Optimizing Adsorption of 17α-Ethinylestradiol from Water by Magnetic MXene Using Response Surface Methodology and Adsorption Kinetics, Isotherm, and Thermodynamics Studies.

Mengwei Xu,Zhoufei Luo,Zihan Wu,Hui Li,Langtao Xiao,Chao Huang,Xianxin Zhu,Jing Lu

doi:10.3390/molecules26113150

Mengwei Xu, Zhoufei Luo + Show 6 more

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https://doi.org/10.3390/molecules26113150

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Journal: Molecules (Basel, Switzerland)	Publication Date: May 25, 2021
Citations: 10	License type: CC BY 4.0

Affiliation: Hunan Agricultural University

Abstract

Magnetic MXene composite Fe3O4@Ti3C2 was successfully prepared and employed as 17α-ethinylestradiol (EE2) adsorbent from water solution. The response surface methodology was employed to investigate the interactive effects of adsorption parameters (adsorption time, pH of the solution, initial concentration, and the adsorbent dose) and optimize these parameters for obtaining maximum adsorption efficiency of EE2. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) and t-test statistics. Optimization of the process variables for maximum adsorption of EE2 by Fe3O4@Ti3C2 was performed using the quadratic model. The model predicted maximum adsorption of 97.08% under the optimum conditions of the independent variables (adsorption time 6.7 h, pH of the solution 6.4, initial EE2 concentration 0.98 mg L−1, and the adsorbent dose 88.9 mg L−1) was very close to the experimental value (95.34%). pH showed the highest level of significance with the percent contribution (63.86%) as compared to other factors. The interactive influences of pH and initial concentration on EE2 adsorption efficiency were significant (p < 0.05). The goodness of fit of the model was checked by the coefficient of determination (R2) between the experimental and predicted values of the response variable. The response surface methodology successfully reflects the impact of various factors and optimized the process variables for EE2 adsorption. The kinetic adsorption data for EE2 fitted well with a pseudo-second-order model, while the equilibrium data followed Langmuir isotherms. Thermodynamic analysis indicated that the adsorption was a spontaneous and endothermic process. Therefore, Fe3O4@Ti3C2 composite present the outstanding capacity to be employed in the remediation of EE2 contaminated wastewaters.

Highlights

The proposed Box–Behnken designs (BBD) approach provided a critical analysis of the interactive influences of the selected variables on the EE2 adsorption process of adsorbent. pH was the most significant parameter in the EE2 adsorption process
The model predicted values were in good agreement with the experimentally determined values
The Response surface methodology (RSM) approach successfully reflects the impact of various factors, and the established model well agrees with the actual situation

Summary

Introduction

The synthetic estrogenic steroid 17α-ethynilestradiol (EE2), the active ingredient of most contraceptive medicine, has been widely used to adjust the animal or human pregnancy and reproduction [1]. The treated effluent from animal excrete always contains. EE2 and makes the effluents become a major pathway for introducing EE2 into the aquatic environment [2]. EE2 has been widely distributed in surface waters with a detectable concentration in the world [3,4]. With its ubiquitous occurrence and high endocrine disrupting potency, EE2 has become a widespread problem in the aquatic environment [7]. It is highly desirable to remove the EE2, in particular, from water or wastewater

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