Adsorption of U(VI) on nonthermal plasma-modified carbon nanotubes

Abstract

Surface characteristics of modified carbon nanotubes and its application in lead adsorption from aqueous solution

NH3 Plasma Functionalization of UiO-66-NH2 for Highly Enhanced Selective Fluorescence Detection of U(VI) in Water

“…Generally, the mechanisms of fluorescence quenching include dynamic quenching and static quenching, which are mainly caused by physical collision-induced energy transfer and adsorption-induced coordination that affect electronic transmission, respectively . It is well known that U­(VI) shows a strong selective affinity for amine groups. ,, In our experiment, the majority of the U­(VI) species exist in the form of UO 2 2+ , UO 2 OH + , UO 2 (OH) 2 , and (UO 2 ) 3 (OH) 5 + , which can be adsorbed on the probe through hydrogen bonding. Therefore, the fluorescence quenching effect induced by U­(VI) is deduced to be a static quenching mechanism caused by the adsorption of U­(VI).…”

“…66 It is well known that U(VI) shows a strong selective affinity for amine groups. 47,67,68 In our experiment, the majority of the U(VI) species exist in the form of UO 2 2+ , UO 2 OH + , UO 2 (OH) 2 , and (UO 2 ) 3 (OH) 5 + , which can be adsorbed on the probe through hydrogen bonding. Therefore, the fluorescence quenching effect induced by U(VI) is deduced to be a static quenching mechanism caused by the adsorption of U(VI).…”

“…When the pH value was increased to 6, the existing states included UO 2 2+ , UO 2 OH + , UO 2 (OH) 2 , and (UO 2 ) 3 (OH) 5 + . A further increase in the pH value (pH > 7) leads to a gradual precipitation of U­(VI) and change of free UO 2 2+ to a polynuclear hydroxide complex. , As a result, pH 6.0 is appropriate and chosen for further sensing experiments on the basis of fairly strong fluorescence emission (Figure d) while maintaining the soluble state U­(VI) in water.…”

“…For example, Li et al reported NH 3 /Ar plasma-modified MWCNTs with better adsorption performance for U(VI) due to amine group functionalization. 47 An Fe-MOF was modified by low-temperature plasma technology for efficient organic pollutant removal. 48 In addition, a Ni-based metal organic framework has been plasma modified for electrochemical hydrogen evolution.…”

“…Some studies reported surface modification using plasma functionalization technology. For example, Li et al reported NH 3 /Ar plasma-modified MWCNTs with better adsorption performance for U­(VI) due to amine group functionalization . An Fe-MOF was modified by low-temperature plasma technology for efficient organic pollutant removal .…”