Evaluating the Efficiency of Rhamnolipid in Removing Atrazine and 2,4-D From Soil

• Published in: Journal of polymers and the environment 2024-04, Vol.32 (4), p.1672-1683
• Main Authors: Braz, Letícia Martini, Goda, Ricardo Tadashi, Teixeira, Jéssica, de Alencar, Ridien Gonçalves, Giovanni Freschi, Gian Paulo, Brucha, Gunther, Andrade, Grazielle Santos Silva, Tambourgi, Elias Basille
• Format: Article
• Language: English
• Subjects: 2,4-D; Atrazine; Biosurfactants; Carbon sources; Chemistry; Chemistry and Materials Science; Desorption; Environmental Chemistry; Environmental Engineering/Biotechnology; Herbicides; Industrial Chemistry/Chemical Engineering; Materials Science; Multilayers; Original Paper; Pesticides; pH effects; Pollutant removal; Polymer Sciences; Rhamnolipids; Soil contamination; Soil pollution; Soil remediation; Surfactants; Tropical environments; Tropical soils
• ISSN: 1566-2543; 1572-8919
• DOI: 10.1007/s10924-023-03069-5

The present work investigates how rhamnolipid biosurfactants perform when removing the pesticides atrazine and 2,4 D from an artificially contaminated tropical soil. The rhamnolipid was produced by Pseudomonas aeruginosa , using molasses 7% m/v as a carbon source. The red‒yellow latosol, a tropical soil, went through a physical-chemical characterization and then was artificially contaminated with the herbicides. The value of 19.82 mL/g indicated high affinity to 2,4 D by the latosol, contrary to atrazine, having only a = 0.83 mL/g. The desorption tests in contaminated soil indicated that the presence of biosurfactants enhances pesticide removal, and was influenced by the pH and biosurfactant concentrations. Both pesticides attained greater values of desorption at a higher biosurfactant concentration of 5 CMC (900 mg/L), but at different pHs. From atrazine, a higher value of desorption, 25.66 mg/kg, was attained at a pH of 7.0. From 2,4 D, however, a desorption of 13.17 mg/kg was attained at a pH of 9.0. The Gunary model was shown to be the best-fitting model for both pesticides when analyzing experimental data, indicating a multilayer desorption process. The results indicate that rhamnolipids are a promising alternative in Surfactant-enhanced remediation (SER), contributing to the recovery of pesticide-contaminated soils.