Removal of antibiotics from pharmaceutical wastewater using Lemna Aoukikusa (duckweed)

Abstract

Duckweed (Lemna aoukikusa), a common aquatic plant found worldwide, was used to treat a solution polluted with the model antibiotics, ciprofloxacin (fluoroquinolone group) and sulfamethoxazole (sulfonamide group), which were selected because they were frequently present in pharmaceutical wastewater. The plant could grow even in an aqueous solution with a high concentration of both antibiotics, and illumination enhanced its growth. The presence of antibiotics in the solution inhibited the growth, and the inhibitory effect of sulfamethoxazole was greater than that of ciprofloxacin. Ciprofloxacin was effectively reduced by hydrolysis, photolysis, and uptake by the duckweed. Although sulfamethoxazole was resistant to hydrolysis and photolysis, its uptake by duckweed under illumination conditions could remove both antibiotics from the solution, even at high concentrations. Regarding the contribution of the respective types of antibiotic removal rates to total antibiotic removal, the uptake rate of antibiotics was the highest, and the treatment of wastewater using duckweed was proposed as a promising treatment method.