Biosorption behavior and mechanism of sulfonamide antibiotics in aqueous solution on extracellular polymeric substances extracted from Klebsiella sp. J1.

The pollution of sulfonamide antibiotics in aqueous system has attracted an increasing attention, however, interactions between the effective biomaterial and sulfonamide antibiotics are not clear. In this study, adsorption capacity and interaction mechanism of EPS from Klebsiella sp. J1 and sulfonamide antibiotics were investigated. The biosorption efficiency of EPS were 70.0%, 55.1%, 51.8%, and 46.7% for SMX, SM1, SM2, and SDZ, respectively. Qualitative and quantitative analysis displayed the almost consistent adsorption mechanism for four sulfonamides on EPS. The adsorption behavior could be described by Langmuir, Freundlich isotherms and the pseudo-second-order kinetics model. Model parameters indicated the chemisorption was the major adsorption type responsible for the adsorption process and demonstrated a good adsorption capacity of EPS for sulfonamides, also confirmed by the SEM observation. Interestingly, 3D-EEM suggested that the driving force was mainly from the hydrophobic interaction of tryptophan and tyrosine during the binding process of EPS and sulfonamides.