Magnetic halloysite‐based molecularly imprinted polymer for specific recognition of sunset yellow in dyes mixture

• Published in: Polymers for advanced technologies 2021-02, Vol.32 (2), p.803-814
• Main Authors: Foroughirad, Sahar, Haddadi‐Asl, Vahid, Khosravi, Alireza, Salami‐Kalajahi, Mehdi
• Format: Article
• Language: English
• Subjects: Adsorption; Azo dyes; Chemical synthesis; Correlation coefficients; Dyes; Emission analysis; Field emission microscopy; Image transmission; Imprinted polymers; Isotherms; Langmuir adsorption isotherm; magnetic halloysite nanotube; Magnetometers; molecularly imprinted polymer; pseudo‐second order kinetic; Recognition; selectivity; sunset yellow; Temperature effects; Thickness; Zeta potential
• ISSN: 1042-7147; 1099-1581
• DOI: 10.1002/pat.5132

Novel magnetic halloysite‐based molecularly imprinted polymer (MMIP) is fabricated for sunset yellow dye removal from water solution. Field emission scanning electron microscopy, vibrating sample magnetometer, Zeta potential test, thermogravimetric, and nitrogen gas adsorption analysis were all employed for characterizations of the obtained magnetic halloysite and the final adsorbent. Transmission electron microscope images proved the synthesis of polymeric shell onto the magnetic nanotubes with the thickness of 10 nm. The adsorption kinetics were assessed by pseudo‐first order, pseudo‐second order, and intraparticle diffusion models and the results revealed that the obtained MMIP adsorption procedure would be controlled by chemical adsorption due to the high correlation coefficient (R2 ≥ 0.99) achieved for pseudo‐second order model. The effect of dye initial concentration was observed on the pseudo‐second order rate constant and the final equilibrium capacity of the MMIP. The adsorption isotherm at different temperatures (30 and 60°C) was assessed by two popular models, Langmuir and Freundlich. The resulting data were well fitted by Langmuir isotherm model, suggesting that the monolayer adsorption of sunset yellow onto the MMIP would occur. The exothermic behavior of the adsorption was justified by determining the effect of temperature on the Langmuir isotherm constant. The fabricated MMIP represented high adsorption capacity and imprinting factor of 46.43 μmol/g and 1.33, respectively. Moreover, the high selective recognition ability toward sunset yellow was observed for MMIP in the dyes mixture solution.