Biochar enriched with CaCl¿, CaSO¿, and CaCO¿ for Cd and Zn immobilization and carbon preservation in contaminated soil

• Grant number: 25/13757-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2025
• End date: February 28, 2027
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Luís Reynaldo Ferracciú Alleoni
• Grantee: Isabela Klefenz Rabello de Oliveira
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Soil contamination by heavy metals, such as zinc (Zn) and cadmium (Cd), is a growing concern, especially in mining areas. When in excess, these elements pose risks to human health and the environment due to their toxicity and mobility in the soil. The use of biochar has stood out as a promising strategy for the remediation of such soils, due to its ability to adsorb and immobilize metals.This project will evaluate the potential of biochars produced from urban tree pruning residues doped with calcium salts (CaCl¿, CaSO¿, and CaCO¿) for the retention of Zn²¿ and Cd²¿, the stability of organic matter, and the microbial activity in the soil, aiming for sustainable solutions for the remediation of degraded areas. Doping with these calcium sources aims to increase the cation exchange capacity, raise soil pH, and promote the formation of stable precipitates, such as carbonates and hydroxides.Chemical changes in the soil after the addition of biochars will be evaluated, with a focus on mechanisms such as ion exchange, adsorption, and precipitation, in addition to changes in soil biological communities.