Capture Strategy Research Articles

A Wetting and Capture Strategy Overcoming Electrostatic Repulsion for Electroreduction of Nitrate to Ammonia from Low‐Concentration Sewage (Small 33/2024)

A Wetting and Capture Strategy Overcoming Electrostatic Repulsion for Electroreduction of Nitrate to Ammonia from Low‐Concentration Sewage (Small 33/2024)

Dramatic Improvement of Homogeneous Carbon Dioxide and Bicarbonate Electroreduction Using a Tetracationic Water-Soluble Cobalt Phthalocyanine.

Electrochemical conversion of carbon dioxide (CO2) offers the opportunity to transform a greenhouse gas into valuable starting materials, chemicals, or fuels. Since many CO2 capture strategies employ aqueous alkaline solutions, there is interest in catalyst systems that can act directly on such capture solutions. Herein, we demonstrate new catalyst designs where the electroactive molecules readily mediate the CO2-to-CO conversion in aqueous solutions between pH 4.5 and 10.5. Likewise, the production of CO directly from 2 M KHCO3 solutions (pH 8.2) is possible. The improved molecular architectures are based on cobalt(II) phthalocyanine and contain four cationic trimethylammonium groups that confer water solubility and contribute to the stabilization of activated intermediates via a concentrated positive charge density around the active core. Turnover frequencies larger than 103 s-1 are possible at catalyst concentrations of down to 250 nM in CO2-saturated solutions. The observed rates are substantially larger than the related cobalt phthalocyanine-containing catalysts. Density functional theory calculations support the idea that the excellent catalytic properties are attributed to the ability of the cationic groups to stabilize CO2-bound reduced intermediates in the catalytic cycle. The homogeneous, aqueous CO2 reduction that these molecules perform opens new frontiers for further development of the CoPc platform and sets a greatly improved baseline for CoPc-mediated CO2 upconversion. Ultimately, this discovery uncovers a strategy for the generation of platforms for practical CO2 reduction catalysts in alkaline solutions.

CO2-brine interactions in anhydrite-rich rock: Implications for carbon mineralization and geo-storage

The utilization of subsurface geologic media for carbon capture and storage through mineralization has been recognized as a reliable approach. However, less attention has been given to anhydrite rock type for CO2 mineralization and storage. Anhydrite-rich rock formations, commonly found in various geological settings, have the potential to serve as natural carbon sinks through the mineralization of CO2. Therefore, this study aims to investigate the mechanisms and potential of anhydrite-CO2-brine interactions for carbon storage. The experimental approach involved exposing anhydrite-rich rock to supercritical CO2-brine environments under varying conditions of fluid composition. Mineral transformation of an outcrop anhydrite-rich rock sample in static reactor under subsurface conditions of elevated temperature (60 °C) and pressure (104 bar), in the absence and the presence of SrCl2 was conduct for a one-month period. Mineralogical and geochemical analyses, including, solution analyses, X-ray fluorescence, X-ray diffraction, micro-computed tomography, and mechanical properties were conducted to examine the changes in the composition and rock structure resulting from the interactions. The experimental reactions revealed that anhydrite undergoes mineral transformation upon exposure to supercritical CO2-saturated brine to form stable minerals including calcite, dolomite, magnesite, and strontianite, which contributes to the potential for long-term storage of CO2 in the subsurface geologic media. The efficiency and extent of carbon mineralization were found to be influenced by brine composition. These findings contribute to the understanding of the potential of these formations for carbon storage, opening avenues for further research and the development of effective carbon capture and storage strategies.

Lecture Capture Strategies with Embedded Retrieval Practices: Relationship with Academic Performance

Lecture capture (LC) has been implemented globally to enhance accessible resources supporting academic success. Little is known about the effects of teaching students how to effectively use LC to augment learning. This correlational pilot study used a 14-item Likert-like survey to examine relationships between undergraduate LC viewing practices and final course grade. No statistically significant findings were identified between LC use and course grades. However, the mean course grade was 3.29% higher among students ( n = 32) who implemented and maintained effective LC strategies (M = 90.61, SD = 5.68) compared with those who did not ( n = 18). Six of the 14 LC survey items revealed significant positive correlations and two of the 14 LC survey items revealed significant inverse correlations. These findings could help educators prioritize teaching students how to effectively and efficiently use LC resources to enhance academic outcomes.

