Chemical and biological functionalization of carbons derived from Costa Rican agroforestry production to increase their added value as soil amendment and for the protection of water resources.

Global contamination of natural resources poses a growing threat to human and environmental health, driving the need to develop sustainable, low-cost technologies for decontamination. In this context, biochar has emerged as a promising alternative thanks to its carbon-negative nature, high structural stability, and adsorbent capabilities, characteristics that allow it to retain contaminants in soil, water, and air. This material is obtained through the pyrolysis of residual biomass under limited oxygen conditions, generating a porous, carbon-rich structure that can be modified to optimize its properties.
Modifications to biochar, whether physical, chemical, magnetic, or biological, improve its surface area, porosity, and chemical functionality, increasing its ability to adsorb heavy metals, organic pollutants, nutrients, and greenhouse gases. The main activation strategies include physical activation with water vapor or CO₂, which generates micropores and mesopores; chemical activation using agents such as KOH, H₃PO₄, or H₂SO₄, which introduce oxygenated functional groups; and biological activation, which involves microorganisms or nutrient solutions to increase nutrient retention.
However, non-activated biochar has limitations in the adsorption of negative ions, such as nitrates or phosphates, due to its negative surface charge. Therefore, modification with metals such as iron, copper, or aluminum increases the number of positive charges, improving selectivity and efficiency in the removal of aquatic pollutants. Factors such as pH, temperature, contaminant concentration, contact time, and the presence of interferents also significantly influence the effectiveness of the adsorption process.
The activation of biochar can be carried out in one or two steps: in the first, the activating agent is incorporated during carbonization; in the second, the biochar is activated subsequently, achieving more developed structures and shorter reaction times. In general, chemical activation offers advantages over physical activation by producing a more porous structure and better overall performance.
For all these reasons, research focuses on the production of modified biochar from low-cost local biomass, with the aim of developing efficient materials for contaminant removal and offering viable solutions to communities and entities with limited resources. These initiatives seek to reduce environmental impact and promote accessible and sustainable treatment technologies, applicable not only in Costa Rica but also in other regions of Central America, contributing to a more equitable and ecological management of water resources.

Valorizar biocarbones de baja calidad provenientes de la producción agroforestal costarricense mediante procesos de funcionalización química a baja temperatura y biológica de carbones para generar materiales de alto valor agregado, evaluando su potencial como enmiendas sostenibles en la producción de alimentos y como agentes eficaces para la protección de los recursos hídricos.

Soluciones químicas para el desarrollo