Nanomaterials: Surface Functionalization …
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applications [70]. Also [71] oxidized ND was modified with the help of “singlearmed (SA) and double-armed (DA) benzoyl thiourea ligands” and used for adsorption of various metal ions. “Single-armed (ND-SA) nanostructures” have showcased
high adsorption for UO2 (II) compared to “double-armed (ND-DA) nanostructures”
because of medium complexation tendency and strong, flexible spatial configuration. Surface functionalization tends to change the adsorption capacities and surface
charges of NDs. [72] proposed that organic dyes (MB, MO) can have selective
adsorption on thermally oxidized NDs. Compared to MO dye, MB dye shows better
adsorption to the oxidized NDs (ONDs) because of the lesser zeta potential of NDs
with thermal oxidation. The adsorption capability of Cu- PB@DND was higher for
Cs (I), which is positively charged (759 mg/g) because of high surface area and
negative surface charge.
Chen et al. developed a 3D carbon material with the help of two dimensional GO
nanosheets and one-dimensional CNTs oxidized in the adsorption of diethyl phthalate
(DEP), oxytetracycline (OTC), Cd(II), MB, and separating diesel from water [73].
The synergistic effects between GO and CNT in the 3D aerogel structure cause
more adsorption sites, better porosity, larger interspaces, and higher performance
than other graphene aerogels and nanomaterial suspensions of adsorbents. Chen
et al. [74] prepared 3D GS modified with Chitosan (CS) that deliver positive as well
as negatively charged surfaces on the adsorbent, These modified GS successfully
adsorbed dyes and heavy metal through electrostatic attractions and ion complex
formation, respectively, resulted in much higher adsorption capacities.
4.7 Biopolymer Functionalized Carbon-Based
Nanomaterials for Adsorption
Polymers obtained through natural sources such as bacteria, fungi, plants, and
animals, during their growth cycles are called biopolymers. They can be synthesized from biologically sourced substances, including amino acids, proteins, resins,
vegetable oils, and sugars. These biopolymers can be grouped concerning their
origin or monomeric unit. Several studies have proposed biopolymer/carbon-based
nanocomposites’ potential for the separation of pollutants through adsorption. [75]
recently proposed that a syringe dropping technique can be used to develop graphene
nanoplates cross-linked with chitosan spheres (CS/GNPs). This method assists in the
removal of AR1 (cationic) organic and MO (anionic) dyes from polluted water. The
major motivation for the adsorption of dyes onto the CS/GNP surface is the electrostatic interaction between the dye molecules and amino groups protonated in the
chitosan spheres (CS). Dye adsorption was observed to be much efficient at pH lower
than 4 as the protonated amino groups of the CS enhance the process. [76] proposed
a porous 3D nanoarchitecture of Chitosan spheres with a large active surface area
(780 m2/g) and pore volume (0.730 cm3/g), and a 1300 nm average pore diameter,
that enhances the adsorption capacity [77]. Due to p–p interactions between GO
427
applications [70]. Also [71] oxidized ND was modified with the help of “singlearmed (SA) and double-armed (DA) benzoyl thiourea ligands” and used for adsorption of various metal ions. “Single-armed (ND-SA) nanostructures” have showcased
high adsorption for UO2 (II) compared to “double-armed (ND-DA) nanostructures”
because of medium complexation tendency and strong, flexible spatial configuration. Surface functionalization tends to change the adsorption capacities and surface
charges of NDs. [72] proposed that organic dyes (MB, MO) can have selective
adsorption on thermally oxidized NDs. Compared to MO dye, MB dye shows better
adsorption to the oxidized NDs (ONDs) because of the lesser zeta potential of NDs
with thermal oxidation. The adsorption capability of Cu- PB@DND was higher for
Cs (I), which is positively charged (759 mg/g) because of high surface area and
negative surface charge.
Chen et al. developed a 3D carbon material with the help of two dimensional GO
nanosheets and one-dimensional CNTs oxidized in the adsorption of diethyl phthalate
(DEP), oxytetracycline (OTC), Cd(II), MB, and separating diesel from water [73].
The synergistic effects between GO and CNT in the 3D aerogel structure cause
more adsorption sites, better porosity, larger interspaces, and higher performance
than other graphene aerogels and nanomaterial suspensions of adsorbents. Chen
et al. [74] prepared 3D GS modified with Chitosan (CS) that deliver positive as well
as negatively charged surfaces on the adsorbent, These modified GS successfully
adsorbed dyes and heavy metal through electrostatic attractions and ion complex
formation, respectively, resulted in much higher adsorption capacities.
4.7 Biopolymer Functionalized Carbon-Based
Nanomaterials for Adsorption
Polymers obtained through natural sources such as bacteria, fungi, plants, and
animals, during their growth cycles are called biopolymers. They can be synthesized from biologically sourced substances, including amino acids, proteins, resins,
vegetable oils, and sugars. These biopolymers can be grouped concerning their
origin or monomeric unit. Several studies have proposed biopolymer/carbon-based
nanocomposites’ potential for the separation of pollutants through adsorption. [75]
recently proposed that a syringe dropping technique can be used to develop graphene
nanoplates cross-linked with chitosan spheres (CS/GNPs). This method assists in the
removal of AR1 (cationic) organic and MO (anionic) dyes from polluted water. The
major motivation for the adsorption of dyes onto the CS/GNP surface is the electrostatic interaction between the dye molecules and amino groups protonated in the
chitosan spheres (CS). Dye adsorption was observed to be much efficient at pH lower
than 4 as the protonated amino groups of the CS enhance the process. [76] proposed
a porous 3D nanoarchitecture of Chitosan spheres with a large active surface area
(780 m2/g) and pore volume (0.730 cm3/g), and a 1300 nm average pore diameter,
that enhances the adsorption capacity [77]. Due to p–p interactions between GO