Inclusion as an efficient purification method for specific removal of tricyclic organic sulfur/nitrogen pollutants in fuel and effluent with cyclodextrin polymers

For specific removal of tricyclic organic sulfur/nitrogen pollutants in fuel and effluent, inclusion not adsorption as an efficient purification method was studied with cyclodextrin polymers. Herein, a novel 2-hydroxypropyl-gamma-cyclodextrin polymer (2-HP-gamma-CDP) was synthesized using tetrafluoroterephthalonitrile (TFTPN) as cross-linker for specific removal of tricyclic organic sulfur/nitrogen pollutants, including 4,6-dimethyldibenzothiophene (4,6-DMDBT) in fuel and methylene blue (MB) in effluent. When the molar ratio of 2-HP-gamma-CD and TFTPN was (1:5) in the synthesis process, the prepared micro-mesoporous 2-HP-gamma-CDP1:5 with a surface area of 365.4m(2).g(-1) has the best removal performance. 2-HP-gamma-CDP1:5 was almost 15 times the commercial activated carbon in removal rate. Meanwhile, the maximum removal capacity of 2-HP-gamma-CDP1:5 was higher than that of most reported traditional adsorbents. Furthermore, 2-HP-gamma-CDP1:5 was easily regenerated with ethanol and almost unchanged in capacity over 5 cycles. It was demonstrated that most of size-matched 4,6-DMDBT and MB removed by 2-HP-gamma-CDP1:5 enter the hydrophobic inner cavity of 2-HP-gamma-CD units. The pleasant inclusion removal method offers the potential applications of 2-HP-gamma-CDPs in fuel desulfurization and effluent purification.