Abstract
The performance of some complex coagulants derived from weak and medium anionic polymers and medium cationic surfactant
in coagulation-flocculation process for water treatment was experimentally investigated by carrying out kinetic studies and by
determining the optimum coagulant dose. The complex coagulants were prepared from weak anionic and medium anionic
copolymers of acrylamide and sodium acrylate with the commercial names Praestol 2515 and Praestol 2540, and medium
cationic surfactant derived from triethanolamine with the commercial name Tetranyl AT-7590. The coagulation-flocculation
process was studied for suspensions of kaolin particles in tap water. The electro-kinetic studies revealed that the addition of
surfactant leads to a significant decrease of coagulant concentration for which the electro-kinetic potential of the dispersion
medium becomes zero. The favorable influence of the addition of surfactant also resulted from the kinetic studies. Thus, the
formation of some large flocks leads to shortening the flocculation period. These results are consistent with those obtained for
sedimentation velocity, sludge volume and separation efficiency.