Accelerated weathering of limestone
Rising CO2-emissions accompanying the industrial revolution are presumably responsible for climate change and ocean acidification. Several methods have been developed to capture CO2 from effluents and reduce its emission, among those is a promising approach that mimics natural limestone weathering. CO2 in effluent gas streams reacts with calcium carbonate in a limestone suspension.
CO2 (aq) + CaCO3 + H2O ↔ Ca2+ + 2HCO3-
Compared to classical carbon capture and storage methods this accelerated weathering of limestone is cheaper and does not depend on using toxic chemical compounds. Additionally, there is no need for the controversially discussed storage of CO2 underground.
Bicarbonate, as well as calcium, is a component of natural waters and is responsible for buffering the majority of marine and limnic systems. Thus, it is presumed that the bicarbonate- and calcium-rich solution can be released into natural systems without evoking negative impacts. One also could use these waters for neutralization of acidified mining lakes or as a C-source in aquacultures.
In cooperation with the working group Physical Oceanography (Theory) we model chemical and ecological consequences that occur if bicarbonate-rich waters are introduced into the North Sea. Additionally, we analyze the chemical composition of applied and resulting components to ensure that no enrichment of critical substances from the effluent (e.g. nitrogen oxides or trace metals) occurs.