Comparative Evaluation of Natural Polyelectrolytes Psyllium and Chitosan as Coagulant Aids for Decolourization of Dye Solutions

The aqueous solutions of three different highly coloured anionic dyes (reactive, acidic and direct dyes), commonly used in the dyeing process, were studied for decolourization by coagulation. For optimum results the variables studied with polyaluminium chloride (PAC) were pH, dosage and temperature. Coagulation efficiencies of natural polyelectrolytes such as psyllium and chitosan alone or as coagulant aids in conjunction with PAC were studied and compared. In conjunction with a minimal dose of PAC, chitosan and psyllium were found to be very effective for the decolourization of acidic and direct dyes. Reactive dyes with anthraquinone chromophore were the most difficult to decolourize.

[1]  James K. Edzwald,et al.  Coagulation in Drinking Water Treatment: Particles, Organics and Coagulants , 1993 .

[2]  J. Cyong,et al.  Relationship between chemical structure and anti-complementary activity of plant polysaccharides , 1985 .

[3]  J. Gregory,et al.  Flocculation and sedimentation of high-turbidity waters , 1991 .

[4]  J. V. Benschoten,et al.  Chemical aspects of coagulation using aluminum salts—I. Hydrolytic reactions of alum and polyaluminum chloride , 1990 .

[5]  Samia Al Azharia Jahn,et al.  Using Moringa Seeds as Coagulants in Developing Countries , 1988 .

[6]  Sheng H. Lin,et al.  Continuous treatment of textile wastewater by combined coagulation, electrochemical oxidation and activated sludge , 1996 .

[7]  Ibrahim M. Banat,et al.  Microbial decolorization of textile-dye-containing effluents A review , 1996 .

[8]  R. Srinivasan,et al.  Plantago psyllium-Grafted-Polyacrylonitrile— Synthesis, Characterization and Its Use in Suspended and Dissolved Solid Removal from Textile Effluent , 2002 .

[9]  Grant,et al.  Natural coagulants for appropriate water treatment: a novel approach , 1990 .

[10]  G. Boardman,et al.  Fate of azo dyes in sludges , 1994 .

[11]  J. Kennedy,et al.  The gel nature and structure of the carbohydrate of ispaghula husk ex Plantago ovata Forsk , 1981 .

[12]  Vandana Singh,et al.  Cassia angustifolia seed gum as an effective natural coagulant for decolourisation of dye solutions , 2002 .

[13]  G. C. Tucker.  Plantago major L. , 2004 .