Protein Based Bioflocculants, Tizazu Mekonnen

1150 WordsSep 2, 20145 Pages
Protein based bioflocculants, Tizazu Mekonnen 1. Mechanismof flocculation Colloidal particles in wastewater suspension normally carry an overall negative charge on their surface that led to electrostatic repulsion. This electrostatic repulsionresult is the stabilization of the suspension as it prohibits the particles to come together and form agglomerate. Flocculants are thus added to change the surface property of such particles and destabilize the suspension so as to facilitate the separation of the solids (Tripathy and Ranjan De 2006). Protein based flocculantsdevelopment for wastewater treatment is mainly built on theirpolyampholite nature associated with the functional groups of the composing amino acids. Most studies in the literature base their protein flocculation mechanisms(Seki et al. 2010, Piazza and Garcia 2013) on theories developed for synthetic polymeric flocculants, such as polyacrylamide. Flocculation mechanisms that could be relevant for protein based flocculants include: (1) Coagulation, (2) Electrostatic patch flocculation and (3) Polymer bridging(Gregory 1973, Sharma et al. 2006, Hjorth and Jorgensen 2012). Coagulation is the process in which colloidal particles and other fine suspensions are destabilized or neutralized to agglomerate induced by addition of inorganic chemicals(Tripathy and Ranjan De 2006). Electrostatic patch mechanism is adsorption of polymers onto local sites of a particle, causing patches of local charge reversal resulting in
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