THE CHEMISTRY OF CLEANING
Cleaning compounds come in all sizes, colors fragrances, concentrations and
chemical forms. They may be either acidic,
alkaline, neutral
or volatile (solvents)
in nature. Most are intended to be diluted prior to use. Some are specifically
formulated for a single task while others are designed for a wide range of applications.
Selecting
the proper products for stone and masonry surfaces has proven to be
a challenging task for many.
MASONRY VERSUS SYNTHETIC MATERIALS
Synthetic materials are developed in a
controlled and closely regulated environment.
The resulting uniformity of the synthetics mean their care is fairly straight forward and
uncomplicated.
Stone,
however, bears natures’ many complexities and at times unpredictable
characteristics.
COMMON CHARACTERISTICS
Masonry
is a term applied to stone, brick, ceramic tile, terra cotta, and concrete.
All these materials share a two common characteristics, they are absorbent and they
all have pore structures which can catch and hold dirt and soiling debris.
NATURAL ATTRACTION
Stone is composed of a variety
of minerals and these minerals have an inherent ability
to attract like, similar and different
substances to themselves. This attraction varies
depending on the physical characteristics of the substance.
THE SOILING PROCESS
In the
simplest terms in relation to cleaning, dirt/soiling is matter in the wrong place. It
may be classified as inorganic, (containing various minerals), organic, (vegetation, food,
smoke) or a combination of both. It generally has a greater surface area than the surface
it may adhere to.
When
these types of soiling matter are ground-in and or liquefied ( by rain, sprinklers,
the cleaning process ) they can be carried into the pore structure and cracks, accumulate
over time, resulting in staining and a gradual over all color change. They also may
contain
soluble salts that can cause salt
decay.
PRODUCT FORMULATION
The above conditions often make stone and
masonry difficult to clean and maintain.
Conventional hard surface cleaners
contain...surface-active
detergents. These help
penetrate, suspend, emulsify and dissolve surface soiling conditions. They have been
primarily formulated to clean non-porous materials. Using these traditional
cleaners has
shown (as you may have already experienced) not to solve the most common cleaning
problems of stone. In fact, many of these cleaners are the contributing causes to an
unsuccessful stone maintenance program.
Stone
care products have been formulated to
effectively solve specific cleaning problems
related to the porous and mineral characteristics of stone.
Most
stones used today are sensitive to both acidic and alkali cleaners. Acids will burn
many stones. Strong alkalis will cause deterioration and attack the colored minerals,
fading them. This makes the proper selection of chemicals very
important for a
successful stone maintenance program.
THE pH FACTOR
What is pH, and why is it so important when it comes
to a successful stone
care program?
A practical definition of pH is a scale to
determine the acidity or alkalinity of a
aqueous solution.(solvents do not have a pH rating)
The pH scale ranges from 0 - 14 and is divided into three sections.
Beginning with
the Acid range 0 -
6.9, moving into the Neutral range of 7, neither acid nor alkaline,
concluding with the Alkaline
range 7.5 - 14.
The strength of a solution is determined by
where on the pH scale the reading falls.
As a general rule, on the
acid side, the lower the number the stronger the acid and
on the alkaline side, the higher the number the stronger the solution. The pH reading
measures "strength" not quality.
Few realize how rapidly alkalinity is
increased as the pH is raised or how quickly
acidity increases as the pH is lowered. For example, we begin with a solution that
is pH 7 neutral. When the alkalinity of the solution is increased to 8, the strength is
now
10 times stronger than that of pH 7. Increase the pH to 9,
the solution is 100
times
stronger than it was at 7 (10 X10=100). For each
whole step up or down the pH
scale, the strength increases or decreases by 10 times. This rapid buildup continues
until pH 14, which is 10
million times as
strong as pH 7. It is the same for the acid
side of the scale. There is a far greater difference in the concentration of strength
than the values (0-14) indicate.
| pH VALUES |
Acid
0
10 million
1
1,000,000
2
100,00
3
10,000
4
1,000
5
100
6
10
Neutral 7
0
8
10
9
100
10
1,000
11
10,000
12
100,000
13
1,000,000
Alkaline 14
10 million |
We can now
begin to understand why so many floors and surfaces of all types
of materials are damaged by the improper use of strong chemicals and cleaners.
pH CHEMICAL REACTIONS
Many of the
minerals in the different stones are sensitive to acidic and alkaline cleaners.
Take baking soda (alkali) and vinegar
(acid), add a few drops of vinegar to some
baking soda and notice what happens. You'll see an aggressive pH chemical reaction.
You maybe wondering, what does this have to do with stone care?
Stone is composed of chemical compositions in a solidified state; and the use of an
inappropriate cleaning solution on stone may have an immediate chemical reaction,
such as, the use of a acidic cleaner on marble, the acid attacks the calcium (alkali)
resulting in dulling and etching the surface, depending on the strength of the acid; or
the use of a high pH 9 - 10 all-purpose cleaner on a daily basis, this can produce
gradual chemical reactions that can go unnoticed
for some time, resulting in the fading
of the colored minerals in the stone and other more serious deterioration problems.
A word of caution...many conventional products that are labeled
"Neutral" cleaners
can have a pH ranging from 6 - 8. The chemical reactions of these cleaners are
gradual.
Much of the damage caused to stone is the
result of using improper
cleaning
products. It
is not recommended to use "all-purpose" cleaners that list stone as
"one"
of the many things they clean.
Understanding
the pH factor will help in selecting the proper stone "safe"
cleaning
chemicals.
The companies that manufacture natural stone
care products have thoroughly tested
them on all types of stone surfaces to meet expectations and avoid surprises.
STONECARE TECHNIQUES distributes
one of the finest most comprehensible stone
maintenance product lines available...Stone Care International...These products are
USDA approved, environmentally safe and biodegradable. The USDA status ensures
that their products are safe to be used were food will be present without concern of
cross-contamination.
"UNDERSTANDING
STONE AND THE PRODUCTS THAT ARE AVAILABLE
FOR STONE CARE ARE VITAL ELEMENTS FOR A SUCCESSFUL
STONE MAINTENANCE PROGRAM"
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