Porous, pH-Responsive, and Reusable Hydrogel Beads of Bovine Serum Albumin_Au Hybrid as Smart Nanofactories for the Removal of Organic and Inorganic Pollutants from Water: A Detailed Demonstration by Spectroscopy and Microscopy.

The availability of potable water is one of the major concerns in many countries today. This brings in a need to design molecular scaffolds suitable for efficient adsorption of the contaminants present in water. In this paper, an unprecedented strategy is demonstrated in order to synthesize highly porous bovine serum albumin_Au (BSA_Au) beads and was employed for the removal of water contaminants. The beads stored in acidic medium (Beada) and in basic medium (Beadb) selectively adsorb anionic and cationic species that includes organic dyes and inorganic species, respectively, by showing a pH-responsive behavior. This phenomenon bestowed the beads with the recyclability and reusability as demonstrated for eight cycles wherein almost 100% efficiency is retained by the beads without any deterioration. The porous nature of these beads is retained even after switching the pH for several cycles of adsorption-desorption processes as judged based by the SEM data. Thus, the reported beads are demonstrated for their selective and efficient removal of both organic and inorganic contaminants from water wherein the beads can be recycled by triggering pH changes that would also release the captured species. The biologically benign beads act as reusable smart nanofactories in the purification of water from industrial contaminants.