Obtención y caracterización fisicoquímica de biocarbones mediante pirólisis de residuos orgánicos del Mercado 25 de junio de Machala.

Abstract

The objective of this research was the production and physicochemical characterization of biochars from organic waste, specifically coconut shell and orange peel, collected from the "25 de Junio" market in Machala. The biochars were obtained through slow pyrolysis at three different temperatures: 300 °C, 400 °C, and 500 °C. Various physicochemical properties were evaluated, including yield, pH, fixed carbon content, ash content, volatile matter content, and surface functional group analysis by Boehm titration (phenolic, lactone, carboxylic, pyrone, and chromene groups). The results showed that increasing the pyrolysis temperature reduced the yield and volatile matter content, while increasing the fixed carbon and ash content. Biochars obtained at lower temperatures (300 °C) exhibited a greater presence of acidic functional groups, such as phenolic and carboxylic groups, which are suitable for the adsorption of metal cations in contaminated water treatment. In contrast, biochars produced at higher temperatures (500 °C) showed a predominance of neutral groups such as pyrone and chromene, which favor the retention of anionic contaminants. Biochars derived from coconut shell showed a higher fixed carbon content and a lower amount of acidic functional groups, suggesting their potential application as a stable adsorbent or catalytic support. On the other hand, orange peel biochars, with a greater diversity of surface groups, stood out for their versatility in the adsorption of different contaminants. These findings demonstrate that the production of biochars from organic waste generated in municipal markets represents a sustainable alternative for organic waste valorization and the development of efficient adsorbent materials for the treatment of contaminated water and/or soil.