Biosorption of organic micropollutants onto lignocellulosic-based material

Abstract

The occurrence of organic micropollutants such as pharmaceutical drugs and hormones in the environment reflects the inefficiency of traditional wastewater treatment technologies. Biosorption is a promising alternative from a technical-economic point of view, so understanding the mechanisms of adsorption in new biosorbents is vital for application and process optimization. Within this context, this study aims to evaluate the mechanisms of adsorption and removal of synthetic and natural hormones by Pinus elliottii bark biosorbent (PS) compared to commercial granular activated carbon (GAC) through kinetic models, isotherm models, and thermodynamic models. The adsorbents were also characterized by morphology, chemical composition, functional groups, and point of zero charge. Characterization of the adsorbents highlights the heterogeneous and fibrous morphology and broader range of functional groups found for PS. Kinetic adjustments showed high accuracy for pseudo-second-order, Elovich, and intraparticle diffusion models, presenting multilinearity and evidencing multi-stage adsorption. The isotherms for PS followed high-affinity models, predominantly chemisorption, while those for GAC followed the Langmuir model, where physisorption predominates. These mechanisms were confirmed by thermodynamic models, which also indicated a higher dependence on temperature in the adsorption process. In the fortified water removal test, PS showed removal values higher than GAC, highlighting the advantages of this adsorbent.