Investigation of carbon distribution with 14C as tracer for carbon dioxide (CO2) sequestration through NH4HCO3 production

This work studies carbon fate using the C-14 tracer technique in ecosystems when synthesized fertilizer is applied. The concept of aqueous ammonia solution scrubbing CO2) from flue gas is used in the fertilizer synthesis. Products after the capture are ammonium bicarbonate (ABC, NH4HCO3) or long-term effect ammonium bicarbonate (LEABC, NH4HCO3 an economic source of nitrogen fertilizer. The ABC or LEABC is used as '' carrier '' to transport CO2 from the atmosphere to the crops and soil. An indoor greenhouse was built, and wheat was chosen as the plant to study in this ecosystem. The investigated ecosystem consists of plant (wheat), soils with three different pH values (alkaline, neutral, and acidic), and three types of underground water (different Ca2+ and Mg2+ concentrations). After biological assimilation and metabolism in wheat receiving ABC or LEABC, it was found that a considerable amount (up to 10%) of the carbon source was absorbed by the wheat with increased biomass production. The majority of the unused carbon source (up to 76%) percolated into the soil as carbonates, Such as environmentally benign calcium carbonate (CaCO3). Generally speaking, alkaline soil has a higher capability to capture and store carbon. For the same soil, there is no apparent difference in carbon capturing capability between ABC and LEABC. These findings answer the question of how carbon is distributed after synthesized ABC or LEABC is applied into the ecosystem. In addition, a separate postexperiment on carbon forms that existed in the soil was made. It was found that up to 88% of the trapped carbon existed in the form of insoluble salts (i.e., CaCO3) in alkaline soils. This indicates that alkaline soil has a greater potential for storing carbon after the use of the synthesized ABC or LEABC from exhausted CO2