Prospective life cycle assessment of activated carbon production derived from banana peel for methylene blue dye removal

Abstract

Activated carbon (AC) produced from agro-industrial waste is an interesting adsorbent in water purification and effluent treatment processes. In this work, activated biochar (BFAC) from banana peel waste (BPF) was prepared by chemical activation (NaOH) followed by pyrolysis at 600 °C to remove methylene blue (MB) from wastewater. BFAC was characterized by TGA, XRD, SEM, and FTIR techniques. The influence of dye concentration (10, 25, 50, 100, 250, and 500 mg L−1) and zero point charge (ZPC) were investigated. Besides, a Life Cycle Assessment (LCA) was conducted to evaluate and analyze the environmental effects of the developed process. BFAC presented a well-developed pore structure with a predominance of mesopores and macropores, influencing the MB removal capacity. The highest efficiency for dye removal was 62 % after 10 min to an initial concentration of 50 mg.L-1. Temkin, Langmuir, and Freundlich, isotherm models defined the adsorption isotherms well. The Langmuir model represented the best fit of experimental data for BFAC with a maximum adsorption capacity of 417 mg g−1. Regarding LCA, a prospective approach at the early stage of development was conducted to orient the transition from laboratory to industrial scale, aiming at providing a competitive CO2-based technological route. The proposed scenarios suggest that this route is promising either from the life cycle assessment or the circular economy perspective. Thus, BFAC can be considered as an adsorbent of great practical application for post-treatment of wastewater effluents aiming to remove contaminants.