Qiang Gu

Synthesis, characterization and evaluation of dewatering properties of chitosan-grafting DMDAAC flocculants.

Flocculation is one of the most widely applied techniques for water treatment and sludge dewatering. A fresh environmentally friendly and powerful flocculant is highly eager in the sludge dewatering area. In this work, a highly efficient cationic flocculant, chitosan-g-PDMDAAC was synthesized through grafting a monomer, dimethy ldiallyl ammonium chloride(DMDAAC), onto chitosan initiated by ceric sulfate under ultrasonic-assisted and conventional heating condition. The graft copolymer was characterized using FT-IR, XRD and SEM. Further, the dewatering performance of municipal activated sludge was evaluated by the filter cake moisture content and specific resistance in filtration. Its application as a flocculant for wastewater treatment was investigated. The prepared chitosan-g-PDMDAAC showed a highly effective flocculation capability for activated sludge compared with chitosan, polyacrylamide(PAM), cationic polyacrylamide(CPAM).

Ultrasonic-assisted synthesis of 1,4-disubstituted 1,2,3-triazoles via various terminal acetylenes and azide and their quorum sensing inhibition

An efficient synthesis of 1,4-disubstituted 1,2,3-triazole derivatives was studied. 1,4-Disubstituted 1,2,3-triazoles containing isoxazole and thymidine structures were synthesized in 84-96% yields starting from various terminal isoxazole ether alkynes and β-thymidine azide derivatives via a 1,3-dispolar cycloaddition using copper acetate, sodium ascorbate as the catalyst under ultrasonic assisted condition. All the target compounds were characterized by HRMS, FT-IR, 1H NMR and 13C NMR spectroscopy. Furthermore, the quorum sensing inhibitory activities of synthesized compounds were evaluated with Chromobacterium violaceum (C. Violaceum CV026) based on their inhibition of violacein production, with compound C10-HSL as a positive control. The compounds 8a, 8c and 8f exhibited considerable levels of inhibitory activity against violacein production, and IC50 values were 217±19, 223±20 and 42.8±4.5μM, respectively, which highlighted the potential of these compounds as lead structures for further research towards the development of novel QS inhibitors.

2,4,5-Tri-2-furyl-1H-imidazole

In the crystal of the title compound, C15H10N2O3, the molecules are linked together by intermolecular N—H⋯N hydrogen bonds into chains along the c axis. The crystal structure also shows weak intermolecular C—H⋯π hydrogen bonds. The three furanyl rings bonded to the imidazole core are not coplanar with the latter; the dihedral angles between the furanyl and imidazole ring planes are 29.3 (2), 19.4 (2), and 4.8 (2)°.