Synthetic Polymers for Potable, Cooling
and Boiler Water Treatment
Water soluble polymers are used primarily to disperse, suspend or stabilize
particulate matter in water. There are three basic categories of water soluble
Synthetic, which are produced by polymerization of petroleum or natural gas
Semi-synthetic (sometimes called organic polymers), manufactured from natural
organic or microbial materials, using chemical or fermentation techniques.
Natural, including plant and animal materials such as lignin, tannins and
sugars. (See Method Summary #68, Natural Organic Matter).
All water soluble polymers perform similar functions, but synthetic polymers
are preferred in many applications because of their greater efficiency and
Synthetic polymers include polyacrylates, polymethacrylates, polymaliecs,
polystyrenes and sulfonated polystyrenes. (Organic phosphonates are considered
to be a separate category of corrosion inhibitors and are addressed in a separate
ChemScan Application Summary). Manufacturers of synthetic polymers include
BASF, B F Goodrich, Celanese, Cytec, Ciba, Dow/Hampshire, FMC, Johnston, Nippon
Shokubai, Rohm & Haas, Stockhausen and others.
Standard Analysis Techniques
Standard free polymer analysis techniques available to the water treatment
industry include the ferric complexation method and the quaternary surfactant
turbidity method. The ferric complexation method adds a surplus concentration
of dissolved iron into the sample for reaction with free polymer. The remaining
dissolved iron is measured and the free polymer concentration is calculated
from the result. The quaternary surfactant turbidity test is used for analysis
of anionic polymers by measuring the turbidity caused by introduction of a
cationic compound (typically Hyamine®) into the sample.
Several methods are also available to measure tags or tracer compounds that
are either attached to the polymer or introduced as a proportionate component
of the water treatment product formulation. These tracers may require proprietary
detection systems and may concentrate in recirculating water systems in a
manner that is not proportionate to the available fraction of active treatment
ChemScan Analysis Method
Synthetic (and some semi-synthetic) polymers tend to have unique absorbance
signatures in the ultraviolet wavelength range. In pure media and in high concentration,
many polymers would be good candidates for primary analysis, (without reagents)
using ChemScan. In typical recirculating cooling water and boiler blow-down,
however, the concentration of free polymer is relatively small compared to
other dissolved chemicals and particulates in the sample. Therefore, direct
analysis using uv absorbance may not be possible for these applications.
ChemScan has developed automated secondary methods for polymer analysis based
on the two most common analysis techniques used by the water treatment industry.
The ChemScan ferric complex method establishes a baseline in the sample to
eliminate interference from any dissolved minerals, complexed polymer or background
turbidity prior to introduction of ferric reagent. The ChemScan quaternary
surfactant turbidity test also starts with a baseline adjustment for background
turbidity, prior to introduction of the quaternary compound.
Either of the ChemScan methods are suitable for analysis of the so called “tagged” polymers,
although, it is the polymeric reactions that are measured, not the tag itself.
ChemScan can also detect other water treatment components typically used as
tracers. Such products include tolytriazole (see Method Summary #120) and sodium
molybdate (see Method Summary #123). Full uv spectrum analysis assures stable,
accurate results for either method.
Free polymer can be detected as a stand
alone parameter or can be detected as one of a suite of parameters by a multiple
parameter ChemScan analyzer.
ChemScan analyzers can also monitor single or multiple sample points, depending
on the specific model selected for the application. Results can be output
in serial or analog (4-20 mA) format as either ppm of the specific treatment
chemical or as ppm of equivalent product concentration.