Adsorptive removal of α-endosulfan from water by hydrophobic zeolites. An isothermal study.
This paper deals with the removal of α-endosulfan from water over HY and steamed HBEA zeolites. Experiments were performed to understand the adsorption mechanisms of α-endosulfan on zeolites and to determine the most efficient adsorbent for the purification of water contaminated by this pesticide. The experiments exhibit that α-endosulfan was adsorbed in the micropores. In the case of HY zeolites an adsorption of α-endosulfan molecules on BrØnsted sites was pointed out, due to a preferential water adsorption in mesopores. Moreover a physisorption of α-endosulfan occurred in micropores. For steamed HBEA zeolites physisorption in micropores was pointed out as the adsorption mode. For both types of zeolites a decrease of the adsorption capacities was noticed when the acidity of zeolites increased. There was also a linear relation between the adsorption capacities of α-endosulfan and the hydrophobicity (HI) of the samples and by determining the values of HI for a type of zeolite it was possible to deduce the uptake of α-endosulfan. The HY(40) sample was the most efficient for the removal of α-endosulfan from water because of preferential adsorption of water molecules in mesopores and lower acidity. For this sample the adsorption capacity for α-endosulfan was about 833.33 mg/g where for the most effective HBEA sample (St700(3)) the adsorption capacity was about 793.65 mg/g.
Laboratoire de Physique et de Chimie de l'Environnement (LPCE), Université de Ouagadougou, UFR SEA 03 BP 7021, Ouagadougou 03, Burkina Faso. yarsene@hotmail.com
Arsène H
AH
Yonli
Isabelle
I
Batonneau-Gener
Jean
J
Koulidiati
D000327:Adsorption; D004726:Endosulfan / Q000302:isolation & purification*; D010575:Pesticides / Q000302:isolation & purification*; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D017641:Zeolites / Q000737:chemistry*
D010575:Pesticides; D014874:Water Pollutants, Chemical; D017641:Zeolites; D004726:Endosulfan