Degradation of tetrachloromethane and tetrachloroethene by Ni/Fe bimetallic nanoparticles

Abstract

Abstract.The study investigated the potential of nanoscale Ni/Fe bimetallic particles reduction for carbon tetrachloride (CT) and tetrachloroethene (PCE). BET specific surface areas of the laboratory synthesized Ni/Fe (2% wt.) particle, with diameter on the order of 20-60nm, was approximately 52.61m 2 /g. Batch studies demonstrated that rapid transformations of PCE and CT were achieved with nanoscale Ni/Fe particles. The degradation process appeared to be pseudo-first-order. Values of the surface area normalized rate coefficients (K SA ) of PCE and CT for the reaction with nano Ni/Fe were 2.068mL/(m 2 ·h), 10.08mL/( m 2 ·h), respectively. This indicated that the degradation rate of CT was about 5 times larger than that of PCE under comparable environmental condition. Significant amounts of DCM were detected for the reaction with CT unlike the PCE transformation where ethane was the only end-product, amount to 103% of the initial PCE carbon. Both DCM (~15%) and methane (~27%) were the major end products for CT reaction. Based on the rapid rate of degradation and no or less chlorinated byproducts, the nanoscale particles technology offered great opportunities for both fundamental research and technological application for remediation of contaminated ground water.

Synthesis and Characterization of Zero-Valent Fe-Cu and Fe-Ni Bimetals for the Dehalogenation of Trichloroethylene Vapors

“…To improve ZVI reactivity, transition metals with a redox potential higher than iron have been used as catalysts for dechlorination through the enhancement of iron corrosion or hydrogenation [2,5,12,14]. Among transition metals, the most studied as cata-lysts for the degradation of chlorinated compounds induced by iron were palladium (Pd) [2,3,[15][16][17][18][19], nickel (Ni) [2,15,17,18,[20][21][22][23][24][25][26], and copper (Cu) [2,5,12,15,17,18,20]. To a lower extent, ruthenium (Ru) [3], silver (Ag) [3,15,18], cobalt (Co) [17], zinc (Zn) [27,28], and platinum (Pt) [3,17] were also tested.…”

“…To a lower extent, ruthenium (Ru) [3], silver (Ag) [3,15,18], cobalt (Co) [17], zinc (Zn) [27,28], and platinum (Pt) [3,17] were also tested. In general, adding these metals to iron creates a galvanic cell [15,23]. In these conditions, greater corrosion of ZVI occurs with a consequent increase in the release of electrons necessary for the reduction of chlorinated contaminants [5,29].…”

“…In these conditions, greater corrosion of ZVI occurs with a consequent increase in the release of electrons necessary for the reduction of chlorinated contaminants [5,29]. Furthermore, several transition metals, such as Pd or Ni, are hydrogenation catalysts [2,18,26] able to catalyze the dissociation of molecular hydrogen generated by water reduction, and thus the release of atomic hydrogen, which is useful for dechlorination reactions [2,23,[29][30][31]. Moreover, the addition of a secondary transition metal to ZVI lowers the activation energy of the dehalogenation reaction, thus limiting the formation of oxide layers, which can reduce the electron transfer during the dechlorination process [2,23,32].…”

“…Furthermore, several transition metals, such as Pd or Ni, are hydrogenation catalysts [2,18,26] able to catalyze the dissociation of molecular hydrogen generated by water reduction, and thus the release of atomic hydrogen, which is useful for dechlorination reactions [2,23,[29][30][31]. Moreover, the addition of a secondary transition metal to ZVI lowers the activation energy of the dehalogenation reaction, thus limiting the formation of oxide layers, which can reduce the electron transfer during the dechlorination process [2,23,32]. Furthermore, with the addition of these metals, it is possible to increase the degradative capacity of ZVI toward various chlorinated recalcitrant compounds, such as polychlorinated biphenyls (PCBs) or pentachlorophenol (PCP) [12,16,33].…”

Synergistic Degradation of Methylene Blue By Novel Fe-Co Bimetallic Catalyst Supported On Waste Silica in Photo-Fenton-Like System

“…The FBC process can simultaneously remove Fe and Co and recover them as bimetallic Fe-Co catalyst [39][40][41]. Existing methods to synthesize bimetallic catalysts are only used for the sole purpose of catalyst preparation [42][43][44][45][46]. The major advantages of FBC over the existing synthesis techniques are the avoidance of sludge formation, material recovery, and reduction of solid wastes.…”