Phytoremediation of Methylene Blue and Congo Red by duckweed (Lemna minor)

Abstract

Synthetic colorants are widely used globally by different industries for the dyeing process. However, these chemicals pollute the environment and affect human health by causing allergies, hives, dermatitis, and cancer. This study aims to compare the effectiveness of duckweed (Lemna minor) in the removal of the Methylene Blue (MB) and Congo red (CR) dyes at different concentrations (1 mg/L, 5 mg/L, 10 mg/L, and 15 mg/L). Absorbance values were determined at 665 nm for MB and 497 nm for CR after 96 hours. The results show higher removal of MB compared to CR for all concentrations (95.49 % vs. 59.32%, 1 mg/L; 97.24% vs. 39.43%, 5mg/L; 91.30% vs 28.47%, 10mg/L; y 85.42% vs 20.27%, 15mg/L). The removal of MB was observed after 30 min of contact with duckweed, while the removal of CR was observed after 24 hours in all concentrations.

Keywords

• Methylene blue; Congo Red; phytoremediation; Lemna minor; duckweed; textile dyes