Rapid and efficient removal of Cd(II) from aqueous solution in a wide range pH by sodalite type sorbents using cellulose superfine fiber as a template agent

Sodalite is a common zeolite , which is often discarded or ignored due to its small pore size and poor adsorption capacity. In this study, two sodalite type materials , CSF-S and N-CSF-S, were synthesized using cellulose superfine fiber (CSF) as template. Its unique scaly structure not only enhances its adsorption capacity for Cd (II), but also improves its adsorption efficiency. At 298 K and the initial Cd (II) concentration of 100 mg/L, the adsorption equilibrium of CSF-S was achieved within 30 min, which is 98% shorter than that of traditional sodalite. The adsorption of Cd (II) by CSF-S and N-CSF-S is an endothermic process and at 298 K the adsorption capacity could be as high as 260.1 and 284.1 mg/L, respectively, which were 1.9 and 2.0 times of the original sodalite, far higher than the reported similar adsorbents, and competitive to over other types of adsorbents. In addition, with low zero points of charge CSF-S (pH zpc around 1) and N-CSF-S (pH zpc around 3) can effectively remove Cd(II) over a wide pH range, superior to most zeolitic sorbent materials. Therefore, this work proposes a simple and cost-effective synthesis method for the sodalite type sorbents with high Cd(II) adsorption capacity and rapid adsorption rate, and also provides some basis for the study of heavy metal adsorption materials in aqueous systems.