Adsorption of lead (Pb-II) using CaO-NPs synthesized by solgel process from hen eggshell: Response surface methodology for modeling, optimization and kinetic studies

Venus antiqua Clamshell-Derived Calcium Oxide Nanoparticles for the Preparation of PLA/d-Limonene/CaO Nanocomposites with Antimicrobial Properties

“…The absorption peak at 3640 cm –1 corresponds to the O–H bond, indicating the presence of water molecules on the nanoparticle surface. , The peaks at 1409, 1064, and 870 cm –1 were assigned to the C–O bond, indicating calcium oxide nanoparticles’ carbonation. , As reported, the absence of intense absorption in the near region to 1450 cm –1 indicates that CaCO 3 was no longer present as it was already converted to CaO. , On the other hand, Figure B exhibits the crystalline structure of the nanoparticles. The XRD pattern CaO showed different diffraction peaks in the 10–80° range, which coincides with those reported by other authors. ,,,, The cubic structure of calcium oxide was related to the reflections at 32, 37, 54, 64, and 67°, which coincide with planes (111), (200), (220), (311), and (222), respectively. ,,,, Besides, the peak that appears at 79° is assigned to the plane (400) of the lime phase. The XRD pattern of CaO suggested that CaCO 3 in the raw clamshell was wholly transformed to calcium oxide during the synthesis process.…”

“…33,40,42,55,56 The cubic structure of calcium oxide was related to the reflections at 32, 37, 54, 64, and 67°, which coincide with planes ( 111), ( 200), ( 220), (311), and (222), respectively. 33,40,42,56,57 Besides, the peak that appears at 79°is assigned to the plane (400) of the lime phase. The XRD pattern of CaO suggested that CaCO 3 in the raw clamshell was wholly transformed to calcium oxide during the synthesis process.…”

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

“…Lower removal of heavy metal ions were noticed at acidic pH and higher removal efficiency observed at neutral. At lower pH, H 3 O + ions compete against Cr +6 and Pb +2 ions for binding and are surrounded by hydronium ions (H + ) stopping metal ions from approaching the binding sites and it leads to low adsorption capacities [78] . Positively charged metal ions and positively charged sites were incapable of binding metal ions due to electrostatic repulsion and low removal percentage of both heavy metal ions (Cr +6 and Pb +2 ) observed.…”

“…At lower pH, H 3 O + ions compete against Cr + 6 and Pb + 2 ions for binding and are surrounded by hydronium ions (H + ) stopping metal ions from approaching the binding sites and it leads to low adsorption capacities. [78] Positively charged metal ions and positively charged sites were incapable of binding metal ions due to electrostatic repulsion and low removal percentage of both heavy metal ions (Cr + 6 and Pb + 2 ) observed. There were fewer H + ions taking place in the solution when pH increased and as a result more negatively charged sites were made and higher metal ion removal was introduced by electrostatic attraction.…”

Corncob-supported calcium oxide nanoparticles from hen eggshells for cadmium (Cd-II) removal from aqueous solutions; Synthesis and characterization

“…Calcium oxide (CaO) nanoparticles have shown promising results in this regard. However, the majority of these studies have utilized conventional precursors or commercially available sources for the synthesis of CaO nanoparticles [ [9] , [10] , [11] , [12] , [13] ]. This highlights an important research gap concerning the use of sustainable resources for CaO nanoparticle synthesis.…”