Different morphologies of carbon nanotubes effect on the lead removal from aqueous solution

Abstract

Four kinds of CNTs with different morphologies were produced by chemical vapour deposition method. After oxidation with nitric acid, their specific surface area, particle size distribution and functional groups on the surfaces were characterized. Adsorption isothermal experiment shows that the CNTs with more defects, which can be easily introduced more functional groups on their surfaces prepared at 650 -C, have higher lead adsorption capability from aqueous solution and are promising adsorbents in wastewater treatment. D

Carbon nanotube membranes with ultrahigh specific adsorption capacity for water desalination and purification

“…In addition, with a small (B10 nm) UCNT diameter, their modified outer layers are easily accessible to the solution. Consequently, a high salt adsorption capability was achieved with the modified UCNTs when salt water flowed through the porous structure 35,36 . It is worth mentioning that samples ii-iv could completely remove salt below the detection threshold of 10 -7 M from the solution in the first round of the filtration process (shown in Fig.…”

Potential of carbon nanomaterials for removal of heavy metals from water

“…A lead sorption study with CNTs was carried out by Li et al [20] at pH 7 and equilibrium concentration range of 10-80 μeq/L where the sorption capacity was reported as 482 μeq/g. In another study, Li et al [24] reported that the lead sorption capacity of CNTs at pH 5 was 797 μeq/g. The lead sorption capacity on NPC is significantly higher (2000 μeq/g) than on these CNTs.…”

“…CNTs were found to be superior sorbents for inorganic pollutants such as fluoride [18], and several divalent metal ions [7,8,[19][20][21][22][23][24][25]. Li et al [24] reported that CNTs with more defects and poor quality possess higher surface area and exhibit better lead sorption capacity compared to aligned CNTs. Activation of CNTs plays an important role in enhancing the maximum sorption capacity.…”

“…Maximum sorption capacity for heavy metals determined based on Langmuir model varies based on the type of metal. The maximum sorption capacity for cadmium, lead, nickel and zinc is reported to be in the range of 10-11 mg/g [21], 49-97 mg/g [20,22,24], 9-47 mg/g [19,25] and 11-43 mg/g [7,8], respectively. Hence, with CNTs as sorbent, metal ion uptake followed the order Pb 2+ > Ni 2+ > Zn 2+ > Cd 2+ .…”

“…Activation of CNTs under oxidizing conditions with chemicals such as HNO 3 , KMnO 4 , H 2 O 2 , NaOCl, H 2 SO 4 , KOH, and NaOH have been widely reported [8,21,26,27]. During activation, the metallic impurities and catalyst support materials are dissolved and the surface characteristics are altered due to the introduction of new functional groups [24,26].…”