Adsorption of natural composite sandwich-like nanofibrous mats for heavy metals in aquatic environment.

Natural polymer cellulose acetate (CA) and natural rectorite (REC) were employed to fabricate nanofibrous mats and then immobilized with biosorbent saccharomyces cerevisiae (SCV) to construct a sandwich-like structure. The hydroxyl and carbonyl groups in the CA endowed the nanofibrous mats with a strong affinity for removing heavy metals, allowing them to act as an adsorbent for heavy metals. The REC, which was blended with CA to fabricate the CA/REC nanofibrous mats, increased the specific surface area of the nanofibers and provided ideal scaffolds for the attachment of SCV, resulting in more contact reactions between the nanofibrous mats and heavy metal ions. The adsorption equilibrium was reached within 30 min at the optimum pH of 7, and the saturated adsorption capacities of Zn (II) and Cd (II) were 104.31 and 99.33 mg/g, respectively. The adsorption for Zn (II) and Cd (II) decreased to 47.44 and 62.11 mg/g in the co-system, but the total amount of adsorption (111.36 mg/g) was remarkably higher than that for the single system, indicating that the all-natural composite mats had great potential to simultaneously adsorb multiple heavy metals. After three cycles adsorption-desorption, the composite mats maintained a high adsorption efficiency.