14
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Degradation of organic pollutants by NiFe 2O 4/peroxymonosulfate: efficiency, influential factors and catalytic mechanism

      Read this article at

      ScienceOpenPublisher
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Catalytic performance of NiFe 2O 4/PMS system as advanced oxidation technologies in pure water and actual water was studied, and various influential factors and catalytic mechanism were also investigated.

          Abstract

          Nickel ferrites (NiFe 2O 4) were prepared through thermal decomposition of homogeneous nickel oxalate and ferrous oxalate, and the product displayed typical spinel structure, small nanoparticle size ( ca. 12 nm), high BET surface (53.5 m 2 g −1), and good magnetic response (19.3 emu g −1). The as-prepared NiFe 2O 4 was applied in heterogeneous catalysis to generate powerful radicals from peroxymonosulfate (PMS) for the removal of recalcitrant pollutant. Herein, benzoic acid (BA) was employed as a stable model organic pollutant, and it was found that NiFe 2O 4/PMS system could realize 82.5% degradation in 60 min and maintain its catalytic efficiency during four recycling experiments. Such a catalytic performance of NiFe 2O 4 was indeed superior to those from Fe 2O 3 (23.5%), Fe 3O 4 (48.0%), NiO (57.6%), and MnFe 2O 4 (63.8%). Although NiFe 2O 4 performed a slightly inferior BA degradation to CoFe 2O 4 (86.2%), its nickel leaching (0.265 mg L −1) was much less than cobalt leaching (0.384 mg L −1) from CoFe 2O 4. In addition, some potential influential factors, including the dosages of PMS and NiFe 2O 4, the initial pH value, ion strength, and the concentrations of bicarbonate, natural organic matter, halide, were systemically investigated. More importantly, NiFe 2O 4/PMS were also effective for BA removal under some actual water background conditions, especially in surface water and the finished water from drinking water treatment plant: the degradation efficiencies of BA were still close up to 60%. Sulfate and hydroxyl radicals were confirmed to be the main reactive species in the NiFe 2O 4/PMS system. XPS spectra revealed that Ni sites on the surface of NiFe 2O 4 were the primary active sites, and Raman spectra suggested that inner-sphere complexation between PMS and Ni sites derived peroxo species on the surface, which were further responsible for the efficient generation of radicals.

          Related collections

          Most cited references42

          • Record: found
          • Abstract: not found
          • Article: not found

          Critical Review of rate constants for reactions of hydrated electronsChemical Kinetic Data Base for Combustion Chemistry. Part 3: Propane

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Radical generation by the interaction of transition metals with common oxidants.

            Nine transition metals were tested for the activation of three oxidants and the generation of inorganic radical species such as sulfate, peroxymonosulfate, and hydroxyl radicals. From the 27 combinations, 14 M/Ox couples demonstrated significant reactivity toward transforming a model organic substrate such as 2,4-dichlorophenol and are further discussed here. It was found that Co(II) and Ru(III) are the best metal catalysts for the activation of peroxymonosulfate. As expected on the basis of the Fenton reagent, Fe(III) and Fe(II) were the most efficient transition metals for the activation of hydrogen peroxide. Finally, Ag(I) showed the best results toward activating persulfate. Quenching studies with specific alcohols (tert-butyl alcohol and ethanol) were also performed to identify the primary radical species formed from the reactive M/Ox interactions. The determination of these transient species allowed us to postulate the rate-determining step of the redox reactions taking place when a metal is coupled with an oxidant in aqueous solution. It was found that when Co(II), Ru(III), and Fe(II) interact with peroxymonosulfate, freely diffusible sulfate radicals are the primary species formed. The same was proven for the interaction of Ag(I) with persulfate, but in this case caged or bound to the metal sulfate radicals might be formed as well. The conjunction of Ce(III), Mn(II), and Ni(II) with peroxymonosulfate showed also to generate caged or bound to the metal sulfate radicals. A combination of sulfate and hydroxyl radicals was formed from the conjunction of V(III) with peroxymonosulfate and from Fe(II) with persulfate. Finally, the conjunction of Fe(III), Fe(II), and Ru(III) with hydrogen peroxide led primarily to the generation of hydroxyl radicals. It is also suggested here that the redox behavior of a particular metal in solution cannot be predicted based exclusively on its size and charge. Additional phenomena such as metal hydrolysis as well as complexation with other counterions present in solution might affect the thermodynamics of the overall process and are further discussed here.
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Rate Constants for Reactions of Inorganic Radicals in Aqueous Solution

                Bookmark

                Author and article information

                Journal
                RSCACL
                RSC Advances
                RSC Adv.
                Royal Society of Chemistry (RSC)
                2046-2069
                2016
                2016
                : 6
                : 13
                : 11040-11048
                Affiliations
                [1 ]State Key Laboratory of Urban Water Resource and Environment
                [2 ]School of Municipal and Environmental Engineering
                [3 ]Harbin Institute of Technology
                [4 ]Harbin 150001
                [5 ]China
                [6 ]Department of Chemistry
                Article
                10.1039/C5RA21117D
                8fa5274a-8c9a-4d12-b4ec-26a2e9c0a4e9
                © 2016
                History

                Comments

                Comment on this article