Highly efficient capture and conversion of CO2 into cyclic carbonates from actual flue gas under atmospheric pressure

Chemical conversion of CO2 to cyclic carbonates is one of the most attractive strategies for CO2 capture and storage utilization. Herein, a binary organocatalyst of 3-aminobenzylalcohol/n-Bu4NI was used to gently catalyze the insertion of CO2 into the terminal/internal epoxides to generate cyclic carbonates under metal-free and solvent-free conditions. Twelve representative terminal epoxides reacted with CO2 to achieve excellent cyclic carbonate yields of up to 98.3 % at 30 °C and 1 atm CO2 and six low activity internal di-substituted epoxides were converted to corresponding cyclic carbonates with yields of up to 96.2 %. Experiments on actual flue gas and water resistance revealed the potential industrial value of this binary organocatalyst. The yield of cyclic carbonate reached 99 % by using actual flue gas under very mild conditions of 60 °C and 1 atm. The results of 4-fold epoxide amplification experiment showed that the residual CO2 in the flue gas was only 793 ppm after reaction at 1 atm and 60 °C, indicating the good CO2 capture and conversion ability. Reaction kinetics and catalytic mechanism of the cycloaddition were investigated in detail. The synergistic effect among functional groups of catalysts on substrates is the essential factor for the high activity of the catalyst.

Efficient Capture and Low Energy Release of NH3 by Azophenol Decorated Photoresponsive Covalent Organic Frameworks

AbstractIn NH3 capture technologies, the desorption process is usually driven by high temperature and low pressure (such as 150–200 °C under vacuum), which accounts for intensive energy consumption and CO2 emission. Developing light responsive adsorbent is promising in this regard but remains a great challenge. Here, we for the first time designed and synthesized a light responsive azophenol‐containing covalent organic framework (COF), COF‐HNU38, to address this challenge. We found that at 25 °C and 1.0 bar, the cis ‐COF exhibited a NH3 uptake capacity of 7.7 mmol g−1 and a NH3/N2 selectivity of 158. In the adsorbed NH3, about 29.0 % could be removed by vis‐light irradiated cis‐trans isomerization at 25 °C, and the remaining NH3 might be released at 25 °C under vacuum. Almost no decrease in adsorption capacity was observed after eight adsorption‐desorption cycles. As such, an efficient NH3 capture and low energy release strategy was established thanks to the multiple hydrogen bond interactions (which are strong in total but weak in individuals) between NH3 and the smart COF, as well as the increased polarity and number of hydrogen bond sites after the trans‐cis isomerization.

Efficient Capture and Low Energy Release of NH3 by Azophenol Decorated Photoresponsive Covalent Organic Frameworks.

In NH3 capture technologies, the desorption process is usually driven by high temperature and low pressure (such as 150-200 °C under vacuum), which accounts for intensive energy consumption and CO2 emission. Developing light responsive adsorbent is promising in this regard but remains a great challenge. Here, we for the first time designed and synthesized a light responsive azophenol-containing covalent organic framework (COF), COF-HNU38, to address this challenge. We found that at 25 °C and 1.0 bar, the cis -COF exhibited a NH3 uptake capacity of 7.7 mmol g-1 and a NH3/N2 selectivity of 158. In the adsorbed NH3, about 29.0 % could be removed by vis-light irradiated cis-trans isomerization at 25 °C, and the remaining NH3 might be released at 25 °C under vacuum. Almost no decrease in adsorption capacity was observed after eight adsorption-desorption cycles. As such, an efficient NH3 capture and low energy release strategy was established thanks to the multiple hydrogen bond interactions (which are strong in total but weak in individuals) between NH3 and the smart COF, as well as the increased polarity and number of hydrogen bond sites after the trans-cis isomerization.

