Water-insoluble β-cyclodextrin-based nanocubes as cost-effective adsorbents for dyeing wastewater remediation with high selectivity

Water contamination caused by the discharge of textile dyeing wastewater is a thorny issue that cannot be ignored nowadays. In this work, eco-friendly beta-cyclodextrin based nanocubes (cl-CD@CA) with low cost and exceptional adsorption capacity were fabricated by a facile method to treat textile dyeing effluents. The prepared adsorbents showed high water insolubility and extraordinary adsorption capacity towards methylene blue, crystal violet, neutral red, Pb2+, Cd2+, and Sb3+ ions with corresponding maximum adsorption capacity of 1523.6, 1012.2, 419.2, 758.7, 525.3, and 398.1 mg/g, much higher than that of some other adsorbents. The adsorption kinetic and isotherm studies indicated that the adsorption process of cl-CD@CA fit pseudo-secondorder adsorption kinetic model and Langmuir isotherm model well, manifesting its monolayer chemisorption. Remarkably, the cl-CD@CA, presenting high selective adsorption toward cationic rather than anionic dyes, was potential for mixed dye separation. Moreover, the cl-CD@CA maintained excellent recyclability after 10 regeneration cycles. Excitingly, cl-CD@CA exhibited high static and dynamic adsorption capacity for actual dyeing wastewater, with a 79.3 % reduction in COD and 95 %, 29 % and 16 % concentration reduction of Pb2+, Cd2+ and Sb3+. Therefore, the newly developed lost-cost yet high-efficiency cl-CD@CA can serve as promising adsorbents to alleviate the water pollution caused by dyeing wastewater.