Selective removal of 2,4-dichlorophenoxyacetic acid from water bymolecularly-imprinted amino-functionalized silica gel sorbent
Deman Han , Wenping Jia , Huading Liang
DOI:
Received May 10, 2009,Revised July 14, 2009, Accepted , Available online
Volume 22,2010,Pages 237-241
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A molecularly-imprinted amino-functionalized sorbent for selective removal of 2,4-dichlorophenoxyacetic acid (2,4-D) was prepared
by a surface imprinting technique in combination with a sol-gel process. The 2,4-D-imprinted amino-functionalized silica sorbent was
characterized by FT-IR, nitrogen adsorption and static adsorption experiments. The selectivity of the sorbent was investigated by a batch
competitive binding experiment using an aqueous 2,4-D and 2,4-dichlorophenol (2,4-DCP) mixture or using an aqueous 2,4-D and 2,4-
dichlorophenylacetic acid (DPAC) mixture. The largest selectivity coe cient for 2,4-D in the presence of 2,4-DCP was found to be over
18, the largest relative selectivity coe cient between 2,4-D and 2,4-DCP over 9. The static uptake capacity and selectivity coe cient of
the 2,4-D-imprinted functionalized sorbent are higher than those of the non-imprinted sorbent. The imprinted functionalized silica gel
sorbent o ered a fast kinetics for the extraction/stripping of 2,4-D, 73% of binding capacity (200 mg/L 2,4-D onto 20 mg of imprinted
sorbent) was obtained within 5 min and the adsorbed 2,4-D can be easily stripped by the mixture solution of ethanol and 6 mol/L
HCl (V:V =1:1). In a test of five extraction/stripping cycles, the adsorption capacity of the sorbent was all above 93% of that of the
fresh sorbent. Experimental result showed the potential of molecularly-imprinted amino-functionalized sorbent for selective removal of
2,4-D.
