Effects of pH on dechlorination of trichloroethylene by zero-valent iron

Effects of solvent, pH, salts and resin fatty acids on the dechlorination of pentachlorophenol using magnesium–silver and magnesium–palladium bimetallic systems

“…It may be also noted from Table 1 that substantial sorption of PCP (∼2 mg L −1 ) on the residual solid surfaces was observed for experiments conducted at pH value of 6.0 while almost complete dissolution of magnesium was observed at the end of 45 min of reaction conducted at pH 4.0. Linear increase in the reaction rate constant with decrease in reaction pH has been also reported for the dechlorination of carbon tetrachloride, atrazine, and trichloroethylene using Fe 0 by Matheson and Tratnyek [20], Dombek et al [21], and Chen et al [22], respectively. Based on the results presented in Table 1, the optimum pH for PCP dechlorination by Mg/Pd system may be considered to be ∼5.5 which required nominal dosing (70 mM) of acid.…”

“…It may be seen from Table 1 that there was marginal increase in the estimated initial reaction rate (dC PCP /dt) with the decrease in pH of the reaction medium. This result may be explained on the basis of increased corrosion of Mg 0 and reduced passivation of the metal at lower pH values [22]. It may be also noted from Table 1 that substantial sorption of PCP (∼2 mg L −1 ) on the residual solid surfaces was observed for experiments conducted at pH value of 6.0 while almost complete dissolution of magnesium was observed at the end of 45 min of reaction conducted at pH 4.0.…”

“…However most of the studies on dechlorination by bimetallic or zero-valent metal systems have been carried out using pure solutions of chlorinated organic pollutants. Very sparse literature related to the effects of reaction phase pH [15,[20][21][22], type of organic co-solvent [23][24][25] and impurities (co-pollutants) other than the target compound is available. Studies on the effect(s) of various environmental parameters as listed above are relevant for assessing the applicability of bimetallic systems for remediation of groundwater or raw industrial effluents containing chlorinated organic compounds.…”

Effect of pH on DDT degradation in aqueous solution using bimetallic Ni/Fe nanoparticles

“…Chen's study verified the kinetic model for the dechlorination reaction by using bimetallic Ni/Fe is a pseudo first-order treatment of the parent compound [13]:…”

“…Meanwhile, the ferrous and hydroxyl ions form ferrous hydroxide and precipitate. The surface passivating layer of the ferrous hydroxide and precipitate could hinder the transport of the chlorinated molecules and block the reactive sites on Ni/Fe and hence depress the overall reaction rate [13].…”