Synthesis of new polyester networks containing β-cyclodextrin cavities for removal of paraben derivatives from water resources by inclusion complexes

This study aimed to develop new thermally stable synthetic polyester network containing β-cyclodextrin (β-CD) cavities with good absorbent behavior to remove organic pollutants such as parabens derivatives (methyl and propyl parabens) from aqueous solution. β-Cyclodextrin polyester network (β-CDPN) was synthesized by the reaction of β-CD with N,N′-(4,4′-diphenylether) bis trimellitimide diacid chloride as a cross-linker agent in the presence of sodium hydride. Diimide acid chloride as a synthetic cross-linker agent was prepared by two-step reactions. The sorbent process was optimized by four different parameters, such as pH, the temperature of the solution, contact time, β-CDPN ratio. After adsorbed of parabens in aqueous solution, the β-CDPN precipitates were gathered, and the solution was analyzed by using the high-performance liquid chromatography (HPLC) technique. The results show the high absorbent capacity of parabens (about 99%) by β-CDPN cavities. Furthermore, the kinetic data were measured using the pseudo-first-order and pseudo-second-order equation. The pseudo-second-order showed the best fit for the kinetic studies (methyl and propyl parabens R2: 0.9979 and 0.9998, respectively). The adsorption equilibrium of methyl paraben using β-CDPN could be well defined with the Langmuir isotherm model. The adsorption ability of β-CDPN kept nearly unchanged after five filtration-regeneration cycles, further TGA and DTG experiments show β-CDPN has excellent thermal stability and can be used in a wide range of temperatures.