Hierarchically micro-mesoporous β-cyclodextrin polymers used for ultrafast removal of micropollutants from water

Persistent organic pollutants, including plasticizers, pesticides, pharmaceuticals and endocrine disrupters, have posed a serious threat to water safety and human health. Addressing this problem calls out new materials of purifying water with high efficiency. Here, a series of cross-linked β-cyclodextrin polymers (β-CDPs) with hierarchically micro-mesoporous structure and high surface area were first synthesized by introducing polymer of intrinsic microporosity (PIM) and used for adsorptive removal of organic micropollutants from water. The chemical compositions and porous structures of the obtained β-CDPs were characterized in detail. Adsorption data showed that the quasi-second-order adsorption rate constant and maximal adsorption capacity of β-CDPs towards bisphenol A was up to 3.88 g mg^-1 min^-1 and 502 mg g^-1, almost 2.6 and 5.7 times as large as those of the state-of-the-art porous β-CD polymer, respectively. Further, hierarchically porous β-CDPs also demonstrated ultrafast adsorption rates and high adsorption capacities towards various organic pollutants under the synergistic effect of micropores and mesopores. In addition, β-CDPs were easily regenerated by simple ethanol cleaning and kept high removal ability over 5 cycles. The virtues of extraordinary adsorption ability and convenient regeneration offer β-CDPs potential applications in water purification.