Catalyzed Calcium Peroxide as Treatment Technology for Organic Compound Contaminated Soil and Groundwater
Author
de Jong, Barend
Term
4. term
Education
Publication year
2019
Submitted on
2019-06-07
Pages
91
Abstract
Dette studie undersøgte calciumperoxid som en fast kilde til hydrogenperoxid til at drive en avanceret oxidationsproces til rensning af vand og jord ved neutral pH. I vand blev benzoesyre nedbrudt ved neutral pH ved brug af jern(II), holdt i opløsning af chelateringsmidler—citronsyre eller oxalsyre—som katalysator. Et 1:1-forhold mellem oxidant og katalysator gav den bedste ydelse. I en jordslurry (en blanding af jord og vand) blev 98% af den oprindelige benzoesyre fjernet med et 1:1-forhold mellem oxidant og katalysator og et 100:1-forhold mellem oxidant og forurening. Kraftigt tetrachlorethylen (PCE)-forurenet jord blev også behandlet: op til 77% PCE-fjernelse blev opnået med calciumperoxid aktiveret af jern(II) cheleret med oxalsyre. Kolonneforsøg viste, at calciumperoxid effektivt kan frigive hydrogenperoxid i mindst 8 timer; udløbskoncentrationen af hydrogenperoxid blev ikke påvirket af flowhastigheden. Lavere temperatur øgede den samlede mængde frigivet hydrogenperoxid. Resultaterne peger på, at calciumperoxid-baseret avanceret oxidation kan nedbryde udvalgte organiske forureninger i vand og jord ved nær-neutral pH.
This study investigated calcium peroxide as a solid source of hydrogen peroxide to drive an advanced oxidation process for cleaning water and soil at neutral pH. In water, benzoic acid was degraded at neutral pH using iron(II) kept soluble by chelating agents—citric acid or oxalic acid—as a catalyst. A 1:1 ratio of oxidant to catalyst gave the best performance. In a soil slurry (a mixture of soil and water), 98% of the initial benzoic acid was removed using a 1:1 oxidant:catalyst ratio and a 100:1 oxidant:contaminant ratio. Heavily tetrachloroethene (PCE)–contaminated soil was also treated: up to 77% PCE removal was achieved with calcium peroxide activated by iron(II) chelated with oxalic acid. Column experiments showed that calcium peroxide can release hydrogen peroxide effectively for at least 8 hours; the outlet hydrogen peroxide concentration was not affected by flow rate. Lower temperatures increased the total amount of hydrogen peroxide released. These results indicate that calcium peroxide–based advanced oxidation can degrade selected organic pollutants in water and soil under near‑neutral pH.
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