Adsorptive removal of ciprofloxacin and sulfamethoxazole from aqueous matrices using sawdust and plastic waste-derived biochar: A sustainable fight against antibiotic resistance

We produced carbon-negative biochar from the pyrolysis of sawdust biomass alone (SB) and from the co-pyrolysis of sawdust and plastic waste (SPB). The co-pyrolysis approach in this study was driven by several hypothetical factors, such as increased porosity, surface chemistry, stability, as well as waste management. We applied pyrolyzed and co-pyrolyzed biochars for the removal of ciprofloxacin (CFX) and sulfamethoxazole (SMX). Although SB biochar, due to its more alkaline and amorphous nature, showed better removal efficiencies compared to SPB, the maximum removals of CFX and SMX with SPB were observed as ∼58.8%, and 35% respectively. The primary mechanisms involved in the adsorption process were H-bonding, electrostatic and π–π electron donor-acceptor interactions. Homogenously and heterogeneously driven adsorption of both antibiotics followed the pseudo-second order kinetic model, implying electron sharing/transfer (chemisorption) mediated adsorption. The work is highly pertinent in the context of emerging concerns related to drivers that promote antimicrobial resistance.