A Trajectory Planning Method for Capture Operation of Space Robotic Arm Based on Deep Reinforcement Learning

Abstract In order to deal with the complex dynamics and control problems involved in space debris removal, a trajectory planning technique for a spatial robotic arm based on twin delayed DDPG (TD3) in deep reinforcement learning is proposed, and it can accomplish an end-to-end control effect comparable to that of human hand gripping objects. The trajectory planning method for capturing space debris by a floating-base space robotic arm is realized using a space robotic arm task simulation platform built on MuJoCo and using trajectory planners, trajectory trackers, and joint and end-effector control strategies formulated with seven different weighted reward functions. This makes it easier to complete spacecraft in-orbit servicing and maintenance missions. The experiment results demonstrate that the capture strategy can maintain a capture success rate of more than 99%, and debris capture can be mostly finished in three stages when taking the stability of the floating base into consideration by continuously modifying the trajectory.

High-efficiency ultra-thin GaAs solar cells based on ITO/Ag/ITO transparent electrodes and photonic crystals

Ultrathin photovoltaic technology has great potential to improve efficiency and reduce costs. However, achieving optical thickness requires an effective light capture strategy. In this study, for GaAs thin film solar cells with an active layer thickness of 500 nm, we adopt a combination strategy of front-end ITO/Ag/ITO transparent electrodes and back-end photonic crystals (PC). By employing the finite difference time domain (FDTD) simulation, we verify that ITO/Ag/ITO transparent electrodes and AlGaAs PC can effectively enhance the light-harvesting capacity of cells. The proposed cell structure has a spectral absorption rate (SAR) of 0.9781 in the visible wavelength range. To further optimize the photovoltaic performance parameters, we optimize the doping concentration of the pn junction in the cell. Finally, the short circuit current density Jsc, open circuit voltage Voc, fill factor (FF) and photoelectric conversion efficiency (PCE) of GaAs thin film solar cells are successfully increased to 31.10mAcm−2, 1.28V, 88.18% and 35.12%, respectively. This provides crucial experimental validation and theoretical guidance for advancing ultra-thin photovoltaic technology.

A pore-network modeling perspective on the dynamics of residual trapping in geological carbon storage

This study presents the application of an efficient and robust Dynamic Pore-Network Modeling (DPNM) framework for accurate prediction of carbon dioxide (CO2) trapping behavior under the dynamic flow conditions prevalent in subsurface applications. Residual trapping of CO2 is crucial in the context of geological sequestration, serving as a constitutive relationship that controls relative permeability hysteresis and thereby determining the magnitude of CO2 trapping within formations over varying timescales. Utilizing our DPNM framework, we study the complexities of residual trapping in miniature-core-sized digital replicate of a sandstone. We systematically conduct series of two-phase flow simulations to examine the relationships between total residual CO2 amount, trapping efficiency, and initial saturations across a spectrum of capillary numbers and wettability states. Dynamic simulation results lead to a simple power-law scaling equation correlating CO2 trapping efficiency with initial saturation across various capillary numbers. Further analysis explores the morphological and topological characteristics of fluids during primary drainage and various imbibition displacements within the pore network. This work contributes an essential tool and deepens our understanding of CO2 trapping dynamics, driving progress towards more effective and safer strategies for carbon capture and storage.

Impact of electrolyte solutions on carbon dioxide fixation in single chamber Al–CO2 battery

Governments and research & development (R&D) organizations are actively initiating various programs and research strategies for CO2 capture, its utilization, and integration with long duration energy storage from renewable sources worldwide. In line with the carbon capture goals, here we report a novel electrochemical Al-CO2 battery cell, that can simultaneously capture CO2 and convert it into value-added products, in addition to long-duration energy generation and storage. This innovative approach employs cost-effective Al metal as an anode and an in-house synthesized Ni–Fe based bimetallic double hydroxide catalyst as the cathode, with meticulously optimized compositions and morphologies. We explore the impact of different aqueous electrolyte solutions compositions on the cell performance, demonstrating up to 10 h of stable long duration energy storage with a stable voltage profile. The cell exhibits low polarization even at high current densities of up to 12 mA cm−2 and maintains stable cycling over 500 h. Through Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray Diffraction and X-ray photoelectron spectroscopy (XPS) analysis, we determined that the discharge product is either NaAlCO3(OH)2 or KAlCO3(OH)2, distinct from the Al2(CO3)3 typically reported in conventional Al–CO2 batteries.

