Novel effective dye sorbents: synthesis and properties of 1,2,3-triazole-modified thiacalix[4]arene polymers based on click chemistry

By introducing 1,2,3-triazole-ester groups on thiacalix[4]arene based on click chemistry and then ammonolysis with ethylenediamine, diethylenetriamine or triethylenetetramine, three novel 1,2,3-triazole-modified thiacalix[4]arene polymers were conveniently prepared in “4+2” condensation mode in ideal yields. The structures of polymers 4a–4c were confirmed by elemental analysis, FTIR and 1H NMR spectra. The surface morphologies of polymers 4a–4c were investigated by SEM micrographs. The Mn of novel polymers 4a–4c indicated approximately 18–20 calixarene units in each polymer molecule. The dye adsorption abilities of polymers 4a–4c for series of organic dyes (alizarin green, orange I, neutral red (NR), Congo red (CR), orange G (OG), crystal violet, Victoria blue B and methylene blue) were studied by solid–liquid adsorption experiments. The adsorption experimental results implied that they had excellent adsorption abilities for tested organic dyes. The highest adsorption percentage reached 97 % for OG. The best saturation adsorption capacities for NR and CR were as high as 1.282 and 1.407 mmol/g, respectively. These novel polymers possessed stable adsorption abilities in the scopes of pH 5–9 and had good reused properties after desorption. The adsorption mechanism proposed that not only dipole interaction, electrostatic interaction and hydrogen bonding interaction, but also the π–π stacking interaction plays important role in binding dyes.