Dechlorination of p-chlorophenol from aqueous solution using bentonite supported Fe/Pd nanoparticles: Synthesis, characterization and kinetics

• Published in: Desalination Vol. 280; no. 1; pp. 167 - 173
• Main Authors: Su, Jin, Lin, Shen, Chen, Zuliang, Megharaj, Mallavarapu, Naidu, Ravendra
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 03-10-2011; Elsevier
• Subjects: activation energy; Applied sciences; Bentonite; Catalysis; Catalytic reactions; Characterization; Chemical engineering; Chemistry; Dechlorination; desalination; Exact sciences and technology; Fe/Pd nanoparticles; General and physical chemistry; hydrogen; Iron; Kinetics; Nanoparticles; Palladium; Pollution; Reaction kinetics; Reactors; scanning electron microscopes; Scanning electron microscopy; surface area; temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; X-radiation; X-ray diffraction; X-rays; Characterization; Bentonite; Dechlorination; Kinetics; Fe/Pd nanoparticles; Scanning electron microscopy; Nanoparticle; Specific surface area; Dispersive spectrometry; X ray diffraction; Dispersion; Aggregation; Loading; First order; Aqueous solution; Thermodynamic properties; Chemical reactivity; Activation energy; Catalyst
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2011.06.067

To increase the dispersion of nanoparticles and enhance their reactivity, bentonite-supported Fe/Pd nanoparticles (B/Fe/Pd) were synthesized and used for the dechlorination of P-chlorophenol (p-CP) from aqueous solution. The B/Fe/Pd was characterized with a scanning electron microscope (SEM), X-ray energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), and specific surface area (BET). The results showed that the presence of bentonite led to a decrease in aggregation of Fe/Pd nanoparticles and enhanced their reactivity. More specifically, B/Fe/Pd indicated the highest p-CP dechlorination of 100%, while only 25.0% and 15.0% were obtained using B/Fe and bentonite (the conditions: C
0
=
5.0
mg/L and dose: 10.0
g/L), respectively. In addition, kinetic studies show that the dechlorination rate of p-CP was described by pseudo first-order reaction kinetics, and the dechlorination rate increased with rising temperature and Pd loading. The apparent activation energy for dechlorination p-CP using B/Fe/Pd was 40.1
kJ/mol, which is characteristic of a chemically surface-controlled reaction. Finally, a potential mechanism for degradation of p-CP is proposed, which is based on Fe acting as the reducing agent, while Pd acts as a catalyst with hydrogen generated from water and bentonite as a support.
Comparison of p-CP removal using various materials.
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► Bentonite-supported Fe/Pd (B/Fe/Pd) nanoparticles for the removal of P-chlorophenol. ► p-CP dechlorination efficiency of 100% was obtained. ► Characterizations of B/Fe/Pd were by SEM, EDS and XRD. ► A mechanism for degradation of p-CP was proposed.