18.3.3 Polyurethane Composite Materials
Polyurethane-based composite materials manifest superior performance compared
with simple polyurethane-based materials. Such a composite material can be
designed by using different materials having the desired function for targeted
adsorption and photodegradation of pollutants from wastewater. For instance, a
composite of polyurethane and chitosan foams was prepared via the reaction of
polyurethane prepolymer with chitosan in different ratios, as reported by Lee et al.
(Lee et al. 2009). Chitosan has superior performance in the treatment of wastewater,
as its surface possesses plenty of hydroxyl and amine functionalities, which endow it
with improved adsorption capacity of synthetic dyes discharged from textile industries and toxic metallic species through electrostatic interaction or chelating groups.
The shared effect of these types of materials in the composite foams exhibits higher
performance for the adsorption of acid violet 48. The capability of adsorption
improves with the increase in chitosan concentration and reaches a maximum
adsorption of 30 mg/g with 20 weight percent chitosan. Moreover, chemisorption
of acid violet 48 occurs via interaction between its sulfonic ions and protonated
amino groups of chitosan; hence the higher adsorption capacity was observed in
aqueous solution of low pH. A composite foam was developed by Lee et al. to
remove Pb
2+ ions from wastewater. The composite was designed by using
immobilized hydroxyapatite, an inorganic species having higher capacity for the
removal of toxic metallic species, on polyurethane structure (Liao et al. 2010). The
results of the removal tendency of Pb
2+ showed that the composite foams manifested
remarkable performance for Pb
2+ removal at pH 5, and a maximum adsorption
capacity of 150 mg/g was achieved with the composite having 50 wt% hydroxyapatite. Imae et al. fabricated silica/titania composite immobilized polyurethane matrix
for the photodegradation of acid black 1, and excellent performance was observed
under ultraviolet light due to the attachment of a large number of titania
nanoparticles on the polyurethane matrix surface (Mahesh et al. 2014). The developed composite material was found to be stable and exhibited the same performance
until three consecutive duplicate operations. Liu et al. developed a polyurethanebased composite foam via copper films covering followed by oleophilic treatment in
n-dodecanoic acid and silver nitrate alcoholic solution (Zhu et al. 2011). The
fabricated foams having rough and hierarchical structure exhibited
superhydrophobicity and oleophobicity due to the agglomeration of a large number
of Cu–C 11 H 23 COOAg nanoparticles on the polyurethane matrix. These features
allow it to swiftly absorb selective organics from polluted water. Moreover, the
vigorous and compressible characteristics lead to excellent reusability for the separation of oil and water via an easy mechanical squeezing approach. Another research
group demonstrated the fabrication of magnetic polyurethane composite by using
Fe 3 O 4 via dip coating using fluoropolymer aqueous solution. The obtained foam
possesses a hydrophobic surface and is superoleophilic, chemically stable, and
magnetically responsive (Wu et al. 2015). The designed composite foams may be
magnetically driven to adsorb organics from the surface of wastewater with higher
18 Nanomaterials for Textile Waste Treatment
675
Polyurethane-based composite materials manifest superior performance compared
with simple polyurethane-based materials. Such a composite material can be
designed by using different materials having the desired function for targeted
adsorption and photodegradation of pollutants from wastewater. For instance, a
composite of polyurethane and chitosan foams was prepared via the reaction of
polyurethane prepolymer with chitosan in different ratios, as reported by Lee et al.
(Lee et al. 2009). Chitosan has superior performance in the treatment of wastewater,
as its surface possesses plenty of hydroxyl and amine functionalities, which endow it
with improved adsorption capacity of synthetic dyes discharged from textile industries and toxic metallic species through electrostatic interaction or chelating groups.
The shared effect of these types of materials in the composite foams exhibits higher
performance for the adsorption of acid violet 48. The capability of adsorption
improves with the increase in chitosan concentration and reaches a maximum
adsorption of 30 mg/g with 20 weight percent chitosan. Moreover, chemisorption
of acid violet 48 occurs via interaction between its sulfonic ions and protonated
amino groups of chitosan; hence the higher adsorption capacity was observed in
aqueous solution of low pH. A composite foam was developed by Lee et al. to
remove Pb
2+ ions from wastewater. The composite was designed by using
immobilized hydroxyapatite, an inorganic species having higher capacity for the
removal of toxic metallic species, on polyurethane structure (Liao et al. 2010). The
results of the removal tendency of Pb
2+ showed that the composite foams manifested
remarkable performance for Pb
2+ removal at pH 5, and a maximum adsorption
capacity of 150 mg/g was achieved with the composite having 50 wt% hydroxyapatite. Imae et al. fabricated silica/titania composite immobilized polyurethane matrix
for the photodegradation of acid black 1, and excellent performance was observed
under ultraviolet light due to the attachment of a large number of titania
nanoparticles on the polyurethane matrix surface (Mahesh et al. 2014). The developed composite material was found to be stable and exhibited the same performance
until three consecutive duplicate operations. Liu et al. developed a polyurethanebased composite foam via copper films covering followed by oleophilic treatment in
n-dodecanoic acid and silver nitrate alcoholic solution (Zhu et al. 2011). The
fabricated foams having rough and hierarchical structure exhibited
superhydrophobicity and oleophobicity due to the agglomeration of a large number
of Cu–C 11 H 23 COOAg nanoparticles on the polyurethane matrix. These features
allow it to swiftly absorb selective organics from polluted water. Moreover, the
vigorous and compressible characteristics lead to excellent reusability for the separation of oil and water via an easy mechanical squeezing approach. Another research
group demonstrated the fabrication of magnetic polyurethane composite by using
Fe 3 O 4 via dip coating using fluoropolymer aqueous solution. The obtained foam
possesses a hydrophobic surface and is superoleophilic, chemically stable, and
magnetically responsive (Wu et al. 2015). The designed composite foams may be
magnetically driven to adsorb organics from the surface of wastewater with higher
18 Nanomaterials for Textile Waste Treatment
675