Solid-liquid separations with a temperature-responsive polymeric flocculant: Effect of temperature and molecular weight on polymer adsorption and deposition

Abstract

The effects of temperature and molecular weight of the temperature-responsive polymer, poly(N-isopropylacrylamide) (PNIPAM) were investigated in the solid-liquid separation of silica and alumina mineral particles. Suspensions dosed with PNIPAM at 25°C were stable and did not settle. When the temperature was raised above the polymer lower critical solution temperature (LCST) (>32°C), the suspensions were found to have high settling rates, large particle aggregate sizes and high suspension shear yield stresses (τy). The sediment bed solids volume fraction (φf), of these suspensions was found to increase after a temperature decrease below the polymer LCST and was attributed to a decrease in the..