An Infrared Study of a Polyacrylate Flocculant Adsorbed on Hematite

Abstract

Hematite was flocculated at various pH values using a 100% polyacrylate of high molecular weight, and the adsorbed configuration of the polymer was determined from infrared (DRIFT) spectra. The positions of the symmetric and asymmetric carboxylate stretches for the polyacrylate sodium salt and the adsorbed flocculant, and their separation were used to determine the adsorbed configuration. The adsorption mechanism is dominated by chemisorption, except at neutral pH in the presence of calcium ions when electrostatic interactions also play a role. At pH 7 the polyacrylate adsorbs in an essentially monodentate configuration. At this pH there is a significant degree of hydrogen bonding between the CO group of the flocculant and either the surface hydrogens of the hydroxylated hematite or the solvent (water). At higher pH (11−14) the monodentate configuration is much less evident and an asymmetric bidentate bridging structure is formed. In the presence of calcium ions at pH 7 a bidentate chelating structure occurs in addition to the monodentate structure. This chelating structure was not found at pH 13 and 14.

Degradation of γ-Hexachlorocyclohexane Using Carboxymethylcellulose-Stabilized Fe/Ni Nanoparticles

“…In the present work, Δν was 311 cm −1 (1622 to1311 cm −1 ), indicating that monodentate interaction was the key fashion. Analogous results were observed in other research (Jones et al 1998;). …”

Synthesis and characteristics of poly(3-pyrrol-1-ylpropanoic acid) (PPyAA)–Fe3O4 nanocomposite

“…For both PPyAA and nanocomposite, the intense peak at 1700 cm −1 was derived from the existence of the C O stretching band [30,31]. On the basis, as was argued by Bronswijk et al [32,33], when the carboxylate group is directly involved in adsorption it is possible to discriminate between monodentate, bidentate chelating, and bidentate bridging structures. In the monodentate structure, the higher of the two carboxylate frequencies occurs at around 1680 cm −1 and is indicative of significant C O character.…”

Spectroscopic investigation of the adsorption mechanisms of polyacrylamide polymers onto iron oxide particles

“…have proven significantly difficult to dewater to a high solid loading (>60 wt% solid) via coagulation and flocculation [4,7,8,[11][12][13][14][15][16][17]. Understanding the polymeric flocculant adsorption behavior and subsequent flocculation will enable the dewatering process to be optimized.…”