Access-based cost-benefit analysis

Current methods of cost-benefit analysis (CBA) for transport investments rely on travel-time savings for potential users. This approach presents a consistent and significant historical trend of forecast inaccuracy, and thus has been questioned and criticized. Access, or the ease of reaching valued destinations, can be used as an alternative. Access features a strong correlation with land value which can be measured through hedonic analysis, and subsequently, access gains offered by a transport initiative can be monetised via property uplift. We test this hypothesis and evaluate Sydney's South West Metro Link (SWML).We first develop linear and semi-log ordinary least square hedonic pricing models for house sales in the Sydney region. The models are set up with structural and neighbourhood attributes in addition to access measures, and result in a statistically significant fit.Next, we model changes to job access induced by the SWML. Benefits are then quantified by land value uplift and are estimated at $1.87 Billion in 2031 and between $1.53–$3.08 Billion in 2061, which reflect base and transit-oriented development (TOD) scenarios. The project is thus feasible should certain land use and economic conditions be met, including TOD to occur about station localities by 2061 and if project costs are minimal. Although limitations are noted, access-based CBA exhibits significant promise as an alternative approach to appraisal and has direct application in value capture strategy.

Construction of magnetic covalent organic frameworks based on the monomer-mediated in situ layer-by-layer growth strategy for efficient gold recovery

Creating uniform magnetic covalent organic framework (MCOF) adsorbents for effectively capturing and separating gold presents a considerable challenge. However, achieving this uniformity is crucial for resource recycling and environmental protection. This study introduces a monomer-mediated in situ layer-by-layer growth strategy employing a timed injection method for fabricating magnetic covalent organic frameworks. The hybrid MCOFs produced, Fe3O4@SiO2@COF and Fe3O4@SiO2@COF-DMSA, possess abundant binding sites that enhance adsorption capacities, rapid kinetics, and remarkable regeneration performance for gold recovery. Significantly, the Fe3O4@SiO2@COF exhibits a lower gold adsorption capacity (898 mg g−1), whereas Fe3O4@SiO2@COF-DMSA exhibits an improved Au (III) selectivity and a larger capacity for adsorption (1116 mg g−1). The capturing mechanism of Au (III) by Fe3O4@SiO2@COF-DMSA is predominantly attributed to coordination and reduction, as identified through XPS analysis. This study motivates conceptualizing molecular/ionic capture strategies using core–shell NP/COF hybrid materials to retrieve precious metals.

Integrated CO2 capture and mineralization approach based on KOH and cement-based wastes

To extend current Carbon Capture, Utilization, and Storage (CCUS) strategies and explore a circular carbon economy, an integrated CO2 capture and mineralization approach was developed in this work. KOH was used as CO2 absorption agent to simulate post-combustion carbon capture from flue gas, and then cement-based wastes were used as CO2 mineralization feedstock to convert the sequestered carbonate/bicarbonate ions in the solvent to carbonate minerals and thereby recover and regenerate KOH. The features of the integrated CO2 capture and mineralization process were characterized through ICP-OES analysis, TGA, SEM, quantitative XRD analysis, and particle size analysis. In this study, the carbon capture from the simulated flue gas with CO2 concentration of 10 % using 2.0 M KOH was examined, and the real CO2 capture capacity of 2.0 M KOH was determined at around 1.5 M. After CO2 capture, ground mortar wastes were added into the CO2-loaded KOH solvent, which enables CO2 mineralization and thereby decarbonizes the CO2 liquid absorbent. In CO2 mineralization process, the carbonation characteristics of mortar waste at different pH levels were analysed in-depth. The optimum pH interval for the CO2 mineralization of mortar waste was between 10 and 11, and correspondingly, the highest CO2 sequestration capacity was measured at around 164 g CO2/kg. Apart from CO2 capture and mineral sequestration, another two valuable by-products – silica gels and carbonated mortar waste were also collected and analysed. To increase the applicability of the integrated CO2 capture and mineralization process on a commercial scale, future research was also identified and discussed.

