Chicken Egg Shell Waste Derived Calcium Oxide Based Nanohybrid For Rapid Removal of Heavy Metal Ions from Water: Green Synthesis, Kinetics and Reusability

Abstract

AbstractThe carcinogenic metal ions chromium (Cr+6) and lead (Pb+2) are prominent water pollutants. To substantiate this, green synthesized SnO2 nanoparticle (using S. mukorossi extract) was coupled with egg shell derived CaO nanocrystals. Crystalline nature of synthesized catalyst confirmed by PXRD and microscopic study revealed spherical SnO2 decorated on the irregular surface of CaO. Synthesized nanohybrid followed adsorption and photocatalytic reduction (Cr+6 to Cr+3; Pb+2 to Pb0) (Cr+6: 94 %; Pb+2: 88 %) phenomenon. Synergism of CaO (51.9 m2 g−1; 2.9 eV) and SnO2 (13.3 m2 g−1; 3.15 eV) was resulted into plenty of surface area (91.9 m2 g−1), low band gap (2.4 eV), and semiconducting nature of nanohybrid. As compared to Pb+2 removal of Cr+6 was faster due to higher value of reduction potential [Cr+6/Cr+3 (1.35 eV); Pb+2/Pb0 (−0.1262 eV)]. Photocatalyst proved to be effective upto 10th cycle. SnO2@CaO nanohybrid might be considered a potential photocatalyst in industries with sustainable approach.