USDA-ARS perspective on PAM

Lentz, R.D. (2009) USDA-ARS perspective on PAM. pp. 3-5. In: Susfalk, R. (ed.) PAM and PAM Alternatives Workshop. USA-NV-Reno, 2008/02/26-27. Desert Research Institute, Reno, NV.

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Abstract

Polyacrylamide (PAM) is a synthetic organic polymer derived from petroleum. It is an
industrial flocculent used worldwide in several industries. For example, one
international manufacturer of PAM markets 31 percent of its PAM product to the
municipal potable and waste water treatment industry, 18 percent to paper production,
17 percent to industrial water treatment, 13 percent to oil production (enhanced oil
recovery), 9 percent to mining, and the remaining 8 percent to agriculture, animal feed,
and cosmetic industries. Since agriculture is a relatively small market, the polymer
manufacturers commit only limited resources toward developing or improving
agricultural polymer products. This is why the research conducted by the U.S.
Department of Agriculture, Agricultural Research Service (USDA-ARS) and others
toward developing PAM technologies has been crucial to growing its potential and useful application in irrigated
agriculture. The PAM used in furrow irrigation erosion control is a water soluble, anionic, high molecular weight,
12 to 15 Mg mol-1
(i.e., >150,000 repeating units) polymer with moderate charge density (~18 % of the repeating
units are negatively charged). This PAM is also referred to as water soluble PAM (WSPAM) or linear anionic
PAM (LAPAM). This long, single-chain polymer can be dissolved in water, where it forms a hydrated random coil
structure. The size of the PAM hydrated coil increases with increasing molecular weight and charge density, and
decreasing salt concentration in the water. Loops and tails of the hydrated polymer extend out into the water.
Negatively charged sites on the polymer form electrostatic bonds with negatively charged sites on soil particles
through intervening positively charged cations, Ca2+, Mg2+, and others. Thus, the polymer can bind soil particles
together via a so-called cationic bridge, which is one of the main mechanisms by which PAM interacts with soil.

Item Type:	Conference or Workshop Item (Paper)
NWISRL Publication Number:	1292
Subjects:	Polyacrylamide (PAM) > Water-soluble PAM (WSPAM) > Percolation water Polyacrylamide (PAM) > Water-soluble PAM (WSPAM) > Application Strategies Polyacrylamide (PAM) > Water-soluble PAM (WSPAM) > Runoff Polyacrylamide (PAM) > Water-soluble PAM (WSPAM)
Depositing User:	Users 6 not found.
Date Deposited:	17 Apr 2009 16:37
Last Modified:	18 Oct 2016 15:08
Item ID:	1315
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1315