ENTHALPY OF ADSORPTION AND ADSORPTION-ISOTHERMS OF POLYACRYLAMIDE ON SEA SAND

The enthalpy of dilution of polyacrylamide 3530s (HPAM) solution, the enthalpy of adsorption of the polymer on sea sand, and the adsorption isotherms, were determined at 298.15 K. The effect of NaCl on these properties were also determined. From the experimental results and certain assumptions, it was deduced that, for an adsorbed HPAM molecule, a large number of segments are in contact with the surface of the solid, some of them forming hydrogen-bonds, most of them belonging to Van der Waals interactions, which are much weaker than hydrogen-bonds, and the HPAM molecules adsorbed on the surface of the solid are spread out.