Coagulation Mechanism of Salt Solution-Extracted Active Component in Moringa oleifera Seeds

This study focuses on the coagulation mechanism by the purified coagulant solution (MOC-SC– ) with the coagulation active component extracted from M. oleifera seeds using salt solution. The addition of MOC-SC- tap water formed insoluble matters. This formation was responsible for kaolin coagulation. On the other hand, insoluble matters were not formed when the MOC-SC- was added into distilled water. The formation was affected by Ca2+ or other bivalent cations which may connect each molecule of the active coagulation component in MOC-SC- and form a net-like structure. The coagulation mechanism of MOC-SC- seemed to be an enmeshment of Kaolin by the insoluble matters with the net-like structure. In case of Ca2+ ion (bivalent cations), at least 0.2 mM was necessary for coagulation at 0.3 mg C l−1 dose of MOC-SC- . Other coagulation mechanisms like compression of double layer, interparticle bridging or charge neutralization were not responsible for the coagulation by MOC-SC- .