Industrially scalable Chitosan/Nylon-6 (CS/N) nanofiber-based reusable adsorbent for efficient removal of heavy metal from water

Industrially scalable fabrication of Chitosan (CS)/Nylon-6 (N) based nanofiber membrane was achieved using novel Solution Blowing technique with 40% Nylon-6 being replaced with Chitosan. The membrane was used as an efficient, reusable adsorbent of heavy metal (Cu2+) from water encompassing a wide range of metal ion concentrations, namely- 3-100 mg/L. At pH- 4 the adsorption was most favorable, and the maximum capacity was found to be as high as 240 mg/g owing to highly available active amine (-NH2) groups. At lower concentration, the adsorption profile could be matched with both Langmuir and Freundlich adsorption isotherms. However, both isotherms failed at higher concentration regime, hypothesizing possible access to sub-surface availability of active sites, which is otherwise not reported for fiber-based adsorbents as per best of knowledge of authors. Large scale (4L) demonstration with such adsorbent, with 90% metal ion removal efficiency, exhibits the potential of the membrane in practical applications. The membrane could be reused up to 8 times where the leachate can be used for metal extraction.

Automated summary

The study achieved the industrially scalable fabrication of a Chitosan/Nylon-6 based nanofiber membrane for efficient adsorption of heavy metal contaminants in water, demonstrating its potential in practical applications and the ability for multiple reuses.