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Dionysios D Dionysiou - One of the best experts on this subject based on the ideXlab platform.

  • chemical and microbial decontamination of pool water using activated Potassium Peroxymonosulfate
    Water Research, 2008
    Co-Authors: George P Anipsitakis, Thomas P Tufano, Dionysios D Dionysiou
    Abstract:

    Potassium Peroxymonosulfate activation leads to the formation of highly reactive species, mainly the sulfate radicals. Activated Potassium Peroxymonosulfate (from now on Peroxymonosulfate) was tested against specific pollutants such as ammonium ion, creatinine, chlorinated creatinine products, arginine and Escherichia coli (E. coli), all constituents or derivatives of human discharges. The objective was to assess whether activated Peroxymonosulfate can be a viable treatment reagent in recreational water applications. It was found that organic molecules such as creatinine, chlorinated creatinine products and arginine could be effectively treated with activated Peroxymonosulfate. Ammonium ion was oxidized only by chlorine species and only in de-ionized water. Chlorine species were formed from the reaction of sulfate radicals with chloride ions. In pool water, the reaction of sulfate radicals with chloride ions and the subsequent ammonium ion oxidation were scavenged by the presence of bicarbonate ions. The Co/Peroxymonosulfate system was also shown to be an effective disinfection reagent, since 99.99% (4-log) kill of E. coli was achieved in 60 min of treatment. At the concentrations tested here, however, it is still not efficacious enough to qualify as an EPA-registered sanitizer for swimming pools (requires 6-log kill of E. coli, ATCC 11229, and Enterococcus faecium, ATCC 6569, in 30s).

  • chemical and microbial decontamination of pool water using activated Potassium Peroxymonosulfate
    Water Research, 2008
    Co-Authors: George P Anipsitakis, Thomas P Tufano, Dionysios D Dionysiou
    Abstract:

    Abstract Potassium Peroxymonosulfate activation leads to the formation of highly reactive species, mainly the sulfate radicals. Activated Potassium Peroxymonosulfate (from now on Peroxymonosulfate) was tested against specific pollutants such as ammonium ion, creatinine, chlorinated creatinine products, arginine and Escherichia coli ( E. coli ), all constituents or derivatives of human discharges. The objective was to assess whether activated Peroxymonosulfate can be a viable treatment reagent in recreational water applications. It was found that organic molecules such as creatinine, chlorinated creatinine products and arginine could be effectively treated with activated Peroxymonosulfate. Ammonium ion was oxidized only by chlorine species and only in de-ionized water. Chlorine species were formed from the reaction of sulfate radicals with chloride ions. In pool water, the reaction of sulfate radicals with chloride ions and the subsequent ammonium ion oxidation were scavenged by the presence of bicarbonate ions. The Co/Peroxymonosulfate system was also shown to be an effective disinfection reagent, since 99.99% (4-log) kill of E. coli was achieved in 60 min of treatment. At the concentrations tested here, however, it is still not efficacious enough to qualify as an EPA-registered sanitizer for swimming pools (requires 6-log kill of E. coli , ATCC 11229, and Enterococcus faecium , ATCC 6569, in 30 s).

  • transition metal uv based advanced oxidation technologies for water decontamination
    Applied Catalysis B-environmental, 2004
    Co-Authors: George P Anipsitakis, Dionysios D Dionysiou
    Abstract:

    Abstract This study explores the effect of ultraviolet (UV) light radiation and/or transition metals (M) for the activation of common oxidants (Ox) with the objective of treating recalcitrant organic contaminants in water. Hydrogen peroxide, Potassium Peroxymonosulfate and Potassium persulfate were combined with iron, cobalt and silver, respectively, and/or with UV light (254 nm) and were tested for the treatment of 2,4-dichlorophenol (2,4-DCP). Results from our previous studies indicated that these particular transition metals are the best catalysts for the activation of the respective oxidants [G.P. Anipsitakis, D.D. Dionysiou, Environ. Sci. Technol. 37 (2003) 4790; G.P. Anipsitakis, D.D. Dionysiou, Environ. Sci. Technol. 38 (2004) 3705]. From the combined use of UV, the oxidants and the transition metals, four general categories of advanced oxidation technologies were evaluated and compared for the degradation and mineralization of 2,4-DCP. Those were (i) the dark conjunction of each oxidant with its favorable metal activator (M/Ox), (ii) the use of UV alone, (iii) the combination of UV with each oxidant (UV/Ox) and (iv) the use of UV combined with each metal/oxidant systems (UV/M/Ox). In particular, the systems UV/KHSO5, UV/Co(II)/KHSO5 and UV/Ag(I)/K2S2O8 and the sulfate radicals generated thereby have never been tested before for water decontamination, as opposed to the extensively investigated hydroxyl radicals generated by UV/H2O2 and the photo-Fenton. The comparison of the results with respect to the transformation of 2,4-DCP and the extent of organic carbon removal led to the construction of the following order of efficiencies: UV/K2S2O8 > UV/KHSO5 > UV/H2O2 for the UV/Ox processes and UV/Fe(III)/H2O2 > UV/Fe(II)/H2O2 > UV/Co(II)/KHSO5 > UV/Ag(I)/K2S2O8 for the UV/M/Ox processes tested here. All experiments were homogeneous and conducted at ambient room temperature. The relative absorbance of the species participating in the reactions supports the former order of efficiency, since persulfate followed by Peroxymonosulfate were proven more photosensitive than hydrogen peroxide. Among the metals tested, only iron species such as Fe(OH)2+ were found to absorb strongly at 254 nm and to this is attributed the higher efficiencies obtained with the photo-Fenton reagents.

