Nitrogen-Doped Nanoporous Carbon Nanospheroids for Selective Dye Adsorption and Pb(II) Ion Removal from Waste Water

Abstract

In the presence of melamine and block copolymers, namely, F108, F127, and P123, nitrogen-doped nanoporous carbon nanospheroids (N@CNSs) were synthesized by the hydrothermal process. The F127-modified sample (CNF127) exhibits the maximum Brunauer–Emmett–Teller (BET) surface area of 773.4 m 2 /g with a pore volume of 0.877 cm 3 /g. The microstructural study reveals that nanospheroids of size 50–200 nm were aggregated together to form a chainlike structure for all triblock copolymer-modified samples. The X-ray photoelectron spectroscopy study shows the binding energies of 398.33 and 400.7 eV attributed to sp 2 (C–N=C)- and sp 3 (C–N)-hybridized nitrogen-bonded carbons, respectively. The synthesized N@CNS samples showed selective adsorption of organic dye methylene blue (MB) in the presence of methyl orange (MO) as well as Pb(II) ion removal from contaminated water. The adsorptions for MB and Pb(II) ions followed pseudo-first-order and pseudo-second-order kinetic models, respectively. The sample CNF127 showed the highest adsorption of 73 and 99.82 mg/g for MB and Pb(II) adsorptions, respectively. The adsorption capacity for MB of the copolymer-modified samples follows the order CNF127 > CNP123 > CNF108, which corroborated with the mesoporosity as well as nitrogen content of the corresponding samples. The maximum % adsorption of Pb(II) follows the order CNF127 (99.82%) > CNF108 (98.74%) > CNP123 (91.82%), and this trend is attributed to the BET surface area of the corresponding samples. This study demonstrates multicomponent removal of water pollutants, both organic dyes and inorganic toxic metal ions.

Hydrothermal Fabrication of Fe3O4@Carbonaceous Microspheres for Efficient Removal of Oil and Metal Ions from the Aqueous Phase

“…On the other hand, the sp 3 -hybridized nitrogen element affords adequate lone pair electrons to form the complex compound structure with transition-metal ions such as Cu 2+ and Ni 2+ . Also, this mechanism could also explain why amino-Fe 3 O 4 @C- x -O samples have higher adsorption capacity toward transition-metal ions than other metallic ions. , …”

Facile Fabrication of a Low-Cost Alginate-Polyacrylamide Composite Aerogel for the Highly Efficient Removal of Lead Ions

“…However, when the concentration of Pb 2+ exceeds 50 mM, the adsorption capacity of Alg-PAM remains stable and shows no further increase. Therefore, the maximum adsorption capacity of Alg-PAM for Pb 2+ is 252.2 mg/g, which is higher than that of most of the reported Pb 2+ sorbents (Table 2) [28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Preparation and Pb (II) adsorption in aqueous of 2D/2D g‐C3N4/MnO2 composite

“…[34] The positive values of ΔS 0 indicated that the randomness increased at the solid/liquid interface. [45] NiFe 2 O 4 /MnO 2 nanocomposites 85.78 [46] PVC/α-MnO 2 -KH550 NC 5% wt% 100 [14] Manganese-oxide/biochar 91.98 [47] Fe 3 O 4 -g-C 3 N 4 189.36 [48] S 3.9% -g-C 3 N 4 52.63 [49] CNF 127 99.82 [50] Sugar cane biochar 86.96 [51] Graphene oxide-starch 108.68 [52] g-C 3 N 4 65.6 [53] g-C 3 N 4 /β-CD 100.5 [54] These results demonstrated that the adsorption process of Pb (II) onto g-C 3 N 4 /MnO 2 was spontaneous and endothermic.…”