Adsorption and removal of tetracycline antibiotics from aqueous solution by graphene oxide

TLDR: Graphene oxide is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution and has a better rate constant of sorption, 0.065 g mg(-1) h(-1), than other adsorbents.

Abstract: Significant concerns have been raised over pollution of antibiotics including tetracyclines in aquatic environments in recent years. Graphene oxide (GO) is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution. Tetracycline strongly deposited on the GO surface via π-π interaction and cation-π bonding. The adsorption isotherm fits Langmuir and Temkin models well, and the theoretical maximum of adsorption capacity calculated by Langmuir model is 313 mg g(-1), which is approximately in a close agreement with the measured data. The kinetics of adsorption fits pseudo-second-order model perfectly, and it has a better rate constant of sorption (k), 0.065 g mg(-1) h(-1), than other adsorbents. The adsorption capacities of tetracycline on GO decreased with the increase in pH or Na(+) concentration. The adsorption isotherms of oxytetracycline and doxycycline on GO were discussed and compared.