RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS

RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS

Bibliographic Details
Main Author: Wang, Qianheng
Language:English
Published: The Ohio State University / OhioLINK 2009
Subjects:
Civil Engineering
lime sludge
Donnan dialysis
metal cations
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu1250261927
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu12502619272021-08-03T05:56:50Z RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS Wang, Qianheng Civil Engineering lime sludge Donnan dialysis metal cations <p>Lime sludge is a byproduct of drinking water production from the water softeningprocess. As the traditional land-based disposal of lime sludge can hardly meet the need ofsociety in a sustainable manner, alternative treatment methods are about to be developedin order to appropriately solve the issue. Fortunately in recent decades, the emergenceand development of membrane technologies has provided people with advanced ways tohandle environment problems. Advances in the application of ion exchange membraneprocesses for material separation exhibit promise for providing new approaches forimproving the sustainability of industrial operations.</p><p>The objectives of this study include the investigation of the fundamentalmechanism of Donnan dialysis with a cation exchange membrane and sustainabletreatment of lime sludge by this method. The research was designed to evaluate thechange in different ion concentrations on both sides of the Donnan cell as a function oftime under a variety of experimental conditions. After understanding mechanisms of thesystem, Donnan dialysis was applied for the treatment of real lime sludge. Ideally, aftertreatment, the product could be reused as material for the water softening process andthus forms a sustainable recycling system.</p><p>Initial experiments tested the process using synthetic samples and various types ofacids. Based on the results, CaSO4 and HCl were chosen for further investigation. Theexperiments presented a high recovery of calcium cations and most of the hydrogen ionsfrom the acid were exchanged to the other side for recovery. The results also verifiedDonnan equilibrium theory for this cation exchange system and provided evidence for thepossible extension of the theory to more heterogeneous solids.</p><p>According to the fundamental experiments with synthetic samples, the processwas applied for the treatment of real lime sludge. During the kinetic experiment, aninteresting phenomenon was found that the magnesium cations on the feed sideexchanged the calcium cations back as the hydrogen ions from the acid depleted. In orderto improve the quality of the sweep side solution by increasing calcium and decreasingmagnesium, the cation exchange membrane selectivity for calcium and magnesium wasevaluated. Based on the test of membrane selectivity as interpreted by fundamental ionexchange principles with respect to ion diffusion and binding strength, a batch sequenceprocess was tested to evaluate the exchange of Ca2+ for Mg2+. The results of the batchsequence experiment revealed that the depletion of hydrogen ion on sweep and thecomparatively high concentration of magnesium on the feed side promote the exchangeof Ca2+ for Mg2+.</p><p>Although at present it is difficult to achieve complete recycling due to the productof the process under these conditions, an improved system was proposed to achieve theincorporation of this technique into the water softening process to realize the sustainableusage of most materials.</p> 2009-09-24 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1250261927 http://rave.ohiolink.edu/etdc/view?acc_num=osu1250261927 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Civil Engineering
lime sludge
Donnan dialysis
metal cations
spellingShingle Civil Engineering
lime sludge
Donnan dialysis
metal cations
Wang, Qianheng
RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS
author Wang, Qianheng
author_facet Wang, Qianheng
author_sort Wang, Qianheng
title RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS
title_short RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS
title_full RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS
title_fullStr RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS
title_full_unstemmed RECOVERY OF METAL CATIONS FROM LIME SLUDGE USING DONNAN DIALYSIS
title_sort recovery of metal cations from lime sludge using donnan dialysis
publisher The Ohio State University / OhioLINK
publishDate 2009
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1250261927
work_keys_str_mv AT wangqianheng recoveryofmetalcationsfromlimesludgeusingdonnandialysis
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