Removal of 2, 4-Dichlorophenoxyacetic Acid (2, 4-D) From Aqueous Environments Using Single-Walled Carbon Nanotubes

Background: 2, 4-Dichlorophenoxyacetic acid (2, 4-D) is a widely used herbicide known to be moderately toxic. Extensive use and poor biodegradability of 2, 4-D has resulted in its ubiquitous presence in the environment, and has led to contamination of surface and ground waters. Objectives: At present study, single-walled carbon nanotubes (SWCNTs) were used for the sorption of 2, 4-D from aqueous solutions. Materials and Methods: The effect of various operating parameters such as initial concentration of 2, 4-D, contact time, adsorbent dosage, and pH were investigated. Equilibrium isotherms were used to identify the possible mechanism of the adsorption process. Results: Maximum adsorption capacity of the SWCNTs was 979.6 mg/g at pH5, contact time 45 min, initial concentration of 5000 μg/L, and 23 ± 2 ◦C temperatures, when 97.96% of 2, 4-D herbicide were removed. The adsorption equilibriums were analyzed by Langmuir and Freundlich isotherm models. It was found that the data fitted to Langmuir (R2 = 0.9987) better than Freundlich (R2 = 0.9727) model. Conclusions: According to achieved results, it was defined that SWCNTs is a quite effective adsorbent in removal of 2, 4-D from aqueous environments.