Distillation.
www.wholesalewaterdistillers.com
They have a one gallon counter top distiller for ~$100, even available
with a glass
collection jug.
Janet
Dan Nave wrote:
Steve,
Are you aware of any methods to remove fluoride from city water?
Dan
On Mon, Jul 19, 2010 at 10:40 PM, Norton, Steve <stephen.nor...@ngc.com> wrote:
This is interesting. A study has shown that silver nanoparticles completely
remove endosulfan, malathion and chlorpyrifos from water. The mechanism of
removal is adsorption followed by catalytic destruction. A household filter
that uses the technology to remove pesticides from water has been developed.
- Steve N
http://www.rsc.org/chemistryworld/News/2007/April/20040701.asp
Pesticide filter debuts in India
A domestic water filter that uses metal nanoparticles to remove dissolved
pesticide residues is about to enter the Indian market. Its developers at
the Indian Institute of Technology (IIT) in Chennai (formerly Madras)
believe it is the first product of its kind in the world to be
commercialised.
Mumbai-based Eureka Forbes Limited, a company that sells water purification
systems, is collaborating with IIT and has tested the device in the field
for over six months. Jayachandra Reddy, a technical consultant to the
company, expects the first 1000 units to be sold door-to-door from late May.
'Our pesticide filter is an offshoot of basic research on the chemistry of
nanoparticles,' Thalappil Pradeep who led the team at IIT Chennai
told Chemistry World. He and his student Sreekumaran Nair discovered in 2003
that halocarbons such as carbon tetrachloride (CCl4) completely break down
into metal halides and amorphous carbon upon reaction with gold and silver
nanoparticles1.
Pradeep said this prompted them to extend their study to include
organochlorine and organophosphorous pesticides, whose presence in water is
posing a health risk in rural India. In research funded by the Department of
Science and Technology in New Delhi, his team found2,3 that gold and silver
nanoparticles loaded on alumina were indeed able to completely remove
endosulfan, malathion and chlorpyrifos - three pesticides that have been
found at elevated levels in Indian water supplies.
Use and recycle
The mechanism of removal is 'adsorption followed by catalytic destruction',
Pradeep explained. 'The chemistry occurs in a wide concentration range of
environmental significance.' He added that tests proved silver particles
from the filter are not released into the water. The IIT study found that
gold particles perform better in the case of endosulfan. However, for cost
reasons, the commercialised filters use only silver particles, which range
in size from 60 to 80 nanometres at a concentration (on their alumina
support) of 33 parts per million.
'Based on consumption patterns of a typical Indian household, the filter is
designed to have enough nanomaterials to provide 6000 litres of
pesticide-free water for one year,' Pradeep said. 'After that, the company
will recycle the filters to recover the silver.'
Use of nanoparticles for environmental remediation is an emerging area of
research worldwide. Nanoscale iron powders had been shown to degrade other
pesticides, including DDT and lindane4, 'and there are reports about the use
of nanomaterials for removing arsenic, heavy metals and fluorides,' said
Pradeep. 'But ours is the first product to hit the market,' he said.
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