Catalyzed Oxidation and the Future of Mold Stain Removal and Cleaning
By Matt Mills
When presented with a challenging remediation project, a company typically must choose to put its focus on either the use of labor or chemicals, particularly for tasks like stain and odor removal. Manual scrubbing can help with some stains, but labor costs are expensive. Chemical cleaning products usually can enhance cleaning efforts, but they can be hazardous if used incorrectly.
Obviously, the ideal solution would feature a non-hazardous cleaning product that performs thoroughly while also working quickly to cut down on labor requirements. While steady progress is being made across the industry in this regard, it feels like it has been some time since a major advancement emerged. However, a new development offers hope toward this goal in one product class: oxidative cleaning products.
What are oxidative cleaning products?
While the name might make them sound complex and unfamiliar, oxidative cleaning products are incredibly common and include well-known names like hypochlorite and hydrogen peroxide, among others. There are many products in the restoration field that contain these compounds and act as cleaning and bleaching agents.
Oxidation is an important aspect of cleaning and restoration, especially for stain and odor removal. Many dark-colored stains, such as wine and coffee stains or the stains left behind by mold and mildew, are made up of chemical compounds that contain chromophores, which are parts of molecules that readily absorb light. Cleaning products that contain oxidants break up these chromophores through a chemical process, resulting in apparent disappearance of these stains, or bleaching.
A similar process occurs with odorous compounds. Many chemicals that comprise bad odors contain sulfur or nitrogen. Oxidizing the sulfur and nitrogen atoms on these molecules mitigates the smell.
Products that use oxidative chemistry can be highly effective when used properly but are potentially dangerous to use, especially in high concentrations. Hypochlorite has a strong chlorine smell, is irritating to the nose and eyes, and is caustic. Cleaning products that contain hydrogen peroxide do not have an odor but generally require higher concentrations of peroxide and/or are not as active as hypochlorite.
Reducing the concentration of hazardous chemicals in cleaning products while maintaining the required performance would improve the safety of workers, homeowners, and the environment. One potential way to do this is to introduce a catalyst.
How does a catalyst change cleaning?
A catalyst is a chemical that accelerates the rate of a reaction but is not consumed during the reaction. Catalysts are abundant in industry, from gasoline production to making fertilizer to breaking down harmful byproducts from vehicle exhaust. Enzymes are highly efficient biological catalysts that perform all manner of chemical reactions that enable life.
There are several classes of enzymes that perform oxidation chemistry such as peroxidase and cytochrome p450. It is possible to use enzymes directly to catalyze cleaning reactions; however, these enzymes are susceptible to degradation in harsh cleaning environments. Alternatively, catalysts can be designed that mimic the function of enzymes and are referred to as
“biomimetic catalysts.”
One applied research study performed over several years at Carnegie Mellon University resulted in synthetic catalysts modeled after peroxidase enzymes that were developed using iron as the catalytic site combined with the biologically compatible elements carbon, nitrogen, hydrogen, oxygen, and sulfur. These synthetic catalysts increase the rate of oxidation reactions by hundreds to thousands of times, and when a small amount is added to a cleaning solution, the concentration of the oxidant can be cut five- to ten-fold while maintaining the same level of performance.
In some cases, this also enables the use of a lower-strength oxidant, such as hydrogen peroxide, to replace a higher strength oxidant like hypochlorite. Using a lower concentration of chemicals, or using less potent chemicals, increases job site safety—by limiting employee interactions with hazards—and customer satisfaction—by reducing the chemical smell. Environmentally, there are fewer harmful byproducts produced, and less energy is used to produce and transport these chemicals. This is especially the case with hypochlorite, as its use can result in chlorinated byproducts.
Catalyzed oxidation in remediation
Because of the enhanced capabilities, products that utilize catalyzed oxidation are beginning to be used to address some of the most challenging cleaning tasks. Mold remediators are quickly benefiting from the introduction of this technology, especially in response to dark staining left behind from mold contamination, which is difficult to remove without chemical treatment.
Conventional products on the market contain sodium hypochlorite at concentrations of 5-8% and leave behind a strong chlorine smell. This is hazardous to workers and unpleasant to the occupants of a treated building. Addition of a small amount of synthetic catalyst modeled after peroxidase yields the same stain removal performance at just under 1% hypochlorite concentration, which leads to greatly decreased odor and improved user experience. This can also enable a remediator to rely on the chemical, rather than manual cleaning and scrubbing, saving on labor costs and shortening project time.
Products using biomimetic catalysts also are being developed to tackle a wider range of difficult cleaning and restoration challenges. In a short time, this nature-inspired chemistry should be making the lives of cleaning and restoration contractors much easier.
As Sudoc’s director of research and development, Matt Mills, seeks to transform the vast potential of TAML™ catalysts into products that serve a wide variety of needs. Prior to Sudoc, Mills worked at Carnegie Mellon University with Professor Terry Collins, a Sudoc founder and inventor of TAML catalysts, where he studied the ins and outs of chemistry for five years. Visit www.sudoc.com for more information.