Research Article

Design and Synthesis of Reusable Nanoparticles for Reversible Chemisorption of Hexavalent Chromium Anions from Aqueous Media and Catalysis

Table 2

Catalytic bromination activities of LEuH-Cl, Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@PW10 catalysts.

EntryCatalystBET surface area (m3/g)Yield (%)Time (h)Rate (mmol·g−1s−1)

1LEuH-Cl57.302221.2210−7
2Fe3O47.322321.2810−7
3Fe3O4@SiO213.572121.1710−7
4Fe3O4@SiO2@LEuH@PW1016.62990.15.510−3

Reaction conditions are as follows: 10 ml of 1.0 mM phenol red in water + 10 ml of 10.0 mM NH4Br in water + 0.5 g of catalyst + 2.5 mM·H2O2, in a round-bottomed flask. Time = 10 minutes, T = 298 K, and  atm. Rate of conversion = mole Br oxidized per total weight of catalyst (g) per second. Symbol “” denotes a multiplication sign.