Polydopamine/β-cyclodextrin/coal fly ash composite for the highly efficient extraction of uranium from water environment

•A green, low-cost and efficient adsorbent, polydopamine/β-cyclodextrin polymer/coal fly ash composite (PDA/β-CD/CFA), was first prepared to extract uranium.•The introduce of β-CD and PDA could not only enhance the hydrophily of CFA, but also bring abundant functional groups with good affinities to uranyl ions, like -NH2/NH.•The desorption efficiency of uranium by PDA/β-CD/CFA was still more than 90% after five cycles.•Uranium was mainly adsorbed by PDA/β-CD/CFA through chelation, complexing action, electrostatic interaction and hydrogen bonding.