Adsorptive removal of tetracycline and lincomycin from contaminated water using magnetized activated carbon

Abstract

The release of antibiotics such as tetracycline (TC) and lincomycin (LM) used in livestock production into the environment and the development of antimicrobial resistance represents a great concern. To utilize the adsorption process for the removal of antibiotics and to facilitate separation of spent adsorbent from the treated water, a magnetized activated carbon (MAC) was developed using ultrasonic-assisted co-precipitation of iron oxide nanoparticles (γ-Fe2O3). The superparamagnetic properties of the adsorbent allowed a separation efficiency of 95 ± 3% from water, while magnetization changed the physiochemical properties of activated carbon including BET surface area, pore volume and PZC. The developed adsorbent was used for adsorption of TC from water at various concentrations and temperatures, and for simultaneous adsorption of TC and LM. The adsorption capacities of MAC toward TC either as an individual or in the presence of LM in water were slightly lower than that of AC, and the adsorption process had an endothermic nature. The adsorption capacities of MAC for TC was lower when LM was present in adsorption media (0.4 < qMixture,TC/qSingle,TC < 1.0), and vice versa. This indicates the competitive nature of TC and LM adsorption. The obtained data were fitted non-isothermally into different adsorption models (single and binary solute) and the associated coefficients were determined. Redlich–Peterson isotherm predicted the TC adsorption data in the range of 5–35 °C with accuracy and estimated the enthalpy change of adsorption as 54.3 kJ mol−1. Also, extended Langmuir model provided the most accurate prediction of the binary adsorption system.