Graphene oxide as a new generation adsorbent for the removal of antibiotics from waters

ABSTRACT

The presence of antibiotic molecules in the natural water sources is currently a huge problem due to the development of bacterial resistance. Graphene oxide (GO) has a large potential as a candidate for the applications of water treatment. In this paper, graphene oxide was tested as a new generation adsorbent for the removal of two antibiotics: trimethoprim (TMP) and isoniazid (INH). Both adsorption processes reached the equilibrium in less than 1 h. Maximum adsorption capacities were found to be 204.08 mg g^-1 for TMP and 13.89 mg g^-1 for INH. TMP adsorption on GO was favored in alkaline medium while the performance of GO for INH adsorption was better in acidic conditions.

KEYWORDS:

• Antibiotics removal
• graphene oxide
• waste water treatment
• trimethoprim
• isoniazid

Novelty statement

The development of antibiotics has huge contribution in the treatment of bacterial infectionsand saving human life. However, the disposed antibiotics in the waters may lead to the growth of antibiotic-resistant bacteria, which will reduce the treatment efficiency of existing antibiotics. Two of the widely used antibiotics, trimethoprim (TMP) and isoniazid (INH) have been detected from the aqueous environment at least since mid-1990s. Because of the poor metabolism and slow degradation, removing of these antibiotics from waters by effective adsorbents becomes necessary. In previous studies, Graphene oxide (GO) has been successfully used as the absorbent to remove heavy metal ions from aqueous solutions. GO was selected as a new generation adsorbent due to its high theoretical surface area and functional groups attached. In this work, experiments were designed to study the usage of GO as the absorbent to remove TMP and INH from aqueous solution. Besides the adsorption kinetics and equilibrium isotherm models, other factors that may affect the adsorption, such as pH value, were also studied. Based on the experimental results at different conditions, GO has been proved to be a good adsorbent for TMP, especially in alkaline medium, and a modest adsorbent for INH in acidic medium. This work has tested GO as the adsorbent for TMP and INH; and showed the potential applications of GO as adsorbent for other similar antibiotics.