Potential of rice husk ash in atrazine removal

ABSTRACT

An experimental study was carried out to explore the possibility of using a prepared microporous material, Rice Husk Ash (RHA) as an alternative to the commercial Powdered Activated Carbon (PAC), to remove atrazine (ATZ) pesticide from aqueous solution. The effects of contact time and pH on the adsorption were studied using the batch technique. Based on Hückel model calculations, the zwitterion behaviour of atrazine molecule was proved to be related to the pH of zero charge point of adsorbents (6.8 for RHA and 8.2 for PAC). The results showed that the Pseudo Second Order model is applicable to both adsorbents, suggesting that chemisorption is the rate-limiting step. The equilibrium data fitted well with the Langmuir model in the case of RHA, whereas the Freundlich model better fitted the equilibrium data in the PAC case, suggesting the existence of multi-layer adsorption of atrazine. The adsorption for RHA was found to be feasible and spontaneous, with a removal capacity of atrazine of more than 7 mg g⁻¹. With regard to the BET surface, this removal capacity (50.5 µg_ATZ / m²_RHA) was 25% better than that PAC (37.75µg_ATZ / m²_PAC).

KEYWORDS:

• Pesticide
• sorption
• atrazine
• rice husk Ash
• powder-activated carbon

Acknowledgments

The authors wish also to thank Pr. Sonia Dridi-Dhaouadi from Institut Préparatoire aux Etudes d’Ingénieurs de Monastir, Tunisia, for advices and constructive discussions and revision, Pr. Hervé Muhr and M. Kevin Mozet form LRGP, Nancy France for MEB slides and BET analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

A.D. N'Diaye is a doctor of chemistry of the University of Monastir (Tunisia) since July 2018. Since 2012, he has been head of the Toxicology and Quality Control Department at the National Institute of Public Health Research in Nouakchott, Mauritania.

C. Boudokhane is a doctor of chemistry of Pierre and Marie Curie University (France) since April 1990. Currently he is a lecturer at the Faculty of Pharmacy of Monastir (Tunisia).

M. Kankou is a doctor of Chemistry and Microbiology of Water from the University of Limoges (France) since June 2004. He is currently Professor of Chemistry at the Faculty of Science and Technology of Nouakchott (Mauritania).

H. Dhaouadi is Doctor of Process Engineering of the National Polytechnic Institute of Loraine (France) since April 1997. He is Director of the Research Unit UR13ES63 of Applied Chemistry and Environment at the Department of Chemistry of the Faculty of Sciences of Monastir, where he is Professor since January 2012.

Additional information

Funding

The authors express their gratitude to the Tunisian Higher Education and Scientific Research Ministry for the financial support.