Flocculation Mechanism of Suspended Particles Using the Hydrophilic/Hydrophobic Transition of a Thermosensitive Polymerx [Translated]^†

Abstract

We examined the f locculation of suspended particles using a thermosensitive polymer which undergoes a reversible hydrophilic/hydrophobic transition when heating or cooling its aqueous solution. As a thermosensitive polymer poly (N-isopropylacrylamide)

Compaction of TiO2 suspension utilizing hydrophilic/hydrophobic transition of cationic thermosensitive polymers

“…It is important to note that because the hydrophilic/hydrophobic transition of thermosensitive polymer is reversible, the flocs disorganize and return to the stable suspended particles upon cooling below the transition temperature of the polymer. The compaction mech- anism shown here was confirmed using poly(NIPAM) and kaolin suspension [2,3].…”

“…In an effort to alleviate this problem, the authors proposed a novel flocculation/compaction method using thermosensitive polymers [2,3]. Thermo-sensitive polymers are soluble in water at low temperature, but are insoluble above the intrinsic transition temperature of the polymer [4,5].…”

“…On the other hand, we previously reported [2] that in a highly concentrated kaolin suspension, compacted kaolin sludge was easily obtained upon the hydrophilic/hydrophobic transition of poly(NIPAM). The concept describing the compaction mechanism involves the hydrophobic interaction, which is described in Section 2 [3].…”

“…Fig. 1 shows a schematic representation of the compaction mechanism of suspended particles involving the hydrophobic interaction of thermosensitive polymers proposed by the authors [3]. First, by mixing the suspended particles with the thermosensitive polymer below the transition temperature of the polymer, the surface of the suspended particles is sufficiently covered with the adsorbed polymer molecules.…”

Temperature controlled surface hydrophobicity and interaction forces induced by poly (N-isopropylacrylamide)

“…The ability of PNIPAM to undergo controlled transitions from hydrophobic to highly hydrophilic has sparked considerable interest in its suitability as a surface modification reagent in minerals processing. A large number of studies have found PNIPAM to be a highly successful agent for facilitating mineral aggregation and consolidation [9][10][11][12][13][14][15], however questions remain regarding PNIPAM-induced aggregation mechanisms. In typical settling operations, flocculation occurs as a result of polymer bridging between mineral particles, which causes them to form aggregates [16].…”