Mechanisms and Kinetics of Saltwater-Driven Carbon Dioxide Capture for Environmental and Ocean Health

点击翻译按钮获取中文摘要

Human-caused excessive carbon dioxide emissions in the ocean and the atmosphere are a significant threat to all life on Earth. This extra carbon dioxide in the ocean leads to an undesirable process called ocean acidification. In addition, the increased carbon dioxide in the atmosphere causes the global temperature to rise, significantly altering the Earth's climate. To mitigate these emissions, many power plants capture carbon dioxide from flue gas through a post-combustion process that separates the carbon dioxide using freshwater and nitrogen-containing chemicals, a promising technology that, unfortunately, relies heavily on freshwater and produces environmentally harmful byproducts. To reduce costs and energy consumption, chemical-free carbon dioxide dissolution in saltwater would be a good alternative to conventional freshwater capture techniques. The overarching objective of this proposal is to evaluate the performance and environmental impact of seawater to capture carbon dioxide using environmentally friendly metal nanoparticle catalysts. Successful completion of the project will provide a strategy to transform the long-term health of atmospheric and ocean environments by removing harmful carbon dioxide using ample natural resources. Beyond the direct impact on the environment, the project will advance decontamination technologies for the agricultural, environmental, and energy industries.A healthy ocean is essential for the global climate, absorbing roughly 40% of carbon dioxide emissions. The development of a novel catalytic carbon dioxide separation approach is critical for addressing rapid global warming and ocean acidification. The goal of this research is to understand the fundamental mechanisms of absorption-based gas separation in natural seawater using polymer-stabilized nickel nanoparticle catalysts. This goal will be accomplished by a comprehensive ex-situ and in-situ examination of the nanoparticle size, morphology, and surface chemistry during reactions in seawater using nanoscale microscopy and spectroscopy. The research will investigate the time-dependent surface chemistry at the interface between the nickel nanoparticle surface and the surrounding solution, enabling a better understanding of the progressive reaction states of the nanoparticles. Fundamental insights into the reaction mechanism of nanoparticle-involved carbon dioxide dissolution in saltwater will explain the unprecedented dissolution efficiency under conventionally unfavorable conditions. To further understand nanoparticle-driven carbon dioxide dissolution in saltwater, the dissolution kinetics will be investigated as a function of carrier fluids, reaction conditions, and catalyst properties. The final tasks will be to evaluate the dominant elements that promote precipitation of carbonate minerals, identify the leading type of minerals, characterize the resultant minerals, and study the feasibility of carbonate-based mitigation for ocean acidification. This research will provide a fundamental understanding of catalytic carbon dioxide separation under variable fluid, reaction, and catalyst property conditions, advancing science towards effective gas separation in the energy and chemical industry. In addition, an understanding of carbonate formation in the heterogeneous saltwater environment will enable the identification of dominant byproducts valuable to marine organisms as well as the impacts of carbonate minerals on marine calcification. The learned knowledge will be transformative by promoting the use of saltwater in many environmental energy processes while saving the increasingly limited freshwater supply.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.