Polymeric nanofibers for the removal of Cr(III) from tannery waste water

• Cysteine-modified polymeric nanofibers were fabricated.
• The modified nanofibers were used to remove Cr(III) from tannery waste water.
• The optimized removal capacity was 1.75 g of Cr(III)/g of polymeric material.
• The removal capacity is far greater than previously reported materials.

We demonstrate the use of cysteine-modified polymer nanofibers for the rapid and efficient removal of Cr(III) from real tannery waste water samples. Various parameters such as pH, load of nanofibers and time of exposure were optimized to achieve maximum removal. The optimum parameters were found to be 0.1 mg of nanofibers per mL of tannery waste water with a pH of 5.5 and an exposure time of 45 min. Almost 99% Cr(III) was removed at these ideal conditions thus demonstrating the efficacy of our material. The maximum removal capacity at these ideal conditions was estimated to be approximately 1.75 g of chromium/gram of polymeric material. This is probably due to a variety of factors including the apparent high surface to volume ratio exhibited by these nanofibers and also due to the availability of numerous cysteine groups that are known to have high binding affinities with heavy metal ions. These nanoscale polymeric materials show great potential towards the removal of heavy metal cations from waste waters.