Laundry tablets go green all over
India TV News
8 March 2062
Boxes containing a year’s supply (100) of the new detergent capsules, Green Clean, will soon be on sale in supermarkets across India and are made entirely from renewable resources. Research chemists at IndiaChem, Bangalore, have finally solved the problem of making all the ingredients this way.
“The most difficult challenge we faced was finding a chemical that would neutralise the calcium of hard water”, said Donald Patel, their head chemist, “but in the end we returned to using sodium tripolyphosphate which can be manufactured from the phosphate extracted from sewage works.”
Dr Patel pointed out that although this chemical was once accused of causing river and lake pollution, its removal from waste waters no longer made it a threat and it is recycled as raw material for the chemical industry.
The other ingredients, the surfactants, the dirt solubilisers, the dye stabilisers, the whitening agents, the fabric softeners, and even the bleaches are now made from chemicals obtained from crops, including straw and bark, or from the minerals got from sea water.
“Green Clean works at room temperature, and using a minimum volume of water” added Patel, pointing out that last year saw the launch of a new washing machine for India in which the rinse water from one wash is disinfected and stored to be used for the main wash next time. “We can now boast that washing clothes is as environmentally friendly as it is possible to be” he said.
The various ingredients in the new detergent are microencapsulated in coatings which ensure that they release their chemicals at the right time, and the whole 50 gram of detergent is sealed in a water-soluble polymer, polyvinyl alcohol, which is also produced from plant materials.
Our science correspondent writes
Detergent tablets are some of the most sophisticated household chemicals, with up to a dozen ingredients. They contain alkali and surfactants to remove grease, and enzymes to remove food residues (mainly carbohydrates and proteins) and from all kinds of surfaces (crockery, plastics, cutlery, and glass), plus something to bleach tea and coffee stains. They also need to include a water softener, because most domestic water in the UK is hard and ion exchangers are no longer and integral part of dishwashers, and zinc additives to protect glass, which they do by replacing leached-out sodium ions. Finally there has to be a rinse aid so that the final rinse water drains off completely and does not cause ‘spotting’. Until a few years ago it seemed unlikely that all these ingredients could be made from renewables. Now they can.
The chemistry is also complicated in that the new tablets contain ingredients that are chemically incompatible and so have been microencapsulated in coatings which not only isolate and protect them but which ensures they dissolve and release their contents in a controlled fashion and at the right time. They are all sealed in the water-soluble polymer, polyvinyl alcohol, which is also produced enzymatically from plant crops.
And how is the final rinse water sterilised? This is done by subjecting it briefly to pressures high enough to burst the membranes of any bacteria it contains.