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[Display omitted] • The harvesting efficiency achieved 99.2 % with the application of 60 g/L of FMT@DTAB. • PVDF integrated with extractants demonstrated enhanced butyric acid mass transfer. • Butyric acid showed improved mass transfer coefficient in PVDF with extractants. • PVDF-TDA achieved a 60 % recovery efficiency for butyric acid with 60 g/L of FMT@DTAB. Syngas fermentation utilizing acetogenic bacteria like Clostridium sp. provides a promising method for transforming CO and CO 2 -rich waste gases into valuable products such as short-chain fatty acids (SCFAs) and bio-alcohols, aiding in the reduction of greenhouse gas emissions and supporting carbon neutrality objectives. Magnetic nanoparticle-based coagulants, particularly Fe 3 O 4 @MIL-100(Fe)@TEOS@DTAB (FMT@DTAB), have recently attracted attention due to their efficient recovery and enhanced cell disruption capabilities enabled by cationic surfactant surface modifications. At a dosage of 60 g/L, FMT@DTAB has proven highly effective in achieving significant concentrations of acetic acid (7.06 g/L), butyric acid (6.27 g/L), ethanol (6.43 g/L), and butanol (5.24 g/L), along with notable harvesting efficiency (99.2 %) and intracellular ATP concentration (2.1 mM). Recent research on supported liquid membrane contactors highlights their cost-effective and environment-friendly properties, with an emphasis on minimal extractant usage. This study investigated the behavior of SCFAs using both virgin and supported liquid membrane contactors, focusing on factors such as organic extractant and membrane pore size. PVDF filled with tridodecylamine notably improved butyric acid recovery to around 60 %, with a mass flux of 14.95 ± 0.28 g/m2/h, outperforming virgin and other extractant-filled PVDF membranes. This study enhances resource efficiency and reduces industrial environmental impacts by optimizing the recovery and production of valuable chemicals from waste gases. It supports sustainable and economically viable biotechnology applications, aligning with global climate change mitigation efforts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A two-stage cultivation strategy can increase both biomass and target product yield. • Sequential and multi-component extraction lead to downstream resource efficiency. • Seawater, wastewater, and recycled nutrients are crucial in maintaining efficiency. • Integrative design navigates trade-offs between environmental and economic aspects. • Life Cycle Costing and Sustainability Assessment broaden well-to-wheel analysis. Microalgae hold tremendous potential as sustainable bioresources in carbon capture, climate change mitigation, and the development of net-zero lifestyles. However, scaling up microalgae cultivation necessitates overcoming obstacles in strain selection, bioreactor design, and cultivation strategies. While microalgae were initially viewed as a simple biomass feedstock for energy security, emerging applications such as wastewater bioremediation, carbon capture, and the production of valuable chemicals have reshaped the overall perspective of microalgae. Exciting advancements in microalgal genetic engineering, encompassing evolutionary approach, CRISPR technology, modular cloning toolkits, and bioinformatics, pave the way for optimizing productivity and minimizing environmental footprints. This review delves into crucial aspects of microalgae cultivation, including harvesting, cell disruption, and waste valorization. Additionally, new understandings of integrative design and life-cycle assessment are discussed alongside the promise of bioenergy production, providing the current stage of development and challenges to handle. Ultimately, this review offers new perspectives on microalgal biotechnology aiming to contribute to an eco-friendly green paradigm. [ABSTRACT FROM AUTHOR]

• A review of the spectrum of emerging Direct Air Capture, DAC technologies. • Several categories are under different levels of development with different working principles. • A widespread data on DAC technical, economic, and environmental performance. • Lack of standardized frameworks for DAC assessment. • Multicriterial assessment frameworks can provide comprehensive guidance for rapid deployment. Direct air capture (DAC) is set to play a crucial role in meeting climate change targets as most recent climate scenarios rely on its large-scale implementation. Nevertheless, despite this widespread consensus, DAC performance and impact have not been sufficiently investigated, which has resulted in hindering its wide-scale deployment for climate change mitigation initiatives. Here, we present a comparative review of different DAC technologies and examine their performance from a holistic perspective by considering different aspects, from technical, commercial, and economic to environmental. We classify DAC technologies into five main categories, namely (i) liquid scrubbing, (ii) solid sorbent, (iii) electrochemical, (iv) cryogenic, and (v) membrane, and within each category, various approaches can be employed. We explore key challenges involved in developing each DAC technology and compare their performance using up-to-date data. We then critically analyze the primary factors contributing to the inconsistencies arising from the economic assessment results and provide valuable guidelines for future studies. Overall, the present review can benefit researchers, engineers, and policymakers in obtaining a holistic understanding of these state-of-the-art technologies in addition to filling key gaps in the DAC field. [ABSTRACT FROM AUTHOR]

