Zinc and Cadmium Remediation in Contaminated Soil by CaCO₃-Biochar Material from Sugar Beet Industry

Author(s)

Borges, Roger ; Soares, Matheus B. ; Pollo, Mariana P. ; Alleoni, Luis Reynaldo F. ; Giroto, Amanda S. ; Goncalves, Maraisa ; Mueller, Michael ; Jablonowski, Nicolai D. ; Ribeiro, Caue

• Document type: Journal article
• Source: WATER AIR AND SOIL POLLUTION; v. 236, n. 5, p. 17-pg., 2025-05-01.

Abstract

Ore mining and other industrial processes can release toxic elements such as zinc and cadmium into the soil, posing a potential environmental risk. Biochar produced by biomass pyrolysis is proposed to treat contaminated soils by sorption of the contaminants while boosting soil fertility, water retention, and microbial activity. Here, we propose the utilization of Carbokalk, an inexpensive byproduct (spent lime, SL) of the sugar-beet industry, as an ideal source for soil-treatment biochar. We examined the pyrolysis of SL containing up to 20% organic matter at various temperatures and in an oxidizing (air) and inert (N-2) atmosphere. Our results indicate that the pyrolysis temperatures and gas atmospheres greatly influence the physicochemical features of SL-biochar, identifying the most suitable temperature of 600 degrees C for both atmospheres. SL-biochar incubation in contaminated soil has shown the potential to mitigate metal contamination in soils. However, under an oxidizing atmosphere, SL-biochar provides higher reductions in exchangeable Zn and Cd fractions. It accounts for 3% and 20%, respectively, along with increases in fractions associated with carbonate and organic matter. These findings demonstrate the effectiveness of SL-biochar in immobilizing these contaminants. (AU)

• FAPESP's process: 23/09673-0 - Development of wet mechanochemical treatment for the use of WTP sludge as raw material for the production of controlled-release fertilizers
• Grantee: Roger Borges
• Support Opportunities: Scholarships in Brazil - Support Program for Fixating Young Doctors
• FAPESP's process: 22/08032-8 - Nanobiochar modified with thiol in the control of mercury biogeochemistry in the soil in the Amazon region contaminated by mining activity
• Grantee: Matheus Bortolanza Soares
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 20/12210-3 - Development of technological alternatives for the use of ETA sludge as raw material for the production of controlled release fertilizers
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE
• FAPESP's process: 23/01549-8 - Development of wet mechanochemical treatment for the use of WTP sludge as raw material for the production of controlled-release fertilizers
• Grantee: Cauê Ribeiro de Oliveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 23/04271-0 - Impact of temperature variations on chemical and biological attributes of a zinc and cadmium contaminated soil remediated with biochar
• Grantee: Mariana Pezzatte Pollo
• Support Opportunities: Scholarships in Brazil - Master