Efficient Removal of Tetracycline from Aqueous Media with a Fe(3)O(4) Nanoparticles@graphene Oxide Nanosheets Assembly

A readily separated composite was prepared via direct assembly of Fe(3)O(4) magnetic nanoparticles onto the surface of graphene oxide (GO) (labeled as Fe(3)O(4)@GO) and used as an adsorbent for the removal of tetracycline (TC) from wastewater. The effects of external environmental conditions, such as pH, ionic strength, humic acid (HA), TC concentration, and temperature, on the adsorption process were studied. The adsorption data were analyzed by kinetics and isothermal models. The results show that the Fe(3)O(4)@GO composite has excellent sorptive properties and can efficiently remove TC. At low pH, the adsorption capacity of Fe(3)O(4)@GO toward TC decreases slowly with increasing pH value, while the adsorption capacity decreases rapidly at higher pH values. The ionic strength has insignificant effect on TC adsorption. The presence of HA affects the affinity of Fe(3)O(4)@GO to TC. The pseudo-second-order kinetics model and Langmuir model fit the adsorption data well. When the initial concentration of TC is 100 mg/L, a slow adsorption process dominates. Film diffusion is the rate limiting step of the adsorption. Importantly, Fe(3)O(4)@GO has good regeneration performance. The above results are of great significance to promote the application of Fe(3)O(4)@GO in the treatment of antibiotic wastewater.