Author : Wesam Gaber Nasr Kandeel
Degree : M.Sc. Chemical
Title:
Desalination Using
Different Pertration Techniques
Abstract
SUMMARY In the present work,
desalination using the present type of supported liquid membrane (SLM) and the
bulk liquid membrane (BLM) techniques have been investigated in the
desalination of saline water. For the SLM, a simple apparatus devised and
constructed in our lab, was used to conduct the experiments. Various factors
that would affect the progress of desalination were studied and these were:
concentration of simulated sea water in DP, presence of emulsifier or mobile
carrier (MC) in the LM, concentration of MC in LM, presence of polyelectrolyte
(sequestering agent (SA)) in the RP, presence of magnetic stirring, and speed
of stirring. The volume ratio ofDP to RP was kept constant at 2:1. Type and
thickness of LM (1,2 dichloroethane) was kept constant. Cellophane constituted
the support for the LM. The results obtained indicated that the present type of
SLM desalination is not a promising technique, which requires further profound
study and investigation. The most important findings emphasized the importance
of the presence of a MC in the LM to enhance mass transfer through the LM and
that an optimum concentration of MC existed. Also the importance of stirring in
promoting mass transfer by minimizing the boundary layer adjacent to the
cellophane support was clarified. The best conditions arrived at were, MC =
0.1286 g (Crown ether (CE)), SA = 0.5 g (soluble starch (S.S)), slow stirring
(100 rpm) of DP and using DCE as LM, 2 mm thick. The minimum time was found to
be very long, during which total desalination might have taken place. As
regards desalination using the BLM, a simple apparatus devised and constructed
in our lab was used to conduct the experiments. Variables, which would affect
the degree of desalination were investigated, and these were: volume ratio of
DP to RP, presence of SA in the RP, quantity and type of organic LM and presence
ofMC in the LM and its quantity. Stirring speed and volume ofLM were kept
constant at 100 rpm and 130 ml respectively. The results showed that all the
variables had an effect on the progress of desalination to different extents.
The results were presented as (Ct/Co)-time curves, concentration-time curves
and mass-time curves in the DP and RP and in the LM phases. It was found that
desalination using the BLM technique was much more promising and rapid than the
SLM technique. Using the BLM technique, complete desalination could be effected
in almost 8 hrs under the best conditions used in the present work which were,
DP = 150 ml and RP = 50 ml (DP : RP = 3 : 1), MC = 0.175 g , SA = 0.5 g of
soluble starch, DCE as LM and volume ofLM = 130 ml, accompanied with slow
stirring (100 rpm) ofLM.
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