A study on the removal of metals from nuclear waste and the electrochemical reduction of nitrate and nitrite at three dimensional electrodes /
The electrochemical treatment of the low level nuclear waste solution was studied to find the 'possibility of the use of the packed bed electrode and fluidized bed electrode. Among the possible electroactive species in the waste, the electrochemical depositions of Hg(li) and Ru-nitrosy...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=743273701&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The electrochemical treatment of the low level nuclear waste solution was studied to find the 'possibility of the use of the packed bed electrode and fluidized bed electrode. Among the possible electroactive species in the waste, the electrochemical depositions of Hg(li) and Ru-nitrosyl complex and the electrochemical reductions of chromate, nitrate, and nitrite were studied at several planar electrodes in 1.33 M NAOH solution to corinect the results to the packed bed electrode and the fluidized bed electrode. HgO is reduced to Hg at a Ni electrode with the equilibrium potential of +0.09 V vs Normal Hydrogen Electrode (NHE). One of the ruthenium complexes 'in the waste, [RuNO(NO,),OH]'-, is reduced to Ru metal at a Ni electrode with the half wave potential of -0. 3 8 V vs NHE. Chromate is reduced to chromic hydroxide which inhibits other reactions due to the low conductivity of the hydroxide film at a Ni electrode with the equilibrlw-n potential of -0.24 V vs NHE in the alkaline solution. Chromate is reduced to a soluble Cro2- at a Ph electrode which does not inhibit other reaction. The reduction of nitrate is a consecutive reduction to nitrite and to nitrogen or ammonia. The reduction is activation controlled until the applied potential is more cathodic than -1.2 V at which the hydrogen evolution reaction is significant. The composition of the products of the nitrate reduction is strongly dependent on the electrode materials. The electrochemical responses of the packed bed electrode were developed with the electrochemical responses at planar electrodes and the IR drops through the solution phase and the particle-particle contact. A modellistic approach for the fluidized bed electrode was tried as an expanded packed bed concept. The packed bed electrode is better than the fluidized bed electrode when the IR drops are considered. Designing a plant for the electrochemical treatment for the waste is tried to show that the process will give benefits economically and environmentally. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xx, 329 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |