Effect of permeation of discharge characteristics of capacitive deionization process

Cost-effective desalination of seawater can be a panacea for the growing freshwater crisis that ranks alongside the problems of shortage of viable energy resources and global warming in terms of its frightening global spread and magnitude. However, the energy guzzling nature of the existing desalination technologies has resulted in very limited relief characterized by a meager 0.3% contribution to the annual water use. In recent years, capacitive deionization (CDI) has been reported to potentially solve some of the crucial issues that have plagued the classical desalination processes. CDI is a low-pressure, non-membrane desalination technology that employs the basic electrochemical principle of adsorbing ions in a capacitive fashion to high surface-area electrodes such that the outgoing stream becomes devoid of the ions that were present in the incoming stream. Although the power efficiency of CDI is nearly an order-of-magnitude superior to the existing processes, it is plagued by the problem of low water recovery ratio. The costs of pumping and pre- and post-treatment of water added to the rising costs of surface water makes maximizing the recovery ratio a priority. Moreover, the throughput of the plant is related to the water recovery ratio. To drastically reduce the problem of low water recovery ratio while still maintaining the sizeable power consumption advantage of the CDI process, we propose a capacitive deionization process with permeating flow discharge (PFD). In PFD, the waste water is permeated through the porous electrodes rather than flowing in-between the electrodes as is the case in the conventional axial flow discharge (AFD) process.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Barman, Ishan

Advisor dc:contributor.advisor

• Nam P. Shuh.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/42302

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/42302