Modeling aqueous contaminant removal due to combined hydrolysis and adsorption: oxytetracycline in the presence of biomass-based activated carbons

ABSTRACT

This work demonstrates a new model to determine which mechanism(s) – adsorption or hydrolysis – is (are) responsible for the removal of oxytetracycline (OTC) from water in the presence of biomass-based activated carbons (ACs). OTC removal using potassium hydroxide-activated biochars follows pseudo-second-order kinetics, initially dominated by chemisorption. Overtime, hydrolysis increasingly dominates. Conversely, most CO₂-ACs display weaker chemisorption, with hydrolysis dominating OTC disappearance. Chars prepared using higher temperature CO₂ activation show that both hydrolysis and weak chemisorption are important in OTC removal. A computational model describes these concurrent pseudo-first- and second-order processes, rather than oft-employed sequential models.

KEYWORDS:

• Adsorption
• hydrolysis
• oxytetracycline
• water treatment
• activated biochar

Acknowledgments

J. Ford acknowledges The University of New Hampshire McNair Scholars Program for funding this investigation. J. Goldfarb acknowledges support from the Boston University Initiative on Cities.

Supplementary material

Supplemental data can be accessed here.