane in terms of permeate flux, observed rejection, enzyme loading and fouling mechanism. The experiment was conducted in a pressure driven, dead-end stirred filtration cell. Reaction conversion and biocatalytic productivity will be also evaluated. The results showed that permeate flux for acid solution were the lowest during immobilization. High concentration polarization and fouling resistance cause lower observed rejection for pH 7 and 9. Enzyme loading for pH 5 give 73.8% loading rate which is the highest compared to 62.4% at pH 7 and 70.1% at pH 9. Meanwhile, the conversion rate during the reaction shows that reaction on fouled membrane showed more than 90% conversion for pH 5 and 7. The fouling model predicted that irreversible fouling occurs during enzyme immobilization at pH 7 with standard blocking mechanism while reversible fouling occurs at pH 5 and 9 with intermediate and complete blocking, respectively. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).