A Comparative Study of Bamboo Biochar and Hydrochar for Pollutant Removal

Biochar and hydrochar produced from the culms (woody stems) of two South American bamboo species were tested for pollutant removal. Guadua angustifolia is a large and locally well-known commercial bamboo species native to Colombia, Ecuador, and Peru, whereas G. weberbaueri is smaller and strictly found in the Amazon region. The thermochemical conversion of their woody fibers was conducted through (a) pyrolysis at 400°C for biochar, and (b) hydrothermal carbonization (HTC) at 240°C for hydrochar production. Both biochar and hydrochar were tested as adsorbent materials to remove methylene blue (MB) dye and heavy metals (lead Pb²⁺, cadmium Cd²⁺, copper Cu²⁺, and chromium Cr²⁺) in aqueous medium. Laboratory results demonstrated that bamboo hydrochar exhibited a significant adsorption capacity for MB, whereas biochar showed better performance in removing heavy metals. A composite material made by combining both adsorbent materials improved the overall pollutant removal efficiency (MB and heavy metals). Characterization studies (e.g., SEM/EDS, XRD, and FTIR) revealed structural and compositional differences between these closely-related bamboo species that affected their adsorption efficiency. These findings demonstrate the potential of bamboo-derived biochar and hydrochar adsorbent materials for wastewater decontamination.