This week’s publication highlights relate to direct air capture, marine CDR and enhanced rock weathering.
Recent Advances in Sorbent Materials for Direct Air Capture of CO2
Abstract
Direct air capture (DAC) has emerged as a scalable strategy for atmospheric CO2 removal, with material innovations being central to its advancement. This review explores recent developments in DAC materials, including solid sorbents and liquid solutions, with a focus on their design, performance, and scalability. Key properties such as CO2 sorption capacity, kinetics, and stability under diverse conditions are critically analyzed. Emerging materials, including metal-organic frameworks (MOFs), amine-functionalized adsorbents, and advanced polymeric materials, are examined for their potential to enhance efficiency and reduce energy consumption. Challenges related to material synthesis, regeneration, and long-term durability are discussed alongside strategies for integrating these materials into scalable DAC systems. While previous reviews have addressed DAC scrubbers, a systematic yet comprehensive classification was lacking. This review fills that gap by categorizing DAC materials into a structured quadrant and compiling both foundational studies and recent advancements into detailed tables, providing a clear and organized overview of the field’s progression. By synthesizing breakthroughs and identifying future directions, this review underscores the need for innovative materials to drive down costs, improve performance, and facilitate large-scale deployment of DAC in climate mitigation efforts.
Maity, K. and Goswami, D. (2026) Recent Advances in Sorbent Materials for Direct Air Capture of CO2 114 (101263) Progress in Energy and Combustion Science.
Read the full paper here: Recent Advances in Sorbent Materials for Direct Air Capture of CO2 I Progress in Energy and Combustion Science
Seaweed Aquaculture and Waste Stream Integration for Blue Carbon: A Systematic Review of Carbon Pathways and Mitigation Strategies
Abstract
Seaweed aquaculture integrated with waste streams is a promising blue-carbon pathway. This review goes beyond narrative synthesis by introducing three contributions: (i) a cross-system taxonomy of integration modalities, (ii) a concise measurement, reporting, and verification (MRV) protocol accompanied by a practitioner checklist, and (iii) a Crediting Readiness Scorecard (CRS) that operationalizes additionality, durability, leakage, and governability. We systematically reviewed studies published between 2016 and 2025 on coupling seaweed cultivation with aquaculture effluents, municipal wastewater, and flue-gas CO₂, following PRISMA screening and a simple risk-of-bias appraisal; where data permitted, we performed a small quantitative synthesis for nutrient removal and carbon-capture indicators. Our aim is to evaluate operational conditions, carbon pathways (harvest, particulate organic carbon export, dissolved and recalcitrant dissolved organic carbon), and MRV feasibility, while proposing an implementable protocol and scoring tool that standardize assessment across sites and species. Findings indicate that integration generally elevates productivity and carbon capture, but outcomes hinge on nutrient management, residence time and flow distribution, thermal control, and pretreatment addressing pathogens, metals, and co-pollutants. Using the CRS, aquaculture-effluent integrations emerge as nearer-term candidates for conservative crediting; municipal-wastewater and flue-gas routes can approach comparable readiness with stronger pretreatment, clearer system boundaries, and leakage safeguards. MRV remains challenged by air–sea flux attribution, spatial heterogeneity, and inconsistent standards; we map fit-for-purpose metrics net ecosystem exchange/eddy covariance, pCO₂ sensors, ¹³C tracers, and traps/cores to farm, bay, and shelf boundaries with QA/QC routines to constrain uncertainty. Technology assessments highlight artificial upwelling, CO₂ dosing, longline offshore arrays, and automated sensing as promising yet constrained by energy demand, reliability, and permitting; we synthesize indicative readiness ranges to guide deployment. Overall, the review converts disparate findings into actionable guidance through the taxonomy, MRV protocol, and CRS, and sets priorities for MRV optimization, standardized LCA distinctions between avoided emissions and removals, and scaling strategies suited to data-limited tropical contexts.
Mulyani, S. (2026) Seaweed Aquaculture and Waste Stream Integration for Blue Carbon: A Systematic Review of Carbon Pathways and Mitigation Strategies 7 (1) Journal of Environmental and Agricultural Studies.
Read the full paper here: Seaweed Aquaculture and Waste Stream Integration for Blue Carbon: A Systematic Review of Carbon Pathways and Mitigation Strategies I Journal of Environmental and Agricultural Studies.