Precise construction of RuPt dual single-atomic sites to optimize oxygen electrocatalytic behaviors for high-performance Zn-air batteries

The development of redox bifunctional electrocatalysts with high performance, low cost, and long lifetimes is essential for achieving clean energy goals. This study proposed an atom capture strategy for anchoring dual single atoms (DSAs) in a zinc–zeolitic imidazolate framework (Zn–ZIF), followed by calcination under an N2 atmosphere to synthesize ruthenium–platinum DSAs supported on a nitrogen-doped carbon substrate (RuPt DSAs-NC). Theoretical calculations showed that the degree of Ru 5dxz − *O 2px orbital hybridization was high when *O was adsorbed at the Ru site, indicating enhanced covalent hybridization of metal sites and oxygen ligands, which benefited the adsorption of intermediate species. The presence of the RuPtN6 active center optimized the absorption–desorption behavior of intermediates, improving the electrocatalytic performance of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). RuPt DSAs-NC exhibited a 0.87 V high half-wave potential and a 268 mV low overpotential at 10 mA cm−2 in an alkaline environment. Furthermore, rechargeable zinc–air batteries (ZABs) achieved a peak power density of 171 mW cm−2. The RuPt DSAs-NC demonstrated long-term cycling for up to 500 h with superior round-trip efficiency. This study provided an effective structural design strategy to construct DSAs active sites for enhanced electrocatalytic performance.

Contrasting light capture strategies between shade-tolerant and -intolerant tree seedlings responding to solar canopy spectral composition

Forest regeneration is a crucial ecological process for promote self-reproduction and restoration, which is essential for maintaining complex community structure and preserving biological resources. Although sunlight have been considered as the main driver of forest regeneration, how light quality shapes functional traits of seedlings is poorly understood in the forest understorey, where spectral compositions of solar radiation change dramatically. We investigated the responses of 15 typical functional traits of Pinus koraiensis and Quercus mongolica to five filter treatments that differed in the spectral transmittance: (a) 95 % of solar radiation was transmitted (280–700 nm); (b) ultraviolet (UV)-B radiation was attenuated (>315 nm); (c) all UV radiation was attenuated (>400 nm); (d) all UV radiation and blue light was attenuated (>500 nm); (e) all UV radiation, blue-green light was attenuated (>580 nm). Our results showed that functional traits responded to UV-B radiation (contrasting treatment [a] vs. [b]) with species-dependence, but consistently showed a positive response to blue light (contrasting treatment [c] vs. [d]). UV-B radiation decreased the relative growth rate (RGR) and leaf area ratio (LAR) of P. koraiensis seedlings by 48 % and 42 %, respectively; however, it increased seedling height, total leaf area (TLA), and above-ground biomass of Q. mongolica. Blue light consistently increased LAR and RGR of two species. Furthermore, Q. mongolica was more plastic in morphological traits (including plant height and TLA) and root/shoot ratio than P. koraiensis to the single spectral region (UV-B, UV-A, blue, and green light), but opposite in physiological and biochemical traits (such as chlorophyll and anthocyanidin). These suggest that two studied species have evolved different light capture strategies in the understorey: Q. mongolica seedlings tended to adjust morphology and biomass allocation to enhance light interception capacity, while P. koraiensis seedlings preferred to adjust physiological and biochemical traits to enhance light utilization efficiency. A better understanding how canopy spectral compositions affect seedling regeneration may provide a new insight for future forest management (i.e. the appropriate gap creation or tree species combination).

Atom-level interaction design between amines and support for achieving efficient and stable CO2 capture

Amine-functionalized adsorbents offer substantial potential for CO2 capture owing to their selectivity and diverse application scenarios. However, their effectiveness is hindered by low efficiency and unstable cyclic performance. Here we introduce an amine-support system designed to achieve efficient and stable CO2 capture. Through atom-level design, each polyethyleneimine (PEI) molecule is precisely impregnated into the cage-like pore of MIL–101(Cr), forming stable composites via strong coordination with unsaturated Cr acid sites within the crystal lattice. The resulting adsorbent demonstrates a low regeneration energy (39.6 kJ/molCO2), excellent cyclic stability (0.18% decay per cycle under dry CO2 regeneration), high CO2 adsorption capacity (4.0 mmol/g), and rapid adsorption kinetics (15 min for saturation at 30 °C). These properties stem from the unique electron-level interaction between the amine and the support, effectively preventing carbamate products’ dehydration. This work presents a feasible and promising cost-effective and sustainable CO2 capture strategy.

