Assessment of chitosan-based adsorbents for glyphosate removal

Abstract

Exposure to glyphosate produces various toxic effects, due to this, different methods have been evaluated for its elimination. The objective of this work was to formulate chitosan-based adsorbents and evaluate their efficiency in the removal of glyphosate in vitro. Four films were made by varying the weight ratio of silica/chitosan particles, and four sponges were made by varying the chitosan/chitosan ratio in a reticulated manner. Both adsorbents were characterized based on their porosity, water absorption, glyphosate removal, and reusability. It was found that increasing the porosity in both films and sponges resulted in an increase in the adsorption efficiency of glyphosate. The adsorption process exhibited a better fit in both adsorbents to the pseudo-second-order model. The adsorption of glyphosate to the films fit better with the Langmuir model, demonstrating that the process occurs in the form of a monolayer. In the case of sponges, the adsorption of glyphosate fit better with the Freundlich model, indicating that the process takes place in a multilayer form. Finally, when the reusability was evaluated, the adsorbents showed a loss of effectiveness. However, they still proved to be an efficient alternative for the removal of glyphosate in water, providing a cost-effective and environmentally friendly solution.

Keywords:

• Adsorption
• films
• sponges
• chitosan
• removal
• glyphosate

Acknowledgments

The authors kindly acknowledge to CONAHCyT from Mexico, for the graduate scholarships of authors KG Zavala-Robles.

Disclosure statement

The authors declare no conflicts of interest.

Data availability statement

Data available on request from the authors

Additional information

Funding

CONSEJO NACIONAL DE HUMANIDADES CIENCIA Y TECNOLOGIA (CONAHCYT).