Interactions between organic flocculant PAN-DCD and dyes.
Organic flocculant polyacrylonitrile-dicyandiamide (PAN-DCD) was characterized by IR, 1H NMR and 13C NMR spectra. Polar groups, such as triazine, carboxyl, amidine, carbonamide and non-polar groups, such as methylene were identified in the macromolecular chain of PAN-DCD. The flocculant effectively decolorized the examined dyes in their aqueous solutions under acid condition. By comparing the IR spectra of dyes with that of PAN-DCD and that of flocs formed, weak chemical interactions between amino in PAN-DCD side chain and sulfonic acid group in the dye molecules were observed through the formation of -NH3+ SO3(-)-, NH2+ SO3(-)- or/and =NH+ SO3(-)-. By using equilibrium dialysis technique, the hydrophobic interactions between PAN-DCD and the dyes in the binding process were also observed from the experimental results. The binding extent of PAN-DCD to dye KN-R was greater than that of MO. The addition of urea into the binding system of KN-R by PAN-DCD reduced the first binding constant K from 12.2 x 10(5) (without urea) to 3.48 x 10(5) (with urea).
Yu
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Y
College of Environmental Science and Engineering, Nankai University, Tianjin, People's Republic of China.
Zhuang
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Zou
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QM
D000180:Acrylic Resins / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D003484:Cyanamide / Q000737:chemistry*; D005427:Flocculation; D009682:Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D014874:Water Pollutants, Chemical / Q000032:analysis
D000180:Acrylic Resins; D004396:Coloring Agents; D014874:Water Pollutants, Chemical; C010504:polyacrylonitrile; D003484:Cyanamide