The development of plastic waste and sewage sludge co-pyrolyzed biochar composites with improved interfacial characteristics for the effective removal of ciprofloxacin

Abstract

The growing global proliferation of plastic waste and sewage sludge (SS) has emerged as a prominent environmental dilemma. This study assessed the efficacy of highly efficient carbon-based adsorbent materials derived from co-pyrolysis of SS and plastic waste in mitigating the concentration of ciprofloxacin (CPX) in an aqueous solution. Each formulated material included varying proportions—20% and 50%—of either polyethylene (PE) or polyethylene terephthalate (PET). Notably, composite with PET—50% exhibited a significant increase in specific surface area to 194.7 m2/g. Efficient adsorption of CPX up to 113.97 mg/g (qms) was reported at pH 5. Pollutant removal was recorded in 12 hours of retention time due to induced π–π interactions, electrostatic and hydrophobic surface interactions highlighting chemosorption. The alkaline pH impacted the adsorption capacity, causing a prominent decline. The SS-PET formulation exhibited a substantial increase in the number of active sites, thereby showing a strong interaction with ionized CPX molecules and yielding superior sorption efficiency by utilizing the novel combination of the material. The regenerative investigations also confirmed the high adsorption for four consistent cycles. Overall, acquiring comprehensive knowledge and practical information from this study will contribute to the effective management of CPX-contaminated wastewater and the mitigation of plastic pollution.