The main objective of the invention is to provide an environment and user
friendly and efficient method for cleaning of
cotton or synthetic clothes. Our clothes get dirty with stains very frequently.
These stains are mostly organic in nature and
are due to sweating or materials like dyes, ink, turmeric, tea or coffee.
Usually detergents or bleaching compounds are
used to remove these stains. These cleaning agents convert the stains into
water soluble material which have to be properly
rinsed out. The clothes require physical handling which is time consuming
and cumbersome. Moreover, these cleaning
agents are not user or environment friendly.
Prof. M. Sharon of Department of Chemistry has developed an environment
and user friendly and efficient method of
cleaning clothes which eliminates use of polluting and allergic non-soap
detergents and bleaching compounds and are
very effective in the removal of fast stains.
In the present invention, the cleaning method comprises of mixing soap
and ceramic oxide of nano-size particle followed
by irradiation of the clothes with UV light. Ceramic oxides are biocompatible
and include titanium dioxide (TiO2) zinc
oxide (ZnO), iron oxide (Fe2O3) or tungsten oxide (WO3)
preferably TiO2 or ZnO. Nano size particles of ceramic oxides
form an electrically charged particles at the interface between the stained
clothes and detergent solution.
On irradiating the stained cloths with UV light, photogenerated electrons
and holes are formed at the interface, which
convert the stains into gases (CO2) and water soluble mineral acid
salts (hydrochloric acid salts) which may be easily
rinsed out. The gases escape into the atmosphere and need no separation.
The UV light may be from sunlight or UV light
source and duration of irradiation depends on the nature and surface
area of the stain. Typically for a 15 Watt UV light,
an irradiation period of 20 to 30 minutes is required. If the cleaning
is carried out in a washing machine, the UV light
source is fitted in the washing machine and operated by the control
panel thereof. Stains are removed by converting them
into gases and water soluble mineral acid salts. For this reason all
types of stains are effectively eliminated.
Shirts which got yellow sweat stained at the collars were soaked in
a soap solution with water containing 10g of a washing
soap and 0.1g of titanium dioxide of nano-size particles, exposed
to sunlight for 30 minutes and rinsed with water.
The shirts were completely free from the sweat stains. In several
other examples, ink or turmeric or coffee stained towels
were treated similarly and become completely free from the stains.
This present invention provides an environment
and user friendly and efficient method for cleaning clothes.
Indian patent application no. 24/MUM/2001 Patent grant no. 206020
Inventor: M Sharon