Determination of very low concentrations of polyacrylamide and polyethyleneoxide flocculants by nephelometry

Abstract

A method is described for the analytical determination of low concentrations of polyacrylamide or polyethyleneoxide flocculants in water, in the range 0–10 parts/106. It depends on measuring the turbidity produced by mixing the polymer solution with a dilute solution of tannic acid in the presence of 1 m NaCl. With a sensitive nephelometer, as little as 0.1 parts/106 of flocculant can be detected.

PEO Flocculation with Phenolic Microparticles

“…Each cycle contained 20 runs (scans). PEO adsorption isotherms were measured using the tannic acid method (7,10,11). A linear calibration equation relating the absorbency of the PEO/tannic acid complex as a function of the PEO concentration was obtained with an HP8452A UV-vis spectrophotometer (Hewlett-Packard) at a wavelength of 600 nm.…”

Study of the interaction between poly(ethylene oxide) and phenol-formaldehyde resin

“…Colloidal PFR was found to pass through the screen in the drainage jar. PEO concentration was measured using tannic acid reagent [15] and measuring the transmission of the samples at 450, 500, 550 and 600 nm. Most experiments were carried out at two levels of polymer addition.…”

Measuring poly(acrylamide) flocculants in fresh water using inter-polymer complex formation

“…Turbidometric analysis is possible if the polyacrylamide is hydrolysed with a quaternary ammonium cation achieve detection at low concentrations it is necessary to pass the solution through a cation exchange resin following alkaline hydrolysis, which is then evaporated and subsequently collected in order to reveal concentrations lower than 1 mg l -1 13 . This methodology has been automated to give accurate concentrations as low as 5 mg l -1 , although the process can be affected by anions (such as alkylbenzene sulfonates and large fatty acids) 27 and it is not suitable for non-anionic forms of acrylamide without additional precipitation by tannic acid 9 . With all of these steps in place turbidometric measuring techniques were found to be accurate and reproducible to 1% at concentrations as low as 0.1 mg l -1 .…”

“…In the EU alone approximately 50,000 tonnes of poly(acrylamide) are used per annum for effluent treatment, and the polymer also finds commercial uses in paper, pulp, mineral and crude oil processing, coating applications and soil/sand treatment 2 . Due to its high usage, concerns regarding the release of the free monomer acrylamide (known to be highly toxic 3 ) and concerns over the toxicity of anionic/cationic polymers to aquatic lifeforms [4][5][6] , researchers have long been attempting to find new methods to determine the fate of the polymer after use [7][8][9][10][11][12][13][14][15][16] . In practice the intrinsic toxicity of the polymer released to the environment is reduced by many factors 17,18 so whilst these polyelectrolytes are not a priority for environmental control, our inability to trace these synthetic polymers and determine their spread through surface waters is a severe limiting factor to their future use.…”