This week’s publication highlights cover topics related to direct air capture, forestation and ocean alkalinity enhancement.
Experimental Investigation and Optimization of a Skid-Mounted Direct Air Capture Utilizing Temperature Vacuum Swing
Abstract
Direct air capture (DAC) is a vital technology for achieving net-zero emissions. To assess the performance and optimization potential of traditional temperature vacuum swing adsorption (TVSA)-based systems, a pilot-scale DAC device was established and experimentally evaluated. The results demonstrated an average capture ratio of 44 % and a productivity of 366 kg/y in the TVSA process. Energy analysis revealed that water adsorption and condensation heat contributed significantly to the total energy demand (19 %), while exergy analysis identified the fan and vacuum pump as the main contributors (72.4 % and 16.4 %, respectively). To enhance process efficiency and address challenges in TVSA, a steam-assisted temperature concentration swing adsorption (S-TCSA) was conducted, which reversed the water adsorption pattern during cyclic operation. This modification resulted in a 29 % reduction in heat consumption and an 11 % decrease in electrical consumption. Productivity improved significantly, reaching up to 5.2 kg/m3/kg. Additionally, structural optimization of the adsorber was performed to reduce fan electricity consumption, achieving a pressure drop of 94 Pa and an exceptionally low electrical equivalent consumption of 6.6 GJ/t. Techno-economic analysis revealed a capture cost ranging from $95 to $645 /y, according to different lifetime of adsorbent and plant. Optimal payback period is 0.7 to 1.7 years, highlighting the strong potential for scalable and cost-effective DAC applications.
Wang, K. et al. (2025) Experimental Investigation and Optimization of a Skid-Mounted Direct Air Capture Utilizing Temperature Vacuum Swing 279 (127554) Applied Thermal Engineering.
Read the full paper here: Experimental Investigation and Optimization of a Skid-Mounted Direct Air Capture Utilizing Temperature Vacuum Swing I Applied Thermal Engineering.
Sodium Cation Exchanged Zeolites for Direct Air Capture of CO2
Abstract
Direct air capture technology requires investigating materials that can capture carbon dioxide inexpensively and efficiently, considering their performance under real atmospheric conditions. This study systematically investigated the CO2 adsorption-desorption performance of the representative zeolites (ZSM-5, Beta, Mordenite and Y) in H- and Na-forms using various analytical methods, including in-situ Diffuse Reflectance Infrared Fourier Transform spectroscopy. Compared to the corresponding H-zeolites, the enhancement of CO2 adsorption capacity by Na+ ions was observed for all the structure-type zeolite adsorbents. The Na-ZSM-5 showed excellent performance in the direct air capture of CO2 (DAC) due to its relatively smaller pore size and stronger acid-basic properties. The effective adsorption capacity of Na-ZSM-5 was pronounced at lower Si/Al ratios, making it the most efficient low-concentration CO2 adsorbent. The low silica Na-ZSM-5 exhibited a durable adsorption-desorption capacity after multiple cycles, indicating its practical reusability. When applied to real atmospheric air conditions, this low silica Na-ZSM-5 effectively adsorbed CO2 in the presence of oxygen and moisture, emphasizing its potential for a direct air capture adsorbent. This study provides insights into the properties of zeolites for CO2 capture from air, highlighting their potential as effective DAC sorbents that can be produced on a large scale.
Kim, D. et al. (2025) Sodium Cation Exchanged Zeolites for Direct Air Capture of CO2 25 (100664) Applied Surface Science Advances.
Read the full paper here: Sodium Cation Exchanged Zeolites for Direct Air Capture of CO2 I Applied Surface Science Advances.
Advances in Laser Scanning to Assess Carbon in Forests: From Ground-Based to Space-Based Sensors
Abstract
Purpose of Review
Quantifying the store and flux of carbon across space and time from trees to forest stands, and ultimately at a global scale, has become paramount for a broad range of applications, including individual tree based allometry, landscape scale forest carbon accounting as well as derivation of globally required climate change related variables. Despite this significant information need, the measurement of forest carbon using field methods remains laborious, expensive and logistically complex.
Recent Findings
Laser scanning technologies mounted on terrestrial, unmanned aerial vehicles or drones, aircraft or satellites have revolutionised the estimation of forest carbon at a variety of spatial and temporal scales with each providing detailed and often unique information about the distribution of biomass and carbon within a stand. In this review, we examined the use of laser scanning technologies for this purpose.
