Multifunctional β-Cyclodextrin Polymer for Simultaneous Removal of Natural Organic Matter and Organic Micropollutants and Detrimental Microorganisms from Water

Natural organic matter (NOM), organic micropollutants (OMPs), and detrimental microorganisms are three major pollutants that affect water quality. To remove these pollutants, a quaternary ammonium-functionalized β-cyclodextrin polymer (β-CDP) is successfully synthesized in the aqueous phase. The N2 and CO2 adsorption/desorption analysis showed that the polymer mainly contains ultra-micropores (<1 nm), with a Langmuir surface area of 89 m2 g-1. Two kinds of NOM, humic acid and fulvic acid, and five OMPs, 2-naphthol (2-NO), 3-phenylphenol (3-PH), 2,4,6-trichlorophenol (2,4,6-TCP), bisphenol A (BPA), and bisphenol S (BPS), were selected as model pollutants to study the performance of β-CDP and three kinds of commercial adsorbents, including granular activated carbon, DARCO-AC, and two resins, XAD-4 and D-201, were used for comparison. The polymer shows ultrarapid adsorption kinetics for the removal of these pollutants, with pseudo-second-order rate constants two to three orders of magnitude higher than that of the commercial activated carbon and resins. Due to the different adsorption sites of NOM and OMPs, β-CDP can simultaneously remove these pollutants without competitive adsorption. The maximum adsorption capacity of β-CDP for HA, FA, 2-NO, 3-PH, 2,4,6-TCP, BPA, and BPS based on the Langmuir model is 40, 166, 74, 101, 108, 103, and 117 mg g-1, respectively. After use, the polymer can be easily regenerated at room temperature. In addition, β-CDP also showed excellent bactericidal properties due to the quaternary ammonium groups. At a concentration of 15 g L-1, β-CDP can remove 98% of the tested Escherichia coli. Moreover, the synthesis of β-CDP is simple, green, and easy to industrialize. All of these findings indicate that β-CDP, as an ideal multifunctional material, presents potential for practical applications for water treatment and disinfection.