Effect of mixing on reductive dechlorination of persistent organic pollutants by Fe/Pd nanoparticles

Abstract

Herein, we report the comparison of two different mixing methods for reductive dechlorination of gamma‐hexachlorocyclohexane (γ‐HCH), aldrin, and p, p’‐dichlorodiphenyl‐trichloroethane (p, p’‐DDT), using iron/palladium (Fe/Pd) bimetallic nanoparticles. A noticeable enhancement of the reaction rate was found when the reductive dechlorination reaction was carried out in an ultrasound bath as compared with a platform shaker. These enhancements could be attributed to (a) the continuous cleaning and chemical activation of the surfaces of nanoscale Fe/Pd bimetallic nanoparticles by the combined chemical and physical effects of acoustic cavitation; and (b) the accelerated mass transport rates of target POPs to the surfaces of the Fe/Pd nanoparticles. Finally, the degradation intermediates and final products were determined by gas chromatography/mass spectrometry (GC/MS) analysis and the plausible degradation pathways for γ‐HCH, aldrin, and p, p’‐DDT by Fe/Pd bimetallic nanoparticles were proposed. Practitioner points Exposure to POPs is a resilient global environmental and health issue. Fe/Pd bimetallic nanoparticles demonstrated > 90 % removal of POPs in the first 30 minutes of the reaction via ultrasonic mixing. GC‐MS analyses provided verification of POPs degradation intermediates and final products.

Removal of AOX in Activated Sludge of Industrial Chemical Dyestuff with Bimetallic Pd/Fe Particles

“…The reductive dehalogenation of some bimetallic materials can be an effective method for detoxifying halogenated organic compounds and has started to be widely investigated by some researchers [10][11][12][13][14][15]. In these bimetallic materials, the first metal, which has a low standard redox potential (such as Fe, Mg, etc.…”

“…In these bimetallic materials, the first metal, which has a low standard redox potential (such as Fe, Mg, etc. ), is an electron donor that reduces the halogenated organic compounds [11,13]; the second metal, which has a high standard redox potential (such as Ni, Cu, Pd, etc. ), promotes the reactivity via hydrogenation and acceleration corrosion [10][11][12]16], acting as both catalyst and accelerator.…”