Chitosan-Based Silver Nanocomposite for Hexavalent-Chromium Removal from Tannery Industry Effluent Using a Packed-Bed Reactor

Chitosan-based silver nanocomposite beads were synthesized through the facile chemical precipitation method, and its efficiency was evaluated for removal of hexavalent chromium from synthetic and tannery industrial effluents in a packed bed reactor. The developed silver nanocomposite has been characterized through Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis. The effect of various process parameters, such as residence time (3–7 h), initial Cr (VI) concentration (10–30 ppm), silver nanocomposite dosage (5–30  g/L), and flow rate (5–20  mL/min), was investigated using synthetic effluent. Silver nanocomposite has the BET surface area and porosity of 0.710  m²/g and 88%, respectively. Maximum Cr (VI) removal was achieved with a residence time of 5 h, initial Cr (VI) concentration of 20 ppm, silver nanocomposite dosage of 30  g/L, and flow rate of 5  mL/min. The results exhibited that an increase in initial chromium concentration, the amount of bead, and residence time increased the efficiency of chromium removal, whereas an increase in the flow rate decreased sorption efficiency. Further, the evaluated process parameters exhibited almost 90% of Cr (VI) elimination from tannery industrial effluent [initial Cr (VI) concentration of 20 ppm] in a packed bed reactor. The study revealed that synthesized silver nanocomposite could be used as a potential sorbent for hexavalent chromium removal from synthetic and industrial effluents. © 2020 American Society of Civil Engineers