Oxidation of Binary DNAPL Mixtures Using Potassium Permanganate with a Phase Transfer Catalyst

Abstract

Phase transfer catalysts (PTCs) can enhance the oxidation of pure DNAPLs using potassium permanganate by facilitating reactions in the organic phase. This study examined the influence of pentyltriphenylphosphonium bromide (PTPP) as a PTC on the rate of permanganate (MnO4‐) oxidation of DNAPLs in pure phases and mixtures. Kinetic batch experiments with trichloroethylene (TCE), 1,1,2‐trichloroethane (TCA), tetrachloroethylene (PCE), 1,1,2,2‐tetrachloroethane (TECA), and their mixtures, (1:1, v/v) were performed in test tubes to assess reaction rates. The disappearance of MnO4‐ was quantified by capturing digital images pf the tubes. This rapid photographic monitoring approach was validated by comparison with an UV‐Vis spectrometer method. The PCE/TCA mixture was selected to examine the impact of relative contents of a component in the binary mixture on the MnO4‐ disappearance. The comparative rates of MnO4‐ consumption for pure phases were TCE > TECA > PCE > TCA. PTPP increased MnO4‐ consumption rates, especially for TCE and TECA as pure, phases. The consumption rates of mixtures without PTPP were lower than those including the pure phases. However, due to their high extraction capability for PTPP‐MnO4‐ ion pairs, TCA and TECA appeared to increase the MnO4‐ consumption significantly when they were mixed with TCE or PCE, The increase in consumption rates with PTPP was most remarkable with the mixture of PCE and TCA. Chloride concentration showed faster increases for the mixtures with relative PCE contents ranging about 5 % to 90%, maximum at about 50% PCE, than for pure phases of PCE and TCA when the PTC assisted the reactions. The PTC appears to be promising in its ability to increase oxidation rates of DNAPL mixtures.

Carbon Isotope Fractionation during Permanganate Oxidation of Chlorinated Ethylenes (cDCE, TCE, PCE)

“…Hence, significant attention has been devoted to the investigation of the efficacy of various biological and abiological remediation processes which may accelerate the degradation of chlorinated ethylenes. In particular, remediation of chlorinated ethylenes by oxidation using permanganate has recently been the subject of numerous studies because of the following: oxidation with permanganate is rapid and results in essentially complete mineralization to produce environmentally benign compounds (CO 2 , chloride); permanganate is not scavenged by carbonate or bicarbonate as may be the case with other oxidants; permanganate has a high aqueous solubility in contrast to some other oxidants; permanganate has a long history of use for treatment of drinking water; and remediation using permanganate may be implemented at relatively low cost ( − ).…”

Improving the treatment of non-aqueous phase TCE in low permeability zones with permanganate

“…The use of phase-transfer catalyst in an environmental context has only been sparingly studied. Seol and Schwartz [32] and Seol et al [33] found that PTPP paired with MnO 4 − increased the dechlorination rate of TCE and PCE. Experiments by Seol and Schwartz [32] were confined to 60 min batch reactions where Cl − released and MnO 4 − consumed were measured and used to corroborate an improved rate of TCE removal.…”

“…The idea for using phase-transfer catalysts would be to allow some of the oxidant (i.e., MnO 4 − ) to partition into the non-aqueous phase DNAPL so that oxidation can occur in both the organic and bulk aqueous phases and reduce the time needed to remove the non-aqueous phase product. Seol and Schwartz [32] and Seol et al [33] used the phase transfer catalyst, pentyltriphenylphosphonium bromide (PTPP) in bench studies and reported increased dechlorination of both TCE and PCE. Although the initial results were promising, reports of using phase-transfer catalysts under transport conditions have not yet been reported.…”

Exploitation of KMnO4material as precursors for the fabrication of manganese oxide nanomaterials

“…Since its discovery in 1659, potassium permanganate has a long history of application to different fields, such as catalysis, medicine and electrochemical and mechanical areas [12]. It is used as an oxidant in drinking water, wastewater and industrial processes [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. The use of potassium permanganate in the synthesis area was achieved to prepare many manganese oxide nanostructures [29][30][31][32][33][34][35][36][37][38][39][40][41].…”