Catalytic hydrodechlorination of 2,4-dichlorophenol over nanoscale Pd/Fe: Reaction pathway and some experimental parameters

An integrated two-stage process for effective dechlorination of polychlorinated biphenyls in subcritical water in the presence of hydrogen donors

“…In weak acidic water, the amount of H + is sufficient to produce hydrogen species via corrosion of Fe 0 but not enough to cause the break of electronic contact between Fe 0 and Ni o as shown in Fig. 1b, which was also observed by Bokare et al [10,11]. Meantime, lower pH caused by the addition of organic acid could prevent formation of passivation layer to a certain extent in ambient water [13].…”

“…Acids, regardless of whether it is organic or inorganic, not only play the role of reaction enhancer by supplying H + for generation of hydrogen species but also act as reaction retarder in point of causing the corrosive dislodgment of catalyst from bimetallic particles [11,28]. The results in Fig.…”

“…2b and c show that the Ni percentage at the outer layer of particles after reaction decreased with increase of amount of organic acid used as compared to that without hydrogen donor. This suggests that partial dislodgement of Ni from bimetallic Ni/Fe might occur due to the dissolution of Fe into liquid phase especially in the presence of organic acid [10,11], which could impair the catalytic function of Ni/Fe particles. Fig.…”

“…Studies have aimed at enhancing utility efficiency of Fe 0 by introduction hydrogen donors in order to increase available H + concentration, such as inorganic and organic acid [9][10][11][12][13]. Meanwhile, addition of acid can also retard the formation of passivation layers on particles surface because the precipitates of iron oxide is dependent on the pH of water in terms of mechanisms depicted as follows [6,10,13].…”

Kinetics of 2-chlorobiphenyl Reductive Dechlorination by Pd-fe0Nanoparticles

“…Pd-Fe 0 bimetallic nanoparticles have been improved to completely dechlorinate chloroaromatics and thoroughly purify a wide range of chlorinated organic compounds without leaving chlorinated side products [2][3][4][5][6]. As one of the noble metal, Pd can utilize the produced H 2 from zero-valent iron (ZVI) corrosion and improve the rates and efficiencies of dechlorination reaction [1,4].…”