Synthesis and characterization of Pd⁰ nanoparticles supported over hydroxyapatite nanospheres for potential...

Nitrophenols, which are defined as an important toxic and carcinogenic pollutant in agricultural and industrial wastewater due to their solubility in water, form of resistance against all organisms in water resources. It is vital that these compounds, which are highly toxic as well as highly explosive, are removed from the aquatic ecosystem. In this paper, we reported the preparation and advanced characterization of Pd⁰ nanoparticles supported over hydroxyapatite nanospheres (Pd⁰@nano-HAp). The catalytic efficiency of the Pd⁰@nano-HAp catalyst was examined in the reduction of nitrophenols in water in the presence of NaBH₄ as reducing agent and the great activity of catalyst have been specified against 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol and 2,4,6-trinitrophenol compounds with 70.6, 82.4, 27.6 and 41.4 min^-1 TOF values, respectively. Another important point is that the Pd⁰@nano-HAp catalyst has perfect reusability performance (at 5th reuse between 68.5 and 92.8 %) for the reduction of nitrophenols. In addition, catalytic studies were carried out at different temperatures in order to determine thermodynamic parameters such as E, ΔH and ΔS.