A low-cost and efficient filter medium for Cd(Ⅱ) removal was prepared by anchoring-SCN functional groups(by 3-thiocyanatopropyltriethoxysilane, TCPS) on ceramsite via the approach of synthesizing a honeycomb calciuma...A low-cost and efficient filter medium for Cd(Ⅱ) removal was prepared by anchoring-SCN functional groups(by 3-thiocyanatopropyltriethoxysilane, TCPS) on ceramsite via the approach of synthesizing a honeycomb calciumaluminum-silicate-hydrate(C-A-S-H) layer as intermediate. The specific surface area of ceramsite was increased enormously by more than 50 times because of the modification of honeycomb layer. Moreover, the abundant Si-OH bonds existing in the structure of CAS-H can serve as active sites for TCPS. The combined effects ensure that the hybrid filter medium(named ceramsite/C-A-S-H/TCPS) demonstrated a high Cd(Ⅱ) adsorption capacity of 18.27 mg·g^-1 for particle size of 0.1-0.6 mm, 12.63 mg·g^-1 for 0.6-1.25 mm and 8.64 mg·g^-1 for 1.25-2.35 mm. The Cd(Ⅱ) adsorption capacity per unit area of ceramsite/C-A-S-H/TCPS(0.1-0.6 mm) is up to 4.07 mg·m^-2, which is much higher than that of many nano-adsorbents. In addition, ceramsite/C-AS-H/TCPS could maintain a high removal efficiency(> 85%) in a wide range of p H 3-11 and showed excellent selectivity in the presence of competing ions. Furthermore, Cd(Ⅱ) could be desorbed from ceramsite/C-A-S-H/TCPS composites with nearly 100%, suggesting the potential application in recycling of heavy metal ions.展开更多
基金Funded by the China National Key R&D Program(No.2018YFE0106300)the Fundamental Research Funds for the Central Universities(No.WUT:2019IB003)National Natural Science Foundation of China(No.51579159).
文摘A low-cost and efficient filter medium for Cd(Ⅱ) removal was prepared by anchoring-SCN functional groups(by 3-thiocyanatopropyltriethoxysilane, TCPS) on ceramsite via the approach of synthesizing a honeycomb calciumaluminum-silicate-hydrate(C-A-S-H) layer as intermediate. The specific surface area of ceramsite was increased enormously by more than 50 times because of the modification of honeycomb layer. Moreover, the abundant Si-OH bonds existing in the structure of CAS-H can serve as active sites for TCPS. The combined effects ensure that the hybrid filter medium(named ceramsite/C-A-S-H/TCPS) demonstrated a high Cd(Ⅱ) adsorption capacity of 18.27 mg·g^-1 for particle size of 0.1-0.6 mm, 12.63 mg·g^-1 for 0.6-1.25 mm and 8.64 mg·g^-1 for 1.25-2.35 mm. The Cd(Ⅱ) adsorption capacity per unit area of ceramsite/C-A-S-H/TCPS(0.1-0.6 mm) is up to 4.07 mg·m^-2, which is much higher than that of many nano-adsorbents. In addition, ceramsite/C-AS-H/TCPS could maintain a high removal efficiency(> 85%) in a wide range of p H 3-11 and showed excellent selectivity in the presence of competing ions. Furthermore, Cd(Ⅱ) could be desorbed from ceramsite/C-A-S-H/TCPS composites with nearly 100%, suggesting the potential application in recycling of heavy metal ions.