Summary
To do so we focus on the recently published (within 10 years) peer reviewed literature and consider studies across four information needs, individual tree, stand, regional / national, and global scales. We consider the type of laser scanning data that is typically acquired, data processing pipelines and the products that are produced. After reviewing these studies, we conclude with a discussion of remaining issues associated with the mapping of forest carbon using laser scanning technologies. We also highlight a number of future research directions to further expand the use of this technology for forest carbon mapping globally.
Coops, N. et al. (2025) Advances in Laser Scanning to Assess Carbon in Forests: From Ground-Based to Space-Based Sensors 11 (11) Current Forestry Reports.
Read the full paper here: Advances in Laser Scanning to Assess Carbon in Forests: From Ground-Based to Space-Based Sensors I Current Forestry Reports.
A Numerical Assessment of Ocean Alkalinity Enhancement Efficiency on a River-Dominated Continental Shelf-A Case Study in the Northern Gulf of Mexico
Abstract
A robust high-resolution coupled hydrodynamic-biogeochemical model was applied to the northern Gulf of Mexico to assess the efficiency of river- and ocean-sourced ocean alkalinity enhancement (OAE). Sensitivity tests indicate that the effectiveness of OAE-induced CO2 uptake is primarily influenced by the amount of alkalinity introduced and local wind-driven mixing, with the former determining the overall uptake and the latter affecting short-term variability. Compared to ocean-sourced OAE (direct ocean release), river-sourced OAE (elevated river alkalinity) is more effective and sustainable. River-sourced OAE has higher CO2 uptake efficiency with reduced spatial and temporal uncertainty and greater overall CO2 uptake. For river-sourced OAE, surface pH increases pronouncedly near the mouths of the Mississippi River. The ideal OAE implementation time includes spring, early summer, fall, and winter. Mid and late-summer implementation is not recommended due to weak mixing, which results in less alkalinity dispersal and greater pH variability. In addition, while the aragonite saturation state generally remains below 6 around the Mississippi River plume, it increases pronouncedly during mid to late summer, risking alkalinity loss due to CaCO3 precipitation and reduced CO2 uptake efficiency near river mouths. Scaling OAE-induced CO2 uptake to the 25 largest rivers in the world indicates that increasing riverine alkalinity concentrations by 10% could remove 23.23 megatons of CO2 annually, meeting 0.37%–0.61% of the 2025–2030 CO2 removal target.
Ou, Y. et al. (2025) A Numerical Assessment of Ocean Alkalinity Enhancement Efficiency on a River-Dominated Continental Shelf-A Case Study in the Northern Gulf of Mexico 20 (024031) Environmental Research Letters.
Read the full paper here: A Numerical Assessment of Ocean Alkalinity Enhancement Efficiency on a River-Dominated Continental Shelf-A Case Study in the Northern Gulf of Mexico I Environmental Research Letters.
Future Scenarios of Global Fisheries and Ocean Alkalinity Enhancement under Socio-Economic and Climate Pathways
Abstract
Achieving global climate goals while ensuring food security in a changing climate presents significant challenges, particularly when relying solely on land-based solutions. Covering over 70% of the Earth’s surface, the ocean remains an underutilized resource for climate mitigation. Ocean alkalinity enhancement (OAE) is one such strategy, designed to strengthen the ocean’s natural carbon sink, reduce atmospheric CO2, and mitigate ocean acidification. However, its implications for fisheries, critical for food security and livelihoods, remain uncertain. This study examines the interplay between global fisheries, OAE, and different future socioeconomic and climatic conditions, using the Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways framework. We explore how global fisheries and OAE could evolve under three combined scenarios: SSP1-2.6 (sustainability-focused), SSP3-7.0 (regional rivalry), and SSP5-8.5 (high fossil fuel dependency). By integrating ecological, economic, societal, and technological perspectives, we develop scenario narratives and quantify key bio-economic parameters, including technological progress, fishing costs, fisheries management, marine aquaculture, and ecosystem carrying capacity. High-emission (SSP5-8.5) and fragmented development (SSP3-7.0) scenarios present significant barriers to the coexistence of OAE and fisheries, whereas sustainability-focused pathways (SSP1-2.6) offer the most favorable conditions for their alignment. Successfully integrating OAE with fisheries management will likely depend on technological advancements, international cooperation, and socio-economic developments. These scenarios are aligned with those used in model-based scenario studies conducted under the frameworks of the Intergovernmental Panel on Climate Change and the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), providing a shared foundation for future work.
Sloterdijk, H. (2025) Future Scenarios of Global Fisheries and Ocean Alkalinity Enhancement under Socio-Economic and Climate Pathways 13 (7) Earth’s Future.
Read the full paper here: Future Scenarios of Global Fisheries and Ocean Alkalinity Enhancement under Socio-Economic and Climate Pathways I Earth’s Future.