Avaliação do ciclo de vida da produção e aplicação agrícola de nanocarbonato de cálcio obtido da captura de CO₂ de emissões energéticas

Abstract

Extreme climate change, driven by rising global average temperatures and increasing greenhouse gas (GHG) emissions, is largely associated with the continued dependence on fossil fuels, such as mineral coal, which still plays a central role in the energy matrix. In this context, it becomes a priority to develop carbon capture and use (CCU) technologies capable of mitigating part of the emissions associated with these sources without compromising energy security. This study evaluates an innovative route in which CO₂ from industrial emissions is captured by chemical bubbling and converted into nano calcium carbonate (NCC), used as an agricultural nano-liming material. Compared with conventional limestones, NCC presents higher reactivity, better dispersion, and faster neutralization of soil acidity, making it suitable for application in soybean and lettuce production systems. The life cycle assessment (LCA), conducted in openLCA according to ISO 14040:2006 and 14044:2009 and the IPCC 2013 method, initially covered the cradle-to-gate scope. From the cradle-to-field boundary onward, and using the ReCiPe 2016 Midpoint (H) method, the capture of biogenic CO₂ in biomass (soybean and lettuce) and its long-term storage in soil (ΔSOC) were integrated, providing preliminary estimates of up to 12 tCO₂ ha⁻¹ year⁻¹ for soybean and 3 tCO₂ ha⁻¹ year⁻¹ for lettuce, in addition to further gains in the climate balance associated with carbon sequestration and storage in soil. The results indicated that NCC technology can reduce the carbon footprint of agricultural liming, generate carbon credits, and support circular economy strategies in the energy and food production sectors.