Linear β-Cyclodextrin Polymer Functionalized Multiwalled Carbon Nanotubes as Nanoadsorbent for Highly Effective Removal of U(VI) from Aqueous Solution Based on Inner-Sphere Surface Complexation

Abstract

Linear β-cyclodextrin polymer functionalized multiwalled carbon nanotubes (MWCNTs-CDP) were synthesized and employed as a novel nanoadsorbent to remove uranyl ions in wastewater solutions. The characterization of MWCNTs-CDP, with Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer−Emmett−Teller (BET), suggested that the CDP was successfully modified on the MWCNTs surfaces. The removal efficiency of uranyl ions in aqueous solution by MWCNTs-CDP was investigated via varying various experimental conditions. We found that the removal of uranyl ions correlated with both pH and temperature, and the optimum pH and temperature were 6.0 and 323.15 K, respectively. The adsorption of uranyl ions was very fleet at the initial 1 h and then reached the adsorption equilibrium after 3 h. The data from the adsorption dynamics experiment could be commendably fitted by the pseudo-second-order model (R 2 > 0.982), suggesting that chemisorption might be the rate-controlling mechanism. The Langmuir model (R 2 > 0.995) manifested that the maximum adsorption capacity of uranyl ions on MWCNTs-CDP was boosted from 66.16 to 89.54 mg g −1 upon the change of temperature from 293.15 to 323.15 K. This result was better than that of some reported adsorbents. The thermodynamics analysis proved that the adsorption of uranyl ions on MWCNTs-CDP was a spontaneous process and an endothermic one. The adsorption mechanism of uranyl ions on MWCNTs-CDP was verified to be dominated by inner-sphere surface complexation. Our results indicated that MWCNTs-CDP can be utilized as a novel nanoadsorbent for highly effective removal of uranyl ions in actual uranylbearing effluents.

An amyloid-like proteinaceous adsorbent for uranium extraction from aqueous medium

“…46,47 Accordingly, many b-CD based adsorbents have been of great interest and developed. [48][49][50] The relatively good water solubility of b-CD certainly limits its application in metal extraction as an adsorbent individually; thus, b-CD must be combined with water insoluble carriers, including carbon nanotubes, graphene oxide, graphene aerogel, graphite carbon nitrogen (g-C 3 N 4 ), PAN membranes, magnetic iron oxide, Al(OH) 3 , titanium dioxide, montmorillonite and so on, 46,47,[51][52][53][54][55][56][57][58][59][60] with the aim to isolate metal loaded adsorbents from solution. Even though these b-CD based adsorbents present good adsorption capacity and selectivity for uranium ions, the preparation process is complicated, and toxic organic reagents are oen required; besides, water insoluble carriers are costly, nonrenewable and nondegradable.…”

Multifunctional β-Cyclodextrin Polymer for Simultaneous and Effective Removal of Organic Micropollutants, Heavy Metals, and Detrimental Microorganisms from Water

“…β-Cyclodextrin (CD), derived from starch, is a renewable resource and nontoxic to human health. β-Cyclodextrin polymers have attracted great attention owing to their structural properties of a hydrophilic outer liner and a special hydrophobic cavity. − Recently, a few porous β-CD polymers with relatively high specific surface areas (80–200 m 2 /g) have been successfully synthesized using fossil-derived material, tetrafluoroterephthalonitrile (TFTPN), as a cross-linker to introduce a rigid benzene ring into CD polymers. ,− Clearly, compared with the TFTPN, the compound of gallic acid (GA) presents several advantages. First, as a compound of plant polyphenol, GA is renewable and cost-effective.…”

Efficient electrosorption of uranyl ions by a homemade amidoxime‐modified carbon paper‐based electrode in acidic aqueous condition

“…However, each method has its drawbacks: the byproducts generated from precipitation method need secondary treatment 13 ; ion exchange is not suitable for high salinity solution 14 ; organic phase in solution extraction will cause secondary pollution 15 ; and bioremediation method is quite sensitive to the surroundings 16 . Among them, adsorption is considered a better choice because of its cost‐effectiveness; however, the conventional physical adsorption is limited by low UO 2 2+ removal efficiency and difficult UO 2 2+ recovery 17,18 . In recent years, electrosorption has become a promising method for UO 2 2+ removal from water.…”

“…16 Among them, adsorption is considered a better choice because of its cost-effectiveness; however, the conventional physical adsorption is limited by low UO 2 2+ removal efficiency and difficult UO 2 2+ recovery. 17,18 In recent years, electrosorption has become a promising method for UO 2 2+ removal from water. This method allows a high adsorption capacity and the electrodes can be conveniently regenerated after treatment.…”