Converting woody biomass ash and CO2 into valuable resources via a sustainable chelation approach

Abstract

Efficient valorization of woody biomass ash is essential for advancing sustainable bioenergy systems and supporting a low-carbon circular economy. A key challenge lies in safely managing heavy metals while recovering valuable resources. In this study, we developed a sustainable process for simultaneously producing high-purity potassium fertilizer (KHCO₃) and industrial raw material (CaCO₃) from woody biomass ash. This is achieved using a recyclable CO₂-enriched solution containing a green chelating agent N,N-bis(carboxymethyl)-L-glutamic acid (GLDA), which enhances extraction and selective precipitation of metal ions under mild conditions (<100°C, ambient pressure). The process enables effective CO₂ capture and storage, significantly reducing heavy metal Cd, Cu, As, Pb, Zn content in the ash and recovers valuable K and Ca resources. By integrating carbon mitigation with material recycling, this approach provides a practical and scalable pathway toward circular economy implementation in biomass-based power generation.