Ligand-exchange mechanism: new insight into solid-phase extraction of uranium based on a combined experimental and theoretical study

2015 ◽  
Vol 17 (11) ◽  
pp. 7214-7223 ◽  
Author(s):  
Yin Tian ◽  
Jia Fu ◽  
Yi Zhang ◽  
Kecheng Cao ◽  
Chiyao Bai ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Ligand Exchange ◽  
Theoretical Study ◽  
Solid Phase ◽  
Exchange Process ◽  
Water Molecules ◽  
Phase Extraction ◽  
Extraction Mechanism ◽  
Coordinated Water ◽  
Insight Into

The extraction mechanism is an exchange process between the ligands on Urea-GO and the coordinated water molecules of uranyl.

scholarly journals The Nature of Rest Silanol Groups on the Surfaces of Silica Based Solid Phase Extraction Materials

2013 ◽  
Vol 650 ◽  
pp. 66-71 ◽  
Author(s):  
Alfred A. Christy
Keyword(s):  
Infrared Spectroscopy ◽  
Solid Phase Extraction ◽  
Silica Gel ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Solid Phase ◽  
Water Molecules ◽  
Phase Extraction ◽  
Modified Silica Gel ◽  
Silanol Groups

Chemically bonded solid phase materials are very important in separation chemistry. The chemically modified silica gel contains rest silanol groups that can affect the retention properties when they are used for separation of compounds. Some commercially available solid phase extraction (SPE) materials based on silica gel were analysed for rest silanol groups by near infrared spectroscopy. The combination frequency of the water molecules in the 5500- 5000 cm -1 region was used in identifying the nature of water molecules on the surface and the information was used to identify the types of silanol groups on the surface. Second derivative technique was employed in the detailed analysis. Nine different SPE materials including C18, C8, C6H5, NH2, OH, CN, SiOH, SA (SCX) and SB (SAX) were examined by near infrared spectroscopy for rest silanol groups. The results show that the non-polar and polar stationary phases contain vicinal silanol groups and the ion exchange solid phase materials contain free, vicinal and geminal silanol groups.

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