College of Computer
Science and Engineering
Potential of Capacitive Deionization and
Hydro-Magnetic Desalination Technologies for the Mena Region
Date: Wednesday, Jan 23, 2019
Time: 03:00 pm
– 04:00 pm
Location: Building 24, Room 127
Dr. Moustafa Elshafei
Systems Engineering Department
King Fahd University of Petroleum and Minerals
Freshwater scarcity is one of the most challenging problems
facing the world today. Rivers, lakes, and surface ice represent only 1.2% of
the fresh water sources on earth. The MENA region accounts for over 95% of the
installed desalination plants. As such, there is a growing need in the MENA
countries to explore desalination technologies to meet their growing need for
fresh water. This talk provides an overview of two emerging desalination
technologies; Capacitive De-Ionization (CDI) technology, and Hydro-Magnetic
Desalination (HMD) technology. While the traditional techniques as thermal
desalination and Reverse osmosis are based on removing water from salt, the two
emerging technologies are based on removing salt from water.
In capacitive de-ionization systems, saline water is made to
pass between a pair of porous electrodes connected to a voltage source. CDI is
a two-step process; the first step is ion adsorption or charging that results
in a pure permeate stream where ions are adsorbed in porous charged electrodes.
Due to the presence of electrostatic field between the electrodes, there is
movement of ions such that the positive ions, cations move to the cathode and
anions towards the anode. Two layers of opposite polarity are formed at the
electrode-solution interface which is referred to as electrical double layer
(EDL) and ions are stored in these EDL’s. In the next step, voltage is reversed
so that the ions get desorbed and flows out of the CDI cell as a brine stream
and thus cause regeneration of electrodes. The problem of membrane fouling is
not present in CDI. CDI has the potential to be energy efficient, robust
technology for water desalination.
Hydro-magnetic desalination (HMD) techniques is based on ion
separation by electromagnetic forces. While CDI is a two step process, HMD is a
continuous process. CDI is suitable for desalination of brackish water with
salt concentration less than 5000 ppm. HMD can be used over a wide range of
salt concentration. Both techniques can be driven by solar energy.
HMD forces the positive salt ions to one chamber, and forces
the negative salt ions to go to a second chamber. When these two charged
chambers are electrically connected the chloride ions in the anion chamber
loses two electrons, forming chlorine gas, which can be collected and sold as a
byproduct. On the other hand, when the cation chamber receives two electrons
the water dissociate forming hydrogen gas, and react with the sodium ions
forming sodium hydroxide solution. As a result, the process produces no brine.
Instead it produces Hydrogen gas and sodium hydroxide in one chamber, and
Chlorine gas in the second chamber, in addition to the fresh water.
The revenues from selling these byproducts would also reduce
the net cost of the produced fresh water. The technology not only eliminate the
negative impact of discharging brine into the environment but could also
contribute positively to improve the environment through the use of solar
energy and conversion of CO2 to synthetic gas.
Prof. Moustafa Elshafei acquired both his MS degree and PhD
from McGill University, Montreal, PQ, Canada in 1978 and 1982, respectively;
and joined the Systems Engineering Department at King Fahd University of
Petroleum Minerals, Saudi Arabia as Professor of Control and Instrumentation
Systems Engineering in 1987. Some of his
Research Interests include Intelligent Instrumentation and Control, Process
Control and Industrial Automation, Application of Al in Oil and Gas Exploration
and Industries, and Signal and Speech Processing of Arabic Language.
Prof. Elshafei is currently working as Adjunct Professor in
the same department.
researchers and graduate students are invited to attend.
Department, College of Computer Sciences and Engineering
Telephone: +966 (13)
860 2988, Email: firstname.lastname@example.org, Website: www.kfupm.edu.sa/departments/se/
Copyright © 2014 King
Fahd University of Petroleum & Minerals