This paper describes the design and experimental validation of a novel flow-through reactor system conceived for experimental studies to determine the kinetics and thermodynamics of mineral precipitation and dissolution in environmental conditions relevant to CO 2 geological storage. The experimental system was designed to work under a confining pressure of up to 150 bar, temperature up to 150 °C and corrosive conditions. The unique design allows the injection of precise amounts of liquid CO 2 into the reactor while avoiding the formation of multiple CO 2 phases. The modular design enables the in-situ measurement of pH using a pressure resistant in-line probe and electronic gauges which record pressure and temperature at multiple points. The system enables the user to withdraw liquid samples without disturbing the experimental conditions in the reactor. Customized computer software was developed and connected to the system to provide automatic data-logging capabilities, remote process control and the ability to partially shut-down the system in case of safety issues. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phase equilibria of CO 2 + DIOX hydrate for C DIOX between 0.05 mol% and 5.56 mol% • The kinetics of CO 2 + DIOX hydrate is quantified with morphology observation. • Phase separation of DIOX/H 2 O above 3.1 MPa weakens the promotion effect of DIOX. • A comprehensive evaluation of DIOX in the application of hydrate-based CO 2 storage. To reduce anthropogenic CO 2 emissions for the mitigation of climate change require novel CCUS solutions. Hydrate-based CO 2 sequestration (HCS) is a novel carbon-neutrality technology that aims to store CO 2 in solid hydrate form with long-term stability. However, imminent issues exist for the application of HCS in terms of demanding thermodynamic conditions, slow formation kinetics, and low CO 2 gas uptake. These challenges necessitate the quest for an efficient and eco-friendly CO 2 hydrate promoter. In this study, 1,3-dioxolane (DIOX) as a low-toxicity CO 2 hydrate promoter was systematically examined. The phase equilibria, cage occupancy, and the kinetics of binary CO 2 + DIOX hydrate were measured for DIOX concentrations (C DIOX) varying from 0.05 mol% to 5.56 mol%. It was confirmed that DIOX is a dual-function promoter for CO 2 hydrate, but its promotion effect is weakened for C DIOX between 0.60 mol% and 1.00 mol% and for all C DIOX at relatively high pressure. The CO 2 uptake in the hydrate phase increases with C DIOX above 2.00 mol% and is the highest for C DIOX = 5.56 mol% (57.08 ± 6.39 mmol/mol). Based on the morphology observation, hydrate transits from ice-like to slurry to mushy-like and finally to snow-like with increasing C DIOX. Interestingly, we observed that the aqueous phase separates into two phases (i.e., DIOX-rich and H 2 O-rich) at pressure above 3.09 MPa, which explains the gradual loss of the promotion effect. The results of our study provide a comprehensive evaluation on DIOX as a possible promoter for CO 2 hydrate in HCS application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hybrid heating in preparation of activated carbons was investigated. • High CO 2 adsorption was achieved with low KOH impregnation ratio. • Synergic effects observed by using modest microwave intensity and temperature. • Linear correlation between CO 2 uptake and microporosity. • Langmuir model describes the adsorption mechanism in hybrid AC. Microwave has become an attractive technology in the valorisation of renewable biomass and in the mitigation of challenges of climate change. In this work, the synergic effects of coupling microwave and mild conventional heating conditions has been investigated in preparing engineered ultra-micropore carbons from lignocellulosic biomass. The processing conditions were systematically investigated and correlated to the physicochemical properties of activated carbons produced and their performance in post-combustion CO 2 capture. The highest CO 2 uptake (225 mg g−1) was achieved for the hybrid carbon produced at low temperature (600 °C) and modest microwave intensity. The synergic effect of hybrid heating was confirmed by the significant CO 2 uptake increase up to 80 and 60 % for the activated carbons prepared by microwave and conventional heating, respectively. The enhanced adsorption was confirmed by cyclic regeneration up to 99 % after 16 adsorption–desorption cycles, showing a linear correlation between the surface area, micropore volume and CO 2 uptake. The Pseudo-first order model accurately describes the adsorption phenomena, indicating that physisorption is the primary mechanism governing the process. The results acquired from this study highlight the process intensification in the synthesis of porous materials with comparable properties that are typically attained in conventional heating using energy intensive conditions. Additionally, this approach reveals the benefits of conventional treatment for increasing the material's microwave susceptibility and as consequence to reduce the processing time by microwave heating. The synergic effects confirms the potential of hybrid heating for applications where fast and selective heating is paramount. [ABSTRACT FROM AUTHOR]

