TY - JOUR
T1 - Removal of Synthetic Estrogen from Water by Adsorption on Modified Bentonites
AU - Gallouze, Halima
AU - Akretche, Djamal Eddine
AU - Daniel, Carla
AU - Coelhoso, Isabel
AU - Crespo, João G.
N1 - info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UID%2FQUI%2F50006%2F2019/PT#
H.G. gratefully acknowledges the Erasmus+ International Credit Mobility Program for her internship grant at LAQV, Department of Chemistry, Faculty of Science and Technology, University NOVA of Lisbon, Portugal.
PY - 2021/1
Y1 - 2021/1
N2 - Natural bentonite is an adsorbent that can be easily modified as a low-cost material effective for the removal of persistent pharmaceutical micropollutants from water bodies. In this study, the modification of untreated bentonite by sodium is addressed to obtain Na-bent, which was further modified with L-Tryptophan (L-Trp) as well as with FeCl2.4H2O to produce Trp-Na-bent and Fe-Na-bent, respectively. The nonmodified and modified bentonite samples were tested for the adsorption of the pharmaceutical micropollutant 17α-ethinylestradiol (EE2) present in water bodies, a synthetic estrogen with very high toxicity. The structure of bentonite, before and after modification, was characterized using Fourier transform infrared, X-ray diffraction, Brunauer-Emmett-Teller, and thermal analysis (thermogravimetric analysis and differential scanning calorimetry) techniques. The influence of various experimental parameters on the adsorbent/adsorbate interaction was investigated. Equilibrium and kinetic studies of EE2 micropollutant adsorption were performed varying the initial adsorbate concentration, mass of bentonite, and contact time. The maximum adsorption for an initial concentration of 10 mg/L of EE2 was 4.20 mg/g, reaching the equilibrium after 2 h. The equilibrium data were fitted with Langmuir, Freundlich, and Dual-mode model equations. Adsorption kinetic data were analyzed using the pseudo-first order, pseudo-second order, and intraparticle diffusion models. The pseudo-second order model was the one that better described the kinetic data. The highest value of the equilibrium rate constant was obtained for Trp-Na-bent, followed by Fe-Na-bent. The results obtained show that the Trp-Na-bent complex exhibits a promising performance for the adsorption of EE2.
AB - Natural bentonite is an adsorbent that can be easily modified as a low-cost material effective for the removal of persistent pharmaceutical micropollutants from water bodies. In this study, the modification of untreated bentonite by sodium is addressed to obtain Na-bent, which was further modified with L-Tryptophan (L-Trp) as well as with FeCl2.4H2O to produce Trp-Na-bent and Fe-Na-bent, respectively. The nonmodified and modified bentonite samples were tested for the adsorption of the pharmaceutical micropollutant 17α-ethinylestradiol (EE2) present in water bodies, a synthetic estrogen with very high toxicity. The structure of bentonite, before and after modification, was characterized using Fourier transform infrared, X-ray diffraction, Brunauer-Emmett-Teller, and thermal analysis (thermogravimetric analysis and differential scanning calorimetry) techniques. The influence of various experimental parameters on the adsorbent/adsorbate interaction was investigated. Equilibrium and kinetic studies of EE2 micropollutant adsorption were performed varying the initial adsorbate concentration, mass of bentonite, and contact time. The maximum adsorption for an initial concentration of 10 mg/L of EE2 was 4.20 mg/g, reaching the equilibrium after 2 h. The equilibrium data were fitted with Langmuir, Freundlich, and Dual-mode model equations. Adsorption kinetic data were analyzed using the pseudo-first order, pseudo-second order, and intraparticle diffusion models. The pseudo-second order model was the one that better described the kinetic data. The highest value of the equilibrium rate constant was obtained for Trp-Na-bent, followed by Fe-Na-bent. The results obtained show that the Trp-Na-bent complex exhibits a promising performance for the adsorption of EE2.
KW - adsorption modeling
KW - Algerian bentonite
KW - modified bentonite
KW - purification process
KW - synthetic estrogen removal
UR - http://www.scopus.com/inward/record.url?scp=85099740138&partnerID=8YFLogxK
U2 - 10.1089/ees.2020.0048
DO - 10.1089/ees.2020.0048
M3 - Article
AN - SCOPUS:85099740138
SN - 1092-8758
VL - 38
SP - 4
EP - 14
JO - Environmental Engineering Science
JF - Environmental Engineering Science
IS - 1
ER -