The mechanism for free chlorine oxidation of reduced manganese in mixed-media filters

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dc.contributor.authorOcciano, Suzanneen
dc.contributor.committeechairKnocke, William R.en
dc.contributor.committeememberBoardman, Gregory D.en
dc.contributor.committeememberHoehn, Robert C.en
dc.contributor.departmentEnvironmental Sciences and Engineeringen
dc.date.accessioned2014-03-14T21:41:57Zen
dc.date.adate2012-08-01en
dc.date.available2014-03-14T21:41:57Zen
dc.date.issued1988-12-05en
dc.date.rdate2012-08-01en
dc.date.sdate2012-08-01en
dc.description.abstractThe removal mechanisms of soluble manganese [Mn (1l)] through mixed-media filters were investigated. Experimentation was directed toward the continuous supply of an oxidant during column filter studies. Free chlorine (HOCl, OC1â ) was chosen to increase soluble manganese removal efficiency because chlorine is readily available and inexpensive. Filter media from four different water treatment plants were used in this study. Continuous-flow filter columns were operated in the presence and absence of 2.0 milligrams per Liter (mg/ L) free chlorine. Maintaining constant influent manganese concentrations of 1.0 mg/L and flow rates of 2.5 gallons per minute per foot squared (gpm/ft2), the operational pH values of 6-6.2, 7.8 and 8.8 were investigated. Results indicate that a continuous feed of free chlorine (2 mg/L) applied to the filter columns could increase manganese (II) removal efficiency. However, the amount and oxidation state of the MnOx(S) surface coating initially on the media and the influent pH had major influences upon the uptake of soluble manganese. From numerous Mn (II) uptake studies with different media and varying pH conditions, oxide-coated filter media continuously regenerated with free chlorine could result in increased soluble manganese removal through adsorption upon the MnOx(s) surface coating and subsequent oxidation directly on the media surface. The relationships of manganese removal and chlorine consumed were also explored. To further investigate the mechanisms of free chlorine oxidation for the removal of reduced manganese, pH 5.0 backtitrations were conducted following exhaustion of the filter media. The exposure of such low pll conditions to columns operated in the presence and absence of HOCI would ascertain if oxidation of the adsorbed Mn²⁺ was always occurring, regardless of an oxidant feed. Results indicated that in the absence of HOCI, the mechanisms for manganese removal on oxide-coated filter media were adsorption only. With the additional of HOCI, the adsorbed Mn²⁺ is oxidized directly on the surface of the media, thereby, continuously regenerating the surface oxide coating. Additional work was begun to ascertain if free chlorine could be used as a viable alternative to potassium permanganate (KMnO₄) regeneration of oxide-coated filter media. Preliminary findings indicate from column cycling experiments that free chlorine could be used to regenerate oxide-coated filter media prior to backwashing.en
dc.description.degreeMaster of Scienceen
dc.format.extentxi, 98 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-08012012-040338en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08012012-040338/en
dc.identifier.urihttp://hdl.handle.net/10919/44082en
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1988.O224.pdfen
dc.relation.isformatofOCLC# 19608567en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1988.O224en
dc.subject.lcshWater -- Purification -- Filtrationen
dc.subject.lcshWater -- Purification -- Manganese removalen
dc.titleThe mechanism for free chlorine oxidation of reduced manganese in mixed-media filtersen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineEnvironmental Sciences and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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