better and the so-called flocculation window is broader, as in the case of charge
neutralization.
The removal of dye was also investigated [127]. PECs, described as “new particle
forming flocculants”, were used in comparison with PCs to separate dyes from sludge
(mixture of organic and inorganic components). The charge of the system to be
flocculated was shown to be the most important property for influencing flocculation
behavior. Therefore, sludge with strong anionic charge could be separated with
commercial PC according to a patch mechanism, whereas for the removal of nearly
“uncharged” sludge or dye the complex particles were more effective. The latter can be
easily tailored with different properties by the interaction between aqueous solutions
of dodecylamidoethyl-dimethylbencyl-ammonium chloride (Quartolan), which carries a positive charge, and a PA such as PSS. In dependence on the mixing ratio nÀ/n+
as well as on the dosage, these complexes can effectively eliminate commercial dyes
such as Acid Yellow 3 or Acid Blue 74 due to their hydrophobicity and structure.
PSCs can be also used as flocculants in montmorrilonite dispersions [128]. An
anionic surfactant (SDS) was combined with a cationic polymer (PDADMAC). At a
1:1 molar ratio, optimal flocculation was obtained owing to the formation of an
insoluble surfactant–polymer complex in the presence of particles. Such interactions
may lead to a flocculation mechanism that combines polymer adsorption, charge
neutralization, and hydrophobic interactions. Other experiments have shown that a
similar flocculation process can be achieved by using a cationic surfactant and
anionic polymer [127].
4.5 Removal of Organic Pollutants
Buchhammer [129] described the design of new materials for removing organic
pollutants such as p-nitrophenol or dyes from wastewater. The sorption of solved
organic molecules on previously formed PSCs or PECs (PC/PA) was studied. The
scheme of complex formation and possible structures is presented in Fig. 14. The
sorption capability of such macromolecular assemblies increases with increasing
molar mass and hydrophobicity of the macromolecules used.
The solubilization of hydrophobic molecules such as pyrene (a fluorescence
probe), or Nile Red (a solvatochromic probe) in nanoparticles was investigated by
Nizri et al. [130]. They studied the morphology of the resulting nanoparticles and
their ability to solubilize hydrophobic materials. As shown by AFM and SEM
imaging, the particles are spherical, having a diameter of about 20 nm. From pyrene
solubilization it appeared that the hydrophobicity of the nanoparticles depends on
the ratio between SDS molecules and the charge unit of the polymer and therefore
they confirmed the results described by other authors [128].
Polyelectrolyte Complexes in Flocculation Applications
55
neutralization.
The removal of dye was also investigated [127]. PECs, described as “new particle
forming flocculants”, were used in comparison with PCs to separate dyes from sludge
(mixture of organic and inorganic components). The charge of the system to be
flocculated was shown to be the most important property for influencing flocculation
behavior. Therefore, sludge with strong anionic charge could be separated with
commercial PC according to a patch mechanism, whereas for the removal of nearly
“uncharged” sludge or dye the complex particles were more effective. The latter can be
easily tailored with different properties by the interaction between aqueous solutions
of dodecylamidoethyl-dimethylbencyl-ammonium chloride (Quartolan), which carries a positive charge, and a PA such as PSS. In dependence on the mixing ratio nÀ/n+
as well as on the dosage, these complexes can effectively eliminate commercial dyes
such as Acid Yellow 3 or Acid Blue 74 due to their hydrophobicity and structure.
PSCs can be also used as flocculants in montmorrilonite dispersions [128]. An
anionic surfactant (SDS) was combined with a cationic polymer (PDADMAC). At a
1:1 molar ratio, optimal flocculation was obtained owing to the formation of an
insoluble surfactant–polymer complex in the presence of particles. Such interactions
may lead to a flocculation mechanism that combines polymer adsorption, charge
neutralization, and hydrophobic interactions. Other experiments have shown that a
similar flocculation process can be achieved by using a cationic surfactant and
anionic polymer [127].
4.5 Removal of Organic Pollutants
Buchhammer [129] described the design of new materials for removing organic
pollutants such as p-nitrophenol or dyes from wastewater. The sorption of solved
organic molecules on previously formed PSCs or PECs (PC/PA) was studied. The
scheme of complex formation and possible structures is presented in Fig. 14. The
sorption capability of such macromolecular assemblies increases with increasing
molar mass and hydrophobicity of the macromolecules used.
The solubilization of hydrophobic molecules such as pyrene (a fluorescence
probe), or Nile Red (a solvatochromic probe) in nanoparticles was investigated by
Nizri et al. [130]. They studied the morphology of the resulting nanoparticles and
their ability to solubilize hydrophobic materials. As shown by AFM and SEM
imaging, the particles are spherical, having a diameter of about 20 nm. From pyrene
solubilization it appeared that the hydrophobicity of the nanoparticles depends on
the ratio between SDS molecules and the charge unit of the polymer and therefore
they confirmed the results described by other authors [128].
Polyelectrolyte Complexes in Flocculation Applications
55