George P Anipsitakis - One of the best experts on this subject based on the ideXlab platform.

  • chemical and microbial decontamination of pool water using activated Potassium Peroxymonosulfate
    Water Research, 2008
    Co-Authors: George P Anipsitakis, Thomas P Tufano, Dionysios D Dionysiou
    Abstract:

    Potassium Peroxymonosulfate activation leads to the formation of highly reactive species, mainly the sulfate radicals. Activated Potassium Peroxymonosulfate (from now on Peroxymonosulfate) was tested against specific pollutants such as ammonium ion, creatinine, chlorinated creatinine products, arginine and Escherichia coli (E. coli), all constituents or derivatives of human discharges. The objective was to assess whether activated Peroxymonosulfate can be a viable treatment reagent in recreational water applications. It was found that organic molecules such as creatinine, chlorinated creatinine products and arginine could be effectively treated with activated Peroxymonosulfate. Ammonium ion was oxidized only by chlorine species and only in de-ionized water. Chlorine species were formed from the reaction of sulfate radicals with chloride ions. In pool water, the reaction of sulfate radicals with chloride ions and the subsequent ammonium ion oxidation were scavenged by the presence of bicarbonate ions. The Co/Peroxymonosulfate system was also shown to be an effective disinfection reagent, since 99.99% (4-log) kill of E. coli was achieved in 60 min of treatment. At the concentrations tested here, however, it is still not efficacious enough to qualify as an EPA-registered sanitizer for swimming pools (requires 6-log kill of E. coli, ATCC 11229, and Enterococcus faecium, ATCC 6569, in 30s).

  • chemical and microbial decontamination of pool water using activated Potassium Peroxymonosulfate
    Water Research, 2008
    Co-Authors: George P Anipsitakis, Thomas P Tufano, Dionysios D Dionysiou
    Abstract:

    Abstract Potassium Peroxymonosulfate activation leads to the formation of highly reactive species, mainly the sulfate radicals. Activated Potassium Peroxymonosulfate (from now on Peroxymonosulfate) was tested against specific pollutants such as ammonium ion, creatinine, chlorinated creatinine products, arginine and Escherichia coli ( E. coli ), all constituents or derivatives of human discharges. The objective was to assess whether activated Peroxymonosulfate can be a viable treatment reagent in recreational water applications. It was found that organic molecules such as creatinine, chlorinated creatinine products and arginine could be effectively treated with activated Peroxymonosulfate. Ammonium ion was oxidized only by chlorine species and only in de-ionized water. Chlorine species were formed from the reaction of sulfate radicals with chloride ions. In pool water, the reaction of sulfate radicals with chloride ions and the subsequent ammonium ion oxidation were scavenged by the presence of bicarbonate ions. The Co/Peroxymonosulfate system was also shown to be an effective disinfection reagent, since 99.99% (4-log) kill of E. coli was achieved in 60 min of treatment. At the concentrations tested here, however, it is still not efficacious enough to qualify as an EPA-registered sanitizer for swimming pools (requires 6-log kill of E. coli , ATCC 11229, and Enterococcus faecium , ATCC 6569, in 30 s).

  • transition metal uv based advanced oxidation technologies for water decontamination
    Applied Catalysis B-environmental, 2004
    Co-Authors: George P Anipsitakis, Dionysios D Dionysiou
    Abstract:

