Rapid Degradation of Carbon Tetrachloride by Microscale Ag/Fe Bimetallic Particles

Abstract

Cost-effective zero valent iron (ZVI)-based bimetallic particles are a novel and promising technology for contaminant removal. The objective of this study was to evaluate the effectiveness of CCl4 removal from aqueous solution using microscale Ag/Fe bimetallic particles which were prepared by depositing Ag on millimeter-scale sponge ZVI particles. Kinetics of CCl4 degradation, the effect of Ag loading, the Ag/Fe dosage, initial solution pH, and humic acid on degradation efficiency were investigated. Ag deposited on ZVI promoted the CCl4 degradation efficiency and rate. The CCl4 degradation resulted from the indirect catalytic reduction of absorbed atomic hydrogen and the direct reduction on the ZVI surface. The CCl4 degradation by Ag/Fe particles was divided into slow reaction stage and accelerated reaction stage, and both stages were in accordance with the pseudo-first-order reaction kinetics. The degradation rate of CCl4 in the accelerated reaction stage was 2.29–5.57-fold faster than that in the slow reaction stage. The maximum degradation efficiency was obtained for 0.2 wt.% Ag loading. The degradation efficiency increased with increasing Ag/Fe dosage. The optimal pH for CCl4 degradation by Ag/Fe was about 6. The presence of humic acid had an adverse effect on CCl4 removal.

Removal of Trichloroethylene from Water by Bimetallic Ni/Fe Nanoparticles

“…As shown in Table 1, the degradation reactions of ZVI in halogenated hydrocarbons were all fitted with pseudo-first-order reaction kinetics [33,34]. The value of K obs in the kinetic equation represents the apparent degradation rate; the higher the value of K obs , the higher the degradation efficiency.…”

Interactions between nanoscale zerovalent iron (NZVI) and silver nanoparticles alter the NZVI reactivity in aqueous environments

“…A recent study reported that AgNP morphology may change from a dispersed 18 spherical shape to larger aggregates owing to the release of Ag + possibly because of (i) the nano bridges created by adsorption and/or redox conversion of Ag + into Ag 0 at the particle surface to connect nearby particles, and (ii) the growth of reformed small AgNPs around old AgNPs (Yu et al, 2014). Other reports showed that Ag + released from AgNPs and possible electron transfer from Fe 0 to Ag + could form a galvanic couple, which may accelerate NZVI-water corrosion (Zhuang et al, 2011;Zhu et al, 2021). Therefore, interactions of Ag + ions (E0 Ag/Ag + 0.799 V) with NZVI (E0 Fe/Fe 2+ 0.44 V) and AgNPs through adsorption and/or electron transfer processes may alter the particle aggregation behavior and surface reactivity.…”

Efficient Reduction of Carbon Tetrachloride in an Electrochemical Reactor with a Three-Dimensional Electrode

“…Numerous studies have addressed different routes for the disposal of carbon tetrachloride by multiple means, which are not only chemical but also physical, such as pyrolysis [5][6][7][8][9]. However, its disposal through recycling it into a useful product for the chemical industry has hardly been addressed.…”