- THE MAGAZINE
Discussing neutralization leads to a better understanding of acid solution extraction combined with water and of the spraying of an acid solution as post-application treatments. Both processes should be recognized as rinse aids and, while the word "acid" does have certain negative connotations, the acid used in a formula I am familiar with is relatively weak. This acid is related to the group known as alpha hydroxy acids (AHAs) and can be found in fruits, sugar cane and, of all things, sour milk.
What does this tell you? It implies that these specific acids are relatively safe, so much so that they are also found in the cosmetic industry, where they are used to soften the skin and help create a smoother, more "youthful" appearance.
A post-application treatment with an acid rinse results in many improvements on all fabrics. The treatment's ability to provide an improved foundation or reception for protective products allows the protector (specifically a fluorocarbon resin emulsion) to lock in on the fabric easier than it would in the presence of an alkaline residue. Additionally, the fabric literally wilts and becomes softer, much like human skin. That softness cancels out the crunch you may be experiencing due to excessive cleaning residues or improper extraction techniques. Finally, an acid rinse will help prevent the browning that is often connected with excessive cleaning pressure.
This information is not new; 10 years ago ICS columnist Lee Pemberton published a pamphlet explaining the acid rinse process in detail. Pemberton evaluated the incorporation of acid into the water-extraction process. Not only was it shown that excess soils could be washed out, but a lower pH environment was produced at the same time, eliminating the separate post-application spray treatments suggested in the initial approach.
There is one variable that will pop up now and then: hard water. Water hardness is a big factor when it comes to rinsing out carpet; the harder the water, the more difficult the removal process becomes. Soft water is definitely preferred for the cleaning extraction process. A water softener is a must, especially in areas where hard water is established, and is more beneficial than simply blending with a cleaning product at lower dilution ratios.
The drought currently being experienced across the nation will increase hard water numbers, leading carpet cleaners to assume, incorrectly, that their cleaning product has been changed, as it is not performing in the usual manner. Check with your water distributor, who should have day-to-day hardness test results, perhaps even hour-to-hour. This is an important step to take; there is great concern in Arizona, for example, that, due to the fires recently experienced there, large deposits of potassium and sodium from burned trees will affect nearby lakes and underground streams.
Acid rinses also lower pH conditions and help to eliminate the yellowing often associated with ultraviolet light and the nitrogen gases from kitchen stoves and gas-powered hot water heaters. Keep this in mind when you encounter mysterious yellowing conditions.
Another area where an acid rinse product can be used is in the removal of urine stains. The concentration needed is rather high, anywhere from 1-to-5 to 1-to-1. This is great for use in large areas. The application is relatively simple: spray the entire floor, let it sit 15 minutes, then extract using your standard method. I believe you will be impressed with how much of the stain is removed.
Understandably, there are some negatives to be found in acid rinses, such as an inability to solubilize certain fats or oils from food stains or other sources, but their removal can be accomplished with a spot remover. There is also some concern as to the inability to remove 100 percent of the residue. However, keep in mind that it is just as impossible to extract 100 percent of the water from the carpet.
Let's examine some of the gains to be had from using acid rinses:
Remember, high heat and reasonable truckmount pressure play an important role when incorporating an acid rinse to remove grease and oil-based soaps. In addition, acid-rinse treatments, when applied by spraying, will leave residues and require extra drying time.
In the near future, you will see more and more information being disseminated on fabric rinsing, or acid neutralizing, especially on the consumer level. Don't be surprised if your next customer asks you whether or not you incorporate this procedure.