Zinc chloride-assisted activation of açaí biomass for herbicide removal: Insights from adsorption and molecular modeling

In addressing the environmental impact of açaí pulp production waste, this study explores the sustainable transformation of Euterpe oleracea fruit pits into activated carbon using a zinc chloride (ZnCl2) activation process. The primary aim is to repurpose this agricultural by-product for the efficient removal of atrazine (ATZ) and 2,4-dichlorophenoxyacetic acid (2,4-D) herbicides from contaminated water. The produced activated carbon demonstrated superior adsorptive properties, with a specific surface area (SBET) of 920.5 m2g-1, substantial pore volume (Vp) of 0.467 cm3g-1, and an average pore diameter (Dp) of 1.126 nm, showcasing its potential as an effective adsorbent. Experimental adsorption tests revealed that this carbonized material could remove up to 95% of ATZ and 89% of 2,4-D under optimized conditions. Advanced techniques, including Density Functional Theory (DFT) simulations and COSMO-RS analysis, provided profound insights into the adsorption mechanisms, particularly emphasizing the crucial role of hydrogen bonding interactions. Identified as key mediators, hydrogen bonding-induced contact energy facilitated herbicide adsorption, corroborated by Electron Localization Function (ELF) analysis. These findings not only suggest a viable method for mitigating the environmental issue posed by açaí pulp waste but also contribute to the development of eco-friendly adsorbents for water purification. The research underscores the potential of using biomass waste for environmental remediation, aligning with global sustainability objectives.