Adsorption and desorption of atrazine on carbon nanotubes

• Published in: Journal of colloid and interface science Vol. 321; no. 1; pp. 30 - 38
• Main Authors: Yan, X.M., Shi, B.Y., Lu, J.J., Feng, C.H., Wang, D.S., Tang, H.X.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-05-2008; Elsevier
• Subjects: Adsorption; Atrazine; Atrazine - chemistry; Atrazine - toxicity; Carbon nanotubes; Chemistry; Colloidal state and disperse state; Desorption; Exact sciences and technology; General and physical chemistry; Hysteresis; Models, Chemical; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - toxicity; Surface physical chemistry; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity; Water Purification; Carbon nanotubes; Desorption; Adsorption; Hysteresis; Atrazine
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2008.01.047

The potential impact of carbon nanotubes (CNTs) on human health and the environment is receiving more and more attention. The high surface area of CNTs tends to adsorb a large variety of toxic chemicals, which may enhance the toxicity of CNTs and/or toxic chemicals. In this study, adsorption and desorption of atrazine on carbon nanotubes from aqueous solution were studied through batch reactors. The adsorption equilibrium isotherms were nonlinear and were fitted by Freundlich, Langmuir, and Polanyi–Manes models. It was found that the Polanyi–Manes model described the adsorption process better than other two isotherm models. Together with the “characteristic curve,” the Polanyi adsorption potential theory is applicable to describe the adsorption process of atrazine on CNTs. Thermodynamic calculations indicated that the adsorption reaction of atrazine on CNTs is spontaneous and exothermic. The desorption data showed that no significant desorption hysteresis occurred. High adsorption capacity and adsorption reversibility of atrazine on CNTs suggest that CNTs have high health and environmental risks, whereas they have potential applications for atrazine removal from water.
Repetitive adsorption/desorption of atrazine on CNTs at three initial concentrations: 6.9 (■), 16.2 (▴), and 30.6 mg/L (●), the corresponding open symbols represent the desorption processes after the last adsorption step, respectively: (A) SMWNT20; (B) r-MWNT.