Novel approach to CO2 capture: Improving the hybridization between membranes and calcium-looping

A 70 MWe Waste-to-Energy (WtE) plant is modelled to design and evaluate the performance of two CO2 capture strategies: a standalone Calcium-Looping (CaL) process (Case 1) and an innovative hybrid system combining CO2-selective polymeric membranes with CaL (Case 2). The latter involves a CO2 pre-enrichment process facilitated by a pressure gradient within the membrane module, which enhances the CaL performance. The heat released in the CaL process is recovered within a Combined Cycle configuration, taking advantage of the pressurized stream exiting the membrane modules. Comparative analysis reveals that the hybrid system (Case 2) significantly outperforms the standalone CaL process (Case 1) in efficiency and economic viability. With a baseline LCOE for a standard WtE plant without CO2 capture at 150 €/MWh, the LCOE for Cases 1 and 2 are 294 €/MWh and 243.21 €/MWh, respectively. The hybrid system achieves a thermoelectric efficiency of 25.25 %, reducing the energy penalty to 3.32 %points compared to Case 1, which results in 9.49 %points. Furthermore, the cost of avoided carbon emissions is significantly lower in Case 2 (83.82 €/ton CO2) than in Case 1 (155.12 €/ton CO2), underscoring the hybrid system’s superior potential for efficient CO2 capture in WtE applications.

Carbon Dioxide Solubility in Three Bis Tri (Fluromethylsulfonyl) Imide-Based Ionic Liquids.

This study delves into the necessity of mitigating carbon dioxide (CO2) emissions, focusing on effective capture methods to combat global warming by investigating the solubility of CO2 in three ionic liquids (ILs), 1-Decyl-3-MethylimidazoliumBis (Trifluromethylsulfonyl Imide) [IL1], 1-Hexadecyl-3-Methyl imidazoliumBis (Trifluromethylsulfonyl Imide) [IL2] and Triethytetradecyl Ammonium Bis (Trifluromethylsulfonyl Imide) [IL3]. Solubility experiments were conducted at (30, 50 and 70) °C with pressures up to 1.5 MPa. The research shows [IL2] as the superior candidate for CO2 capture, with its longer alkyl chain, and is confirmed by its lower Henry's Law constant. Utilizing the Peng Robinson equation of state, the study correlates well with the solubility measurements using three mixing rules. The study reveals promising results for IL1, IL2 and IL3 surpassing all other published ionic liquids including Selexol/Genesorb 1753, except for 1-Methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide. Insights into the enthalpy and entropy of absorption underscore the significant impact of IL structure on CO2 solubility, emphasizing the potential of tailored ILs for advanced carbon capture strategies. In summary, this research highlights [IL2] as the optimal choice for CO2 capture, offering valuable contributions to the ongoing efforts in combating climate change.

Enhancing carbon sequestration: Innovative models for wettability dynamics in CO2-brine-mineral systems

This study investigates the application of machine learning techniques—specifically convolutional neural networks, multilayer perceptrons and cascaded forward neural networks —to understand the wettability of the CO2/brine/rock system, a critical factor in carbon dioxide (CO2) capture, utilization, and storage in deep saline aquifers. Understanding wettability is essential for improving the efficacy of CO2 storage. The study incorporates variables such as salinity, mineral types, measurement methods, pressure, and temperature into the machine learning models. Using a dataset of 876 samples from existing literature, the proposed models were trained and optimized using the Adam optimizer, Levenberg-Marquardt algorithm, and particle swarm optimization respectively.The performance of these models was evaluated through plot analysis, statistical indicators, and the Taylor diagram, demonstrating a high level of accuracy compared to experimental data. The specifically convolutional neural networks model showed exceptional accuracy in predicting CO2 wettability in brine, with a root mean square error of 0.9612 and coefficient of determination value of 0.9982. The minimal presence of outliers in the specifically convolutional neural networks model further confirms its robustness.This research highlights the effectiveness of deep learning in modeling complex wettability behaviors in CO2-brine-mineral systems, offering substantial insights for enhancing carbon dioxide (CO2) capture, utilization, and storage strategies. The novelty of this work lies in its comprehensive integration of multiple variables and the use of advanced machine learning optimization techniques, going beyond previous efforts by achieving higher predictive accuracy and providing a more detailed understanding of wettability dynamics.