## 1 Introduction  
In recent years, researchers have shown concern about the fate, transport, reactivity and bioavailability of organic micro-pollutants (OMPs) [1, 2]. Among these OMPs, endocrine disrupting chemicals (EDCs) can imitate the biological activity of natural hormones, occupy the hormone receptors, or interfere with the body's hormonal system, which can pose health risks to animals and humans [3]. Bisphenol A (2,2-bis(4-hydroxyphenyl) propane; BPA), one of these EDCs, is widely used as an important monomer for the production of plastics [4]. It is also extensively used in adhesives, plasticizers and polymerization inhibitors. The global demand for BPA is growing fast. The US market was growing at about 4.2% yearly up to 2010, with the growth of polycarbonates and epoxyresins. In Europe, the demand is expected to remain steady while the strongest growth will be in China [5]. The widely used BPA products lead to a gradual release of BPA into the environment, where it is frequently detected in industrial wastewater, groundwater, surface water, and even drinking water [6; 7]. Therefore, efficient treatment processes have to be developed for the removal of BPA.  
Currently, various technologies are being used to remove BPA from water, including adsorption [8; 9], membrane separation [10], biological treatment [11], oxidation degradation [4], and other processes. Among these methods, adsorption has been found to be superior to other techniques for BPA removal based on low cost, flexibility, and fewer harmful secondary products [12]. A large number of adsorbents have been studied for the removal of BPA, such as active carbon [8], graphene [13], carbon nanotubes (CNTs) [14], resin polymers [15], mineral materials [16], etc. However, the use of these adsorbents on a large scale is limited by the difficulties of separation and regeneration. In order to solve the difficulty in collecting adsorbents from their dispersing media, much attention has been paid to the combination of magnetic nanoparticles and conventional adsorbents. [PERSON] et al. [17] prepared a recyclable magnetic carbon nanotube (CNTs/Fe\({}_{3}\)O\({}_{4}\)) for removing BPA from water. [PERSON] et al. [18] synthesized the chitosan/fly-ash-cenospheres/\(\gamma\)-Fe\({}_{2}\)O\({}_{3}\) (CTS/\(\gamma\)-Fe\({}_{2}\)O\({}_{3}\)/FACs) magnetic composites for the removal of BPA from aqueous solutions. [PERSON] et al. [19] utilized thiol functionalized superparamagnetic nanoparticles to remove heavy metals from aqueous systems. Polydivinylbenzene magnetic latex particles were prepared for the removal of BPA and some heavy metal ions [20]. Moreover, [PERSON] et al. [21] found that magnetite nanoparticles (Fe\({}_{3}\)O\({}_{4}\) MNPs) exhibited ultrahigh adsorption towards chlorotetracycline, and many other studies suggested that the magnetic composite adsorbent could remove pollutants [22; 23; 24]. These adsorbents not only possessed the adsorption advantages of the monomer, but also could be easily separated from the solutions by an external magnet. Research indicated that the 2-vinylpyridine (2-VP) polymer had a high adsorption capacity towards aromatic acids and metal ions [25; 26]; 2-VP is also a good hydrogen bonding acceptor [27]. The composite adsorbent of 2-VP and Fe\({}_{3}\)O\({}_{4}\) may have better adsorption performance. However, to our knowledge, no relevant work regarding the application of a 2-VP and Fe\({}_{3}\)O\({}_{4}\) composite adsorbent for BPA removal has been reported.  
The objective of the present study was to study: (1) the preparation and physicochemical properties of a composite adsorbent of 2-VP and Fe\({}_{3}\)O\({}_{4}\) (Mag-PVP); (2) the adsorption behavior of Mag-PVP for the removal of BPA from aqueous solution, analyzing the influence of the chemistry of solution (ionic strength, humic acid, and pH) on this process; (3) the adsorption characteristic and mechanism.