Comparison of conventional pyrolysis and microwave irradiation to transform an amazonic waste into activated carbon for organic contaminants adsorption

Ucuuba (Virola surinamensis) waste was converted into efficient activated carbons, aiming to promote gains and greater sustainability for the riverside cooperatives in Amazonia. The conversion was carried out by conventional pyrolysis (ACP) and microwave irradiation (ACM), and the activated carbons were used to uptake tartrazine yellow (TY) and methylene blue (MB) from water. The results showed that the material produced by the conventional process (ACP) had an SBET of 587.38 m² g⁻¹ and a predominance of micropores combined with mesopores. These features led to higher adsorption capacities (169.32 mg g− 1 for TY and 671.99 mg g− 1 for MB), but lower potential for reuse (3 times). Besides, the conventional process requires more time and reagents. Parallelly, the material developed by microwave (ACM) exhibited an SBET of 88.11 m2 g− 1 and a mesoporous pore-size classification. Consequently, the adsorption capacities were lower (MB = 504.16 and TY = 103.58 mg g− 1). Still, the reuse potential was better (5 times). In addition, ACM requires only 90 s of heat treatment and uses fewer reagents for preparation. It was demonstrated that ACP and ACM from Ucuuba (Virola surinamensis) wastes were developed in different ways, each with its own advantages and drawbacks. However, both materials were efficient and helped sustain the riverside cooperatives in the Brazilian Amazonia.