DEPARTMENT OF CHEMICAL AND BIOMOLECULAR
ENGINEERING
FACULTY OF ENGINEERING
National University of Singapore
4 Engineering Drive 4 Singapore 117576
Tel: (65) 6516 2186
TOPIC/TITLE
Fax: (65) 6779 1936
Membrane distillation application in chemical
industry
SPEAKER
Prof. Maria Tomaszewska
HOST
Prof Chung Neal
DATE
2 June 2009 ( Tuesday)
TIME
3.00 p.m.
VENUE
E5 -02-32
SYNOPSIS
Membrane distillation (MD) is a separation process of components of
aqueous solutions through a hydrophobic microporous membrane. The
driving force for the mass transfer is a gradient of partial pressure of
volatile components across the membrane which results from the
difference of temperature and composition of solutions in the layers
adjacent to the membrane. The separation mechanism of the process is
mainly based on the vapour/liquid equilibrium. The permeate
composition is a function of both the temperature and the composition
of the feed.
Due to the absence of liquid transport in the MD process, components of
aqueous solutions such as salts, macromolecules, which are unable to
evaporate and diffuse across the membrane, are completely rejected.
In accordance with advantages and limitations of MD process its practical
application goes in three directions:
* preparation of pure, desalted water from different sources,
* raising of concentration of non-volatile substances of the solutions up
to a high concentration
* Recovery of volatile compounds from a solution.
So far DCMD was mainly applied to obtain high purity water as well as for
waste water treatment. The MD process has been used to separate and
recover valuable or hazardous chemicals. The results of the
concentration and purification of fluosilicic acid by MD will be presented.
The direct contact MD process was proposed for the separation of HCl
from a spent metal etching bath and for the concentration of solutions
from rinsing objects after etching.
The studies of KCl conversion with H2SO4 into KHSO4 were performed
using a reactor integrated with direct contact membrane distillation
(DCMD). The results of the novel solution will be presented.
BIOGRAPHY
Prof. Tomaszewska obtained her MSc from Department of Chemical Engineering
(1970), Szczecin University of Technology. In 1974, Prof. Tomaszewska received
her degree of Doctor of Chemical Science. Prof. Tomaszewska started her
lecturing career in 1972 and promoted as professor in year 2005. She has been
involved in the studies of membrane and membrane processes from 1976. From
1985 her research area focused on membrane distillation. She prepared
membranes from PVDF and PTFE and investigated the novel possibility of MD
application. She is also interested in ultrafiltration, nanofiltration, hybrid
processes combining adsorption on activated carbon with ultrafiltration and
application of the processes in chemical technology and environmental
protection. She studied the preparation of slow released fertilizers using
polymeric coating. Prof. Tomaszewska is a lecturer of Spring/Summer
Membrane School organized in Poland where she presents her knowledge on
membrane distillation and contactors. She serves as Vice Editor of Polish
Journal of Chemical Technology. The results of her works were published in
many domestic and international journals (about 300 papers) such as Journal of
Membrane Science, Separation Technology, Desalination, Separation and
Purification Technology, Chemical Papers, Water Research, Catalysis Today,
Separation Science, Solvent Extraction and Ion Exchange, Industrial Engineering
Chemical Research, Journal of Agriculture and Food Chemistry and Technology,
and Polish Journal of Chemical Technology. She is also co-workers of several
patent applications.
Please visit our website for more details, http://www.chbe.nus.edu.sg/