    Abstract This study explores the effect of ultraviolet (UV) light radiation and/or transition metals (M) for the activation of common oxidants (Ox) with the objective of treating recalcitrant organic contaminants in water. Hydrogen peroxide, Potassium Peroxymonosulfate and Potassium persulfate were combined with iron, cobalt and silver, respectively, and/or with UV light (254 nm) and were tested for the treatment of 2,4-dichlorophenol (2,4-DCP). Results from our previous studies indicated that these particular transition metals are the best catalysts for the activation of the respective oxidants [G.P. Anipsitakis, D.D. Dionysiou, Environ. Sci. Technol. 37 (2003) 4790; G.P. Anipsitakis, D.D. Dionysiou, Environ. Sci. Technol. 38 (2004) 3705]. From the combined use of UV, the oxidants and the transition metals, four general categories of advanced oxidation technologies were evaluated and compared for the degradation and mineralization of 2,4-DCP. Those were (i) the dark conjunction of each oxidant with its favorable metal activator (M/Ox), (ii) the use of UV alone, (iii) the combination of UV with each oxidant (UV/Ox) and (iv) the use of UV combined with each metal/oxidant systems (UV/M/Ox). In particular, the systems UV/KHSO5, UV/Co(II)/KHSO5 and UV/Ag(I)/K2S2O8 and the sulfate radicals generated thereby have never been tested before for water decontamination, as opposed to the extensively investigated hydroxyl radicals generated by UV/H2O2 and the photo-Fenton. The comparison of the results with respect to the transformation of 2,4-DCP and the extent of organic carbon removal led to the construction of the following order of efficiencies: UV/K2S2O8 > UV/KHSO5 > UV/H2O2 for the UV/Ox processes and UV/Fe(III)/H2O2 > UV/Fe(II)/H2O2 > UV/Co(II)/KHSO5 > UV/Ag(I)/K2S2O8 for the UV/M/Ox processes tested here. All experiments were homogeneous and conducted at ambient room temperature. The relative absorbance of the species participating in the reactions supports the former order of efficiency, since persulfate followed by Peroxymonosulfate were proven more photosensitive than hydrogen peroxide. Among the metals tested, only iron species such as Fe(OH)2+ were found to absorb strongly at 254 nm and to this is attributed the higher efficiencies obtained with the photo-Fenton reagents.

Thomas P Tufano - One of the best experts on this subject based on the ideXlab platform.

  • chemical and microbial decontamination of pool water using activated Potassium Peroxymonosulfate
    Water Research, 2008
    Co-Authors: George P Anipsitakis, Thomas P Tufano, Dionysios D Dionysiou
    Abstract:

    Abstract Potassium Peroxymonosulfate activation leads to the formation of highly reactive species, mainly the sulfate radicals. Activated Potassium Peroxymonosulfate (from now on Peroxymonosulfate) was tested against specific pollutants such as ammonium ion, creatinine, chlorinated creatinine products, arginine and Escherichia coli ( E. coli ), all constituents or derivatives of human discharges. The objective was to assess whether activated Peroxymonosulfate can be a viable treatment reagent in recreational water applications. It was found that organic molecules such as creatinine, chlorinated creatinine products and arginine could be effectively treated with activated Peroxymonosulfate. Ammonium ion was oxidized only by chlorine species and only in de-ionized water. Chlorine species were formed from the reaction of sulfate radicals with chloride ions. In pool water, the reaction of sulfate radicals with chloride ions and the subsequent ammonium ion oxidation were scavenged by the presence of bicarbonate ions. The Co/Peroxymonosulfate system was also shown to be an effective disinfection reagent, since 99.99% (4-log) kill of E. coli was achieved in 60 min of treatment. At the concentrations tested here, however, it is still not efficacious enough to qualify as an EPA-registered sanitizer for swimming pools (requires 6-log kill of E. coli , ATCC 11229, and Enterococcus faecium , ATCC 6569, in 30 s).

  • chemical and microbial decontamination of pool water using activated Potassium Peroxymonosulfate
    Water Research, 2008
    Co-Authors: George P Anipsitakis, Thomas P Tufano, Dionysios D Dionysiou
    Abstract:

    Potassium Peroxymonosulfate activation leads to the formation of highly reactive species, mainly the sulfate radicals. Activated Potassium Peroxymonosulfate (from now on Peroxymonosulfate) was tested against specific pollutants such as ammonium ion, creatinine, chlorinated creatinine products, arginine and Escherichia coli (E. coli), all constituents or derivatives of human discharges. The objective was to assess whether activated Peroxymonosulfate can be a viable treatment reagent in recreational water applications. It was found that organic molecules such as creatinine, chlorinated creatinine products and arginine could be effectively treated with activated Peroxymonosulfate. Ammonium ion was oxidized only by chlorine species and only in de-ionized water. Chlorine species were formed from the reaction of sulfate radicals with chloride ions. In pool water, the reaction of sulfate radicals with chloride ions and the subsequent ammonium ion oxidation were scavenged by the presence of bicarbonate ions. The Co/Peroxymonosulfate system was also shown to be an effective disinfection reagent, since 99.99% (4-log) kill of E. coli was achieved in 60 min of treatment. At the concentrations tested here, however, it is still not efficacious enough to qualify as an EPA-registered sanitizer for swimming pools (requires 6-log kill of E. coli, ATCC 11229, and Enterococcus faecium, ATCC 6569, in 30s).

Wojciech J. Stec - One of the best experts on this subject based on the ideXlab platform.

Lucyna A. Woźniak - One of the best experts on this subject based on the ideXlab platform.