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Evaluating feedstocks for carbon dioxide removal by enhanced rock weathering and CO2 mineralization

Carlos Paulo, Ian M.Power, Amanda R.Stubbs, Baolin Wang, Nina Zeyen, Siobhan A.Wilson Abstract Mineralogically complex feedstocks, including kimberlite, serpentinite, and wollastonite skarns, have vast capacities to sequester carbon dioxide (CO2) through enhanced rock weathering and CO2 mineralization. However, only a small reactive fraction of these feedstocks will be accessible for carbon dioxide removal at Earth’s surface conditions. We have developed a new method to evaluate the reactivity of mineral feedstocks that consists of a batch leach test using CO2 coupled with total inorganic carbon (TIC) analysis to quantify easily extractable Mg ...

CO2 sequestration by wollastonite-amended agricultural soils – An Ontario field study

Fatima Haque, Rafael M.Santos, Yi Wai Chiang Abstract Terrestrial enhanced weathering is the spreading of silicate powder on land, and can sequester atmospheric CO2 through carbonation of calcium- and magnesium-rich minerals. When applied to soils, at suitable geochemical conditions, alkaline minerals lead to accumulation of soil inorganic carbon as pedogenic carbonates. Agricultural land covers 37 % of the Earth’s land surface, thus offering a natural sink for atmospheric CO2. Wollastonite (CaSiO3) has been commercialized in Ontario as an agricultural soil amendment for several years, but it is not known if or how much CO2 is sequestered ...

Increasing negative charge and nutrient contents of a highly weathered soil using basalt and rice husk to promote cocoa growth under field conditions

Markus Anda J. Shamshuddin C.I. Fauziah Abstract Technology intervention is a key success to restore properties and productivities of a highly weathered soil (Oxisols). The main challenge is to find materials with the ability to generate soil negative charge, release various nutrients and suppress toxic elements. The objective of this study was to increase negative charge and nutrient content, and suppress Al and Mn toxicities of an Oxisol using finely ground basalt and rice husk compost (RHC) to promote cocoa growth under field conditions. Factorial field experiment of 4 × 4 used finely ground basalt and rice husk compost and arranged in a ...

Carbonate precipitation in artificial soils produced from basaltic quarry fines and composts: An opportunity for passive carbon sequestration

D.A.C. Manning, P. Renforth, E. Lopez-Capel S.Robertson, N. Ghazireh Abstract The proportions of different carbon pools within artificial soils prepared by blending composts with dolerite and basalt quarry fines has changed over a period of 7 years, accumulating inorganic carbon as carbonate minerals newly formed within the soils. With no artificial energy inputs following construction, this is regarded as a passive mineral carbonation process. Carbon isotope data show that up to 40% of the carbon within the soil carbonate is derived from photosynthesis, mixed with carbon from geological sources (limestone present in the quarry fines). Organic ...

Organic acids and high soil CO2 drive intense chemical weathering of Hawaiian basalts: Insights from reactive transport models

Alida Perez-Fodich, Louis A. Derry Abstract We have investigated how biota contributes to rapid chemical weathering of Hawaiian basalts using a reactive transport model and chemical data from a soil chronosequence. These Hawaiian soils have developed under a tropical forest with rainfall >200 cm/yr and exhibit extensive weathering on timescales of 104 years. We developed a series of multicomponent reactive transport models to examine the role of soil respiration and low molecular weight organic acids in generating these intense weathering patterns. The base model starts with a 1-m basaltic porous media reacting with a fluid of rainwater ...

Climate change mitigation: potential benefits and pitfalls of enhanced rock weathering in tropical agriculture

Abstract David P. Edwards, Felix Lim, Rachael H. James, Christopher R. Pearce, Julie Scholes, Robert P. Freckleton and David J. Beerling Restricting future global temperature increase to 2°C or less requires the adoption of negative emissions technologies for carbon capture and storage. We review the potential for deployment of enhanced weathering (EW), via the application of crushed reactive silicate rocks (such as basalt), on over 680 million hectares of tropical agricultural and tree plantations to offset fossil fuel CO2 emissions. Warm tropical climates and productive crops will substantially enhance weathering rates, with potential ...

Temperature dependence of basalt weathering

Gaojun Li, Jens Hartmann, Louis A.Derry, A.Joshua West, Chen-Feng You, Xiaoyong Long, Tao Zhan, Laifeng Li, Gen Li, Wenhong Qiu, Tao Li, Lianwen Liu, Yang Chen, Junfeng Ji, Liang Zhao, Jun Chen Abstract The homeostatic balance of Earth's long-term carbon cycle and the equable state of Earth's climate are maintained by negative feedbacks between the levels of atmospheric CO2 and the chemical weathering rate of silicate rocks. Though clearly demonstrated by well-controlled laboratory dissolution experiments, the temperature dependence of silicate weathering rates, hypothesized to play a central role in these weathering feedbacks, has been diffic...

Carbon Accounting for Enhanced Weathering

Thorben Amann, Jens Hartmann Abstract The inevitable deployment of negative emission technologies requires carbon accounting to incentivise the investment and to foster an active CO2 certificate trading schema. Enhanced Weathering as one of the negative emission technologies is being tested in the field now, but lacks a verifiable and cost-effective carbon accounting approach. Based on results from a lab scale column experiment and field observations, it is hypothesized that the observed stable positive correlation between total alkalinity and electrical conductivity may present a way to easily predict the initial CO2 sequestration at the ...

Enhanced weathering potentials—the role of in situ CO2 and grain size distribution

Thorben Amann, Jens Hartmann, Roland Hellmann, Elisabete Trindade Pedrosa, Aman Malik Abstract The application of rock powder on agricultural land to ameliorate soils and remove carbon dioxide (CO2) from the air by chemical weathering is still subject to many uncertainties. To elucidate the effects of grain size distribution and soil partial pressure of carbon dioxide (pCO2) levels on CO2 uptake rates, two simple column experiments were designed and filled nearly daily with an amount of water that simulates humid tropical conditions, which prevail in areas known for being hotspots of weathering. Multiple materials (dunite, basanite, agricultural ...

Second crop of corn with micaxisto remineralizer in consortium with organic fertilizer

The objective of the present work was to use the mica shale remineralizer in consortium with organic fertilizer for corn culture implanted in the Brazilian Midwest region. The experiment was carried out in the second harvest of the 2020 agricultural year, at Fazenda Panamá, Municipality of Itumbiara, state of Goiás, in the no-tillage system on soybean ridge, implemented by the Center for Study and Research in Plant Science. The location presents as coordinates geographical areas, 17 ° 58 'S latitude and 45 ° 22' W longitude and 554 m altitude. The agronomic characteristics "plant biometrics" evaluated were, the population of plants, performed ...