Abstract
Flocculation of bentonite suspensions by bioflocculant produced by the cyanobacterium Phormidium species strain J1 was correlated with the adsorption mechanism of the flocculant on the bentonite particles in the presence of various CaCl2 concentrations. The optimal flocculant concentration decreased with an increase in CaCl2 concentration, and the adsorption increased with the increase in CaCl2 concentration. Langmuir-type adsorption isotherms were obtained yielding ΔG°ads of - 12 kcal mol-1, at any CaCl2 concentration, while the maximum adsorption increased with the increase in CaCl2 concentration. From measurements of electrophoretic mobility and Ca2+ uptake by the particles and the flocculant if was concluded that the role of CaCl2 is to increase the amount of adsorbed flocculant at any given flocculant concentration, thus shifting the optimal flocculant concentration toward lower values.
Original language | American English |
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Pages (from-to) | 337-349 |
Number of pages | 13 |
Journal | Colloids and Surfaces |
Volume | 48 |
Issue number | C |
DOIs | |
State | Published - 1990 |