No more draught…

North eastern Australia scarce much in water and many projects were launched to improve the water level of this area but non was fruitful.Of this the importance was given to a  mechanical process called reverse osmosis. What this process does is the desalination of salt water which is much abundantly available in those areas.But this process requires the cleaning, replacement  etc of the semi permeable membrane through which the salinated water has to be passed under high pressure.Another method uses electric field to drive ions across membranes.But all this measures didn’t worth much and owing to its high cost couldn’t make an impact on water scarce areas.

So resembling the latter technology a new technology was introduced named CDIs technology ie the Capacitive Deionization Technology,here there is no need of membrane for the desalination process.It works on the principle that,in salt water the salt  exists as positive and negative ions and the water is made to pass through oppositely charged porous electrodes,then the positive charges get drifted into the pores of negative electrode and negative to pores of positive electrode leaving behind a deionized desalinated water.Once the pores of the the electrodes get fully filled with ions the process is stopped and the polarity of the electrodes are reversed,then the ions get repelled and is flushed out using a stream water a real super salty brine.

The method was effective but the rapid saturation of electrodes make this process little inconvenient so researches began to increase the capacity of the electrodes.As a result , Lawrence Livermore National Laboratory  made an electrode from conductive carbon aerogel,a material with surface area of about 260 million times its volume.Can you imagine how huge is that ie a grape size piece of that object has the surface area of two basketball court..really awesome..so that kind of electrode was able to work with out saturation for a longer period but these electrodes are prone to bacterial infections in water.

BOb Campbell CEO of California based Campbell applied physics was able to rectify this problem.His team developed  an  ozone based technology which could kill bacterias  before entering it into the pores of the electrode.

The main reason that this method was not noticed was the high domination of reverse osmosis process in the  market.Though the  reverse osmosis process is much cost effective and efficient for water with high salt content like sea water,CDi technology is more suitable for inland desalination purposes that is needed more in many countries.Many countries have only started experiencing the problem of inland water salination so the technology is not emerged much.Australia is the country which is experiencing it much severely and they are going to  implement this project soon.Will followed by many countries in near future.

Though reverse osmosis is effective for sea water desalination it cannot remove Boron ions from salt water but this could be effectively done using CDIs technology.This technology will be a great boon to the world where pure water is depleting very rapidly.

Written by arjun on November 16th, 2008 with 1 comment.
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