Oxidative-coupling reaction of TNT reduction products by manganese oxide

Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

“…Figure 9 shows the plot of lnC 0 /C against t where, C represents the concentration of MB at time, t, and C 0 represents the initial concentration of MB. The kinetics of the degradation process fitted to the pseudo-first-order kinetics model well which is in good agreement with the earlier works [12,13,42], where the authors reported the oxidative degradation of a number of organic pollutants with Mn oxides. In the present study, the rate constant (k) was found to be 0.0045 min −1 .…”

“…As manganese (Mn) oxides are powerful oxidants having high-reducing potential, for pollution remediation purpose, land-born natural Mn ores, synthetic nascent state Mn oxides, and materials coated/modified with Mn oxides have been tested as oxidants for degradation of organic pollutants [7,8]. It has already been reported that oxides and hydroxides of Mn 3+ and Mn 4+ can oxidize a variety of natural and xenobiotic organic compounds such as catechol, quinines, substituted phenols, aromatic amines, pesticides, and explosives (e.g., TNT) [9][10][11][12][13]. Trimanganese tetraoxide (Mn 3 O 4 ) is a mixed oxide of Mn containing both di-and tri-valents of Mn.…”

Oxidative decolorization of methylene blue using pelagite

“…0.6 g L −1 ) pelagite, unless otherwise stated, was added into a flask reactor containing 500 mL MB solution (concentrations and pH ranging from 10 to 100 mg L −1 and from 3.0 to 10.0, respectively). System pH as the reactions proceeded was not controlled, since inorganic ionic compounds added for pH adjustment or buffering may adsorb on surface of the pelagite and organic buffer agents used may be oxidized, which would substantially affect MB degradation [11]. At specific time intervals (10 min-1 h) aliquots of 10-mL suspension were sampled using a syringe and filtrated through a 0.22-m syringe-end filter.…”

“…Several authors reported that, in pH-buffered system, the kinetics of oxidative degradation of a number of organic pollutants by Mn oxides was first-order with respect to organic pollutant concentration over the initial stage, but deviated from the pseudofirst-order equation as the reaction prolonged [10,35]. Without pH control as reaction proceeded, Kang et al [11] also found oxidative degradation of 2,4,6-trinitrotoluene (TNT) by birnessite (␦-MnO 2 ) well followed the pseudofirst-order kinetics with respect to birnessite loading over the initial stage. Among many studies above, suspension pH was found to exert a marked influence on the overall kinetic rate for oxidative degradation of a series of organic pollutants.…”

“…It is recognized that Mn oxides can oxidize many inorganic compounds including Co(II) [2], Cr(III) [3], As(III) [4], Sb(III) [5], and Se(IV) [6], and a wide spectrum of natural and xenobiotic organic compounds such as catechol, quinines, substituted phenols, aromatic amines, pesticides, and explosives (e.g. TNT) [7][8][9][10][11]. It has been reported that abiotic degradation of a numlower than that of land-born Mn ores.…”