Efficient adsorption of tetracycline in aquatic system by thermally-treated sediment

The disposal of dredged sediment is a considerable challenge for environmental protection and resource utilization. In this study, the dredged sediment was thermally-treated to prepare as adsorbent and utilized for tetracycline adsorption. Sediments based adsorbents under different pyrolysis temperature and atmosphere (N₂ and limited oxygen) were obtained and 600 °C and N₂ atmosphere (600AN) exhibited maximum TC adsorption capacity (15.45 mg/g). SEM, N₂ adsorption-desorption isotherm, XRD, FTIR and XPS analysis suggested larger pore volume, relatively higher surface area, effective pore size distribution and abundant surface functional groups were the main reasons. Moreover, the influence of key adsorption parameters, including adsorbent dosage, initial pH, coexisting ions, ionic strength, contact time, initial TC concentration and ambient temperature had also been investigated. Results revealed that TC adsorption by 600AN were more consistent with pseudo-second order kinetic and Freundlich isothermal models. Combined with characterization results, which reasonably inferred that the adsorption mechanisms of 600AN were mainly involved pore-filling effect, hydrogen bonding interaction and π-π EDA interaction. This work has provided a low-cost, high efficiency and promising method for the dredged sediment reduction and resource recovery.