Preparation of core–shell structured CaCO 3 microspheres as rapid and recyclable adsorbent for anionic dyes

Core–shell structured CaCO 3 microspheres (MSs) were prepared by a facile, one-pot method at room temperature. The adsorbent dosage and adsorption time of the obtained CaCO 3 MSs were investigated. The results suggest that these CaCO 3 MSs can rapidly and efficiently remove 99–100% of anionic dyes within the first 2 min. The obtained CaCO 3 MSs have a high Brunauer–Emmett–Teller surface area (211.77 m 2  g −1 ). In addition, the maximum adsorption capacity of the obtained CaCO 3 MSs towards Congo red was 99.6 mg g −1 . We also found that the core–shell structured CaCO 3 MSs have a high recycling capability for removing dyes from water. Our results demonstrate that the prepared core–shell structured CaCO 3 MSs can be used as an ideal, rapid, efficient and recyclable adsorbent to remove dyes from aqueous solution.