Fabrication of Sodium Alginate Porous Scaffolds for Heavy Metal Ion Removal from Aqueous Solution

Abstract

The adsorption method is recognized as an effective technology for dealing with water pollution caused by heavy metal ions. For a highly efficient, eco-friendly and low-cost adsorption process, the adsorbent is the deciding factor. In this study a porous sodium alginate scaffold was prepared by the method of freeze-drying as a heavy metal ion adsorbent. The parameters affecting the morphology and adsorption characteristics of the scaffolds were investigated. The results showed that sodium alginate porous scaffolds could be prepared under the concentration in the range of 1–5%. After calcium ion pre-crosslinking, the sodium alginate scaffold was used to adsorb the heavy metal ions of Cd²⁺, Pb²⁺, and Cu²⁺ from aqueous solution and the maximum adsorption efficiency under optimized adsorption conditions were 99.43%, 73.67%, and 59.25%, respectively. At the same time, the scaffold could be used for desorption and recycling. After five cycles, the removal percentages of Pb²⁺, Cd²⁺, and Cu²⁺ by the sodium alginate scaffold decreased by 25%, 25%, and 16%, respectively.

Keywords:

• heavy metal ions removal
• porous scaffolds
• sodium alginate
• water pollution

Acknowledgements

This research was supported by the Longyan Science and Technology Project fund (Grant No. 2019LYF7006) and the Fujian Provincial Natural Science Foundation of China (Grant No. 2019J01847).