Efficient Removal of Cr(VI) from Aqueous Solutions by a Dual‐Pore Covalent Organic Framework

Removal of hexavalent chromium (Cr(VI)) from water is of great importance because of its enormous threat to water ecological environment and human health. Adsorption of Cr(VI) by porous materials is a promising technique to address this issue. However, to develop adsorbents with rapid uptake and high capacity remains a challenge. Herein, the great potential of covalent organic frameworks (COFs) is demonstrated for the adsorption of Cr(VI) in aqueous solutions. A novel dual‐pore COF bearing hydroxyl groups is synthesized and exploited to remove chromate from aqueous solutions. It exhibits a fast removing process (272 Cr mg g−1 within 10 min), with a maximum adsorption capacity up to 384 Cr mg g−1, which is among the highest ones reported for porous materials so far. A mechanistic study reveals that the hydroxyl groups on the backbone of the COF play a critical role for the capture of Cr (VI).