Washington: In what could make the
treatment of waster water easier, scientists have shown that a
simple inorganic compound and sunlight can help oxidise water,
by breaking down contaminants.
An international team has demonstrated that silver
orthophosphate can efficiently be used to oxidise water with
only the power of light -- in fact, the oxidisation process
can be used to convert solar energy to clean energy or break
down contaminants in water, the `Nature Materials` reported.
"With increasing worldwide interest in alternative
renewable sources of energy, as well as on the need to clean
up environmental pollution, developing materials that can be
used to efficiently convert solar energy to clean energy or to
decompose organic contaminants is a vitally important task,"
said team leader Zhiguo Yi of Australian National University.
Added team member Prof Ray L Withers: "The material we
have studied is a very simple inorganic semiconductor - silver
orthophosphate. Under visible light illumination this material
shows an amazing ability to oxidise water to release oxygen as
well as to break down organic contaminants such as methlyene
blue, Rhodamine B and other chemicals which may be undesirable
in water supplies.
"Our work here, however, has uncovered that silver
orthophosphate can be regenerated in an energy-efficient
manner by an electrochemical method."
According to the scientists, the next step will be to
look at the use of electricity to power the process.
"We are optimistic about future uses of silver
orthophosphate, although there remain problems to overcome as
electrical energy is still required to generate hydrogen and
for the material to regenerate itself. However, the results
are important and encouraging first step towards solving
energy and environmental issues," said Dr Yi.
According to the data available with the Hydraulic
Department, since June this year, Upper Vaitarna recorded
57.80 mm of rainfall followed by 45.20 mm at Vihar, 29 mm at
Tulsi, Tansa with 26.80 mm, Bhatsa 26.20 mm and Modak Sagar
recorded 14 mm of rainfall.
"There has been rainfall in the catchment but it is too
early to say that it is a positive sign as rain water is
getting percolated," the official said.
MCGM maintains that it will be able to supply 2,900 mld
till mid-July against the actual demand of 4,500 mld. "We will
review the water cut only after July 15 and an appropriate
decision will be taken," the official said.