Effect of Hydrodynamic Condition on Adsorption of Sulfadiazine on Marine Sediments

Abstract

In the present study, the adsorption behavior of sulfadiazine (SDZ) on various sediments under different hydrodynamic conditions generated by a rocking shaker was investigated. Based on the dye mixing experiments, three regimes with different hydrodynamic characteristics, i.e., laminar, transition, and turbulent regimes, were identified. The hydrodynamic intensity was found to have a positive effect on the adsorption of SDZ, In general, the adsorption capacity followed the order of turbulent > transition > laminar > static. Compared to quartz sands, montmorillonite exhibited a narrower range of adsorption capacity under different hydrodynamic conditions, which implies it is less sensitive to the hydrodynamic conditions. For adsorption kinetics, sands fit the pseudo-first-order model, while montmorillonite fits the pseudo-second-order model. For adsorption thermodynamics, the Freundlich model showed a better correlation coefficient for all sediments. In addition, it was found that particle size could affect the antibiotic adsorption capacity, and the presence of salts inhibited the adsorption performance.