Materials Today Communications xxx (xxxx) xxx Please cite this article as: Sahar Foroughirad, Materials Today Communications, https://doi.org/10.1016/j.mtcomm.2020.101780 Available online 22 October 2020 2352-4928/© 2020 Elsevier Ltd. All rights reserved. Effect of porogenic solvent in synthesis of mesoporous and microporous molecularly imprinted polymer based on magnetic halloysite nanotubes Sahar Foroughirad a , Vahid Haddadi-Asl a, *, Alireza Khosravi a , Mehdi Salami-Kalajahi b, c a Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran b Faculty of Polymer Engineering, Sahand University of Technology, P.O. Box 51335-1996, Tabriz, Iran c Institute of Polymeric Materials, Sahand University of Technology, P.O. Box 51335-1996, Tabriz, Iran A R T I C L E INFO Keywords: Molecularly imprinted polymer Dye adsorption Halloysite nanotubes Intra-particle diffusion Adsorption isotherms Water treatment ABSTRACT A novel water-compatible magnetic molecularly imprinted polymer (MMIP) was fabricated for sunset yellow dye removal by surface imprinting approach. The magnetic halloysite nanotubes were prepared by co-precipitation method and used as support for surface polymerization. The synthesis of Fe 3 O 4 nanoparticles on the halloysite nanotubes were confrmed by X-Ray Diffraction (XRD) and energy dispersive spectroscopy (EDS). Water and ethanol were used as polymerization solvents and the effect of porogenic solvent was investigated on fnal adsorption behavior of the polymers. The Brunauer-Emmett-Taller (BET) and Barrett-Joyner-Halenda (BJH) techniques were employed for surface area and pore diameter assessments. The MMIP synthesized in water (W- MMIP) showed higher adsorption capacity (46.4 μmol/g) and selectivity (K sel = 3.60) toward sunset yellow dye. The adsorption kinetic data were well-ftted by pseudo-second-order kinetic model representing the chemi- sorption of dye molecules onto the specifc recognition sites of MMIPs. The intraparticle diffusion was assessed by Morris-Weber kinetic plots. The experimental data were assessed by the Langmuir and Freundlich adsorption Isotherm models. 1. Introduction Researches based on dye removal and wastewater treatment have witnessed a tremendous growth in the recent years. The used dyes which are released into water are believed to have crucial effects on aquacul- ture and human beings. That is why the dye elution methods have become a widespread topic among researchers [1,2]. Synthetic dyes are used in different industries including textile, printing, paper, food, and cosmetics and there may be even a rise in their applications in near future [3]. Approximately, 70 % of the all synthetic dyes used in different industries are azo dyes [4]. These groups of dyes are named regarding to the chromophoric compound of azo (-N = N-) in which two nitrogen atoms are bonded to each other with a double bond [5]. Food colorants are used to enhance the food appearance and acceptability by covering the probable defects and inducing the desired favor. Sunset Yellow FCF (C.I. 15,985), which can be classifed as sul- phonic acid azo dyes, is the most commonly used synthetic dye in Iran’s food productions. This yellow-orange colorant can be found in drinks, jelly products, snacks, etc. [6]. Although this food colorant is believed to be safe to human with the daily uptake limit of 100200 ppm, several toxicity researches have clarifed mutagenic and carcinogenic potentials [7], allergenic and asthma side effects [1], and even some DNA damage inductions [8]. Several techniques have been applied to detect and remove dyes and ions from aqueous solutions including high perfor- mance liquid chromatography [9], cloud point extraction [10], elec- trodegradation [11], and polymeric adsorbents [12,13]. In comparison to the all applied methods for dye removal, molecu- larly imprinted polymers (MIPs) are one of the most promising ap- proaches due to their unique properties [14–17]. Low production cost, High effciency, sustainability in both acidic and basic conditions, high temperature and mechanical resistance, and reusability are some of the intriguing characteristics of MIPs [18,19]. MIPs are synthesized and employed for specifc recognition and elimination of pollutants, including dyes in wastewater systems [20]. The presence of the template molecule, such as SY, during the polymerization process enhances the interaction between the functional groups of the monomer and the template. The template is then eliminated from the 3D structured cross-linked polymer, resulting in some cavities. These active sites are expected to have high affnity to the template molecules, as they would have the same shape and topology of the template [21,22]. The * Corresponding author. E-mail address: haddadi@aut.ac.ir (V. Haddadi-Asl). Contents lists available at ScienceDirect Materials Today Communications journal homepage: www.elsevier.com/locate/mtcomm https://doi.org/10.1016/j.mtcomm.2020.101780 Received 11 August 2020; Received in revised form 28 September 2020; Accepted 16 October 2020