[Display omitted] Mitigation of climate change by reducing the anthropogenic CO 2 emissions has recently gained huge momentum. A prime pathway to achieve it in the short-medium term lies within capturing CO 2 from industries' flue gases. Post-combustion CO 2 capture (PCC) is the most mature methodology for large-scale CO 2 capture and closest to market. However, the conventional chemical absorption-based PCC process implies high regeneration energy requirements, constituting the majority of the energy load when adding PCC to the plant from which the CO 2 is going to be captured. As such, reducing the overall parasitic load of the conventional process is of interest. Changing the solvent or improving the process flowsheet are two main methodologies to achieve higher energetic efficiency and lower exergy losses. As there are several reviews dealing with novel solvents, this review critically evaluates the progress in improving the conventional PCC process through modifications of process configurations and shadowed by solvent replacements as drop-in solutions. The process configurations were grouped into absorption and stripping enhancement categories. A comparative analysis was conducted between the different available schemes in the literature and interactions between solvents and process configurations were showcased, highlighting the advantages and shortcomings of some of them. The review reveals the need for standardized framework and optimization algorithms using exergo-economic performance indicators for integrated solvent and process synthesis. [ABSTRACT FROM AUTHOR]

• Full integration of TEA/LCA was applied for MCCKD within a conventional cement plant. • Scenarios were evaluated as the basis of a cement world of net-zero CO 2 emissions. • Implementing MCCKD in a cement plant presents benefits in direct CO 2 reductions. Climate change mitigation entails reaching net-zero emissions, which in turn requires unprecedented actions in all aspects of society. These include the cement industry, which represents 7% of global CO 2 emissions. A proposed option for reducing CO 2 emissions in the cement industry is the use of CO 2 -containing flue gas and cement kiln dust (CKD) for producing mineral carbonates that serve as non-reactive fillers for blending cement. This work proposes the mineral carbonation of CKD (MCCKD process) to convert CO 2 to synthetic carbonates and analyzes under which conditions the MCCKD process can be a promising concept for the cement industry in Colombia. For this purpose, an existing conventional cement plant (base case) is compared with a hypothetical cement plant with MCCKD. Both systems are compared in an integrated techno-economic and environmental assessment and in eight emission scenarios with no full-abatement (NA) and full-abatement (FA) parameters, assuming a conventional energy mix and a renewable energy mix. Key findings show that implementing the MCCKD process increases by 27–30 % the cost of goods manufactured (COGM) for a 7–8% reduction in CO 2 -emissions for fossil and renewable scenarios, respectively, in the NA scenario. In contrast, the FA scenarios result in a reduction of COGM by 13–14 % for fossil and renewable scenarios. The evaluation supports the economic feasibility of implementing the MCCKD within a conventional cement plant from a net-zero emissions perspective, with total CO 2 -captured costs ranging from 37.2 to 43.9 USD/t CO 2-captured (FA). The analysis shows that the MCCKD process, combined with transport and storage with renewable energy sources, has significant economic and environmental advantages compared to the same process based on fossil energy sources. [ABSTRACT FROM AUTHOR]

• Different silicate minerals showed highly different carbonation behaviours. • Olivine dissolution was the rate controlling step during natural silicate carbonation. • Carbonation capacity of natural silicates should be corrected for application. • Kinetics of natural silicates carbonation should be based on corrected capacity. • Carbonating mixtures of various silicates is more realistic for potential scale-up. Carbon sequestration by mineral carbonation of basic silicate minerals is an important technique for climate change mitigation, because of the formation of stable mineral carbonate products and the abundant resources of amenable minerals in nature. In practice, direct aqueous mineral carbonation may need to treat natural multiple-mineral mixtures including partially serpentinized ultramafic silicates, as potentially combined with mineral processing operations and enhanced metal recovery. This work investigated the kinetics of direct mineral carbonation of multiple-minerals natural silicate samples under conditions of 34.5 bar CO 2 partial pressure, 175 ℃ and concentration of 1.5 m NaHCO 3 , with corresponding carbonation efficiency more than 85% in 3 h. It was found that the carbonation of a natural mixture of minerals was kinetically controlled by chemical reaction of the olivine dissolution under moderate CO 2 partial pressure and aqueous ionic strength, regardless of olivine content and associated mineral compositions. It was important for kinetics analysis to calculate the effective mineral carbonation capacity based on the magnesium and iron contents in olivine. If the carbonation capacity was calculated based on the total content of magnesium, calcium and iron as is conventional, the mineral carbonation efficiency was proportional to the olivine content in natural silicate samples. The carbonation process of the natural mixtures could be completely attributed to the reaction of olivine while the other silicate minerals including serpentine and diopside, as well as iron sulfides and magnetite, did not significantly participate. [ABSTRACT FROM AUTHOR]