The Potential of Enhanced Rock Weathering for CO2 Removal and Soil Organic Carbon Storage via Organo-Mineral Aggregation: The Trade-Off Induced by Basaltic Rock Particle Size
Abstract
Carbon dioxide removal (CDR) via enhanced rock weathering (ERW) strongly depends on rock particle size. While ERW models typically link finer particle size to greater CDR, their tendency to aggregate with soil components such as organic matter (OM) may impede weathering. The inconsistent effects of ERW on soil OM storage in recent studies reinforce the need to clarify underlying mechanisms. We thus tested if finer basaltic rock promotes organo-mineral association while lowering CDR through incubation experiments (rock alone and rock-plant residue-sand mixture) under water regimes with or without weekly leaching. After six months, we analyzed total carbon, extractable metal(loid)s, organo-mineral aggregate formation (by density fractionation), and inorganic carbon contents (by XANES and leachates). Coarse basaltic rock (106–150 μm) showed faster abiotic and biologically induced weathering. Contrarily, fine basaltic rock (20–38 μm) led to greater organo-mineral aggregation and OM accrual, which was attributable to higher particle numbers, geometric surface area, and binding agents (inherent and increased reactive metal(loid)s). The amount of organic carbon stabilized in meso-density aggregates by basaltic rock was one order of magnitude higher than the estimated CDR, regardless of the water regimes. These results exhibit the first direct evidence that rock particle size could induce the trade-off between CO2 removal and OM stabilization, which implies that the current ERW models may severely overestimate CDR potential due to basaltic rock interaction with OM and its weathering products. Further research into rock interactions with soil components is essential for improving model prediction and optimizing ERW applications.
Yang, P. et al. (2026) The Potential of Enhanced Rock Weathering for CO2 Removal and Soil Organic Carbon Storage via Organo-Mineral Aggregation: The Trade-Off Induced by Basaltic Rock Particle Size 9 (169) Biogeochemistry.
Read the full paper here: The Potential of Enhanced Rock Weathering for CO2 Removal and Soil Organic Carbon Storage via Organo-Mineral Aggregation: The Trade-Off Induced by Basaltic Rock Particle Size I Biogeochemistry.
Influence of Enhanced Rock Weathering of Nepheline-Syenite Tailings on Major and Trace Elements Accumulation in Wheat
Abstract
Soil nutrient depletion and quality are critical challenges facing agriculture and have been exacerbated by the long-term use of chemical fertilisers. A 14-week pot experiment was conducted, with nepheline-syenite tailings (NST) serving as the sole non-nitrogen nutrient source for wheat, to determine the potential of NST to improve the soil nutrient status. The impact of NST on plant health was examined at five application rates (0, 1.25, 5, 10, and 20 g/kg of artificial soil). At the end of the experiments the pH, major and trace elements (e.g., Ca, Mg, P, S, K, Fe, Mn, Zn, Si, Cu, Mo) in both the rhizosheath and the bulk soil, and wheat biomass (both above and belowground) were measured, and used to calculate nutrient uptake. These parameters generally increased with higher NST application rates. Wheat biomass increased with increasing NST doses up to 10 g/kg of artificial soil. Potentially toxic elements (PTEs) such as Al, As, Sr, Rb, and Ba increased in the soil; however, their concentrations remained 52.5% to 91.7% below the world soil average, suggesting minimal environmental risk. The P and K nutrient use efficiency (NUE) decreased with increasing application, indicating that NUE may not be effective for evaluating slow-releasing amendments where the elemental totals do not represent the bioavailable fraction. The findings improve our understanding of how NST can be used to enhance soil fertility and agricultural yield, providing valuable insights for its effective use as soil amendments, particularly in regions with readily available silicate rocks of this type and nutrient-depleted soils.
Apori, S. et al. (2026) Influence of Enhanced Rock Weathering of Nepheline-Syenite Tailings on Major and Trace Elements Accumulation in Wheat 77 (1) European Journal of Soil Science.
Read the full paper here: Influence of Enhanced Rock Weathering of Nepheline-Syenite Tailings on Major and Trace Elements Accumulation in Wheat I European Journal of Soil Science.
Direct Air Capture (DAC) and CO2 Sequestration with Waste Brine Using a Novel Sorbent at Ambient Temperature
Abstract
There is a global consensus that CO2 capture and sequestration should continue at an accelerated pace to meet the IPCC (Intergovernmental Panel on Climate Change) recommendation in lowering the CO2 concentration in the atmosphere. In recent years, deployment of direct air capture (DAC) has been on the rise through use of solid sorbents. In this study, we present for the first time a new DAC process that eliminates the need for geological storage and thermal desorption. A hybrid polymeric ion exchanger for decarbonization (DeCarbon-HIX), that is robust and durable, forms the heart of the process. Besides high CO2 capture capacity from the atmosphere, the DeCarbon-HIX sorbent is amenable to regeneration with waste brine solution (e.g., produced water) containing Ca2+ whereby CO2 is mineralized as solid, innocuous CaCO3(s). Note that other recently developed DAC processes, namely, moisture swing DAC and electrochemistry-driven processes, operate without thermal energy but require CO2 storage. This new avenue for DAC offers great opportunities to capture CO2 in countries and islands where reliable geological storage is non-existent. This carbon dioxide removal methodology can be rapidly scaled up in many regions that are currently inaccessible to DAC.
Wu, X. (2026) Direct Air Capture (DAC) and CO2 Sequestration with Waste Brine Using a Novel Sorbent at Ambient Temperature 100584 Carbon Capture Science & Technology.
Read the full paper here: Direct Air Capture (DAC) and CO2 Sequestration with Waste Brine Using a Novel Sorbent at Ambient Temperature I Carbon Capture Science & Technology.