Regulatory and Environmental Consulting
Gazing Into the Future...
DETERGENTS FOR THE NEW MILLENIUM
By Nathan Schiff, Ph.D.
Associate Editor - Institutional, FABRICARE
Most detergents today consist of: surfactants, builders and solvents. The surfactants lower the surface tension of water, allowing the detergent to penetrate into the soil on the fabric. Builders break this soil up enabling the surfactants to emulsify it. Solvents physically dissolve some of the soils, making it easier for the remainder to be rinsed off.
Today's detergents were developed at a time, when we knew less about the long-term effect which some chemicals can have on the environment. It wasn't until we saw the pictures of Earth taken from space that we realized the importance of preserving this planet we live on. From that time on, environmental concerns have become an urgent issue and the development of environmentally- friendly products in many fields has been carried out at an accelerated pace. In the detergent field, there has been much focus on the need for environmentally-friendly solvents, builders and surfactants.
Chlorinated solvents and some water-soluble glycol ether solvents used in degreasers are now known to have a detrimental effect on the earth's protective ozone layer. They are also one of the most common polluters of groundwater. These solvents are classified as VOCs (volatile organic compounds) and are also indirectly responsible for polluting the air we breath, as well as the groundwater we drink.
Recently, Argonne National Laboratories developed and patented a cost-effective process for manufacturing ethyl lactate which is a high powered solvent. It is made from the fermentation of corn and other renewable carbohydrate sources. Ethyl lactate is comparable to chlorinated solvents in its power as a solvent. In addition, it is totally biodegradable, does not emit VOCs and requires one-tenth the energy to
produce, compared to chlorinated or other solvents. Economically, it will soon be feasible to replace 80% of the environmentally-damaging solvents with ethyl lactate.
Conventional builders such as phosphates can exhibit long-term detrimental effects on the environment. For example: phosphates entering the Great Lakes resulted in the growth of oxygen-consuming algae. This algae caused the amount of oxygen in the water to be depleted to such an extent that it was killing fish.
Tomorrow's answer for this problem will be found in biological processes, using specialized enzymes and bacteria. I will discuss the application of bacteria in soil remediation from petroleum spills in a future article.
All enzymes are proteins, derived from plants, animals and bacterial sources. Enzymes are very specific for a certain class of soil. They break down the soils on fabrics into biodegradable units. Protease enzymes specialize in breaking down the protein soils at relatively low temperatures. Similarly, lipase enzymes are specific for breaking down oil and grease soils.
Enzymes are proteins which are made up of hundreds of amino acids (their building blocks), connected to each other and forming a very long chain. Within this chain, there exists an area containing a small number of amino acids, referred to as the active site, which are responsible for the enzyme's activity. By isolating theses sites, and stripping away the non-active portion of the enzyme molecule, it is possible to develop a highly potent and rapid acting enzyme preparation.. Scientists are also manipulating the active area of the enzyme, in order to devevelop heat-resistant enzymes which can function at temperatures close to the boiling point of water.
Surfactants are molecules in which one end contains an oil-loving component, and the opposite end is made up of a water-seeking component. The differences between surfactants are in the relative amount of oil-loving to water-loving components. changing this ratio provides for a range of surfactants which can act upon different soils.
During emulsification, the oil-loving end of the surfactant molecule dissolves into the oily soil (like attracts like). Since the opposite end of the surfactant molecule is water-loving, the addition of water results in the formation of an emulsion, which is readily rinsed off.
Scientists are now at work developing "designer surfactants" which will provide 100% efficiency on specific soils. The actual soil which the surfactant is designed to remove is incorporated into the surfactant. The resulting product is a surfactant with an oil-loving portion identical to the soil it is designed to remove. This specialized surfactant is now optimized to remove very specific soil. For that reason only a very small amount is required compared to today's surfactants.
IMAGINE THIS STAIN …
REMOVAL IN THE FUTURE
Suppose a fabric is stained with colored candle wax . The detergent of the future will contain a mixture of ethyl lactate solvent, candle wax specific surfactants and active enzyme centers specific towards degrading the candle wax. On application, the designer surfactant rapidly emulsifies the wax. The ethyl lactate, being a powerful solvent, dissolves it and the designer active enzyme centers break down the wax and its color into carbon dioxide and water.
Welcome to the New Millennium!
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