High-swelling β-cyclodextrin polymer as a high-affinity adsorbent for rapid removal of pollutants in water

Abstract Global water pollution with thousands of industrial and natural chemical compounds, such as drugs, endocrine disruptors, dyes and metal ions, has raised concerns about the potential negative effects on aquatic ecosystems and human health. Renewable adsorbents with rapid adsorption and high capacity are highly desirable for water treatment. Here, we report a high-swelling β-cyclodextrin polymer with flexible chelating groups, providing multiple active adsorption sites and high specific surface area after swelling that has high affinity and binding energy for different types of pollutants in water. Its adsorption rate for MB, BPA, Cu2+ is 106-470 times, 5-15 times, 14-23 times and adsorption capacity is 1-7 times greater than those of activated carbons and low-swelling β-cyclodextrin polymers. The adsorbent is low cost, regenerates under mild conditions, and rapidly removes mixed contaminants at environmentally relevant concentrations. For a large-scale purification of polluted lakes, for example, 3.78×107 m3 water storage capacity (Ya-Er Lake in Wuhan), the cost using our adsorbent is about 0.45 million USD (excluding labor cost), which is far less than the budgeted oxidation treatment cost of 56.83 million USD. Our findings demonstrate the promise of high-swelling cyclodextrin-based polymers for rapid, high-capacity purification of tap water, treatment of industrial wastewater, and remediation of contaminated surface water.