| Full text | |
| Author(s): |
Moruzzi, Rodrigo B.
;
de Oliveira, Andre L.
;
da Conceicao, Fabiano T.
;
Gregory, John
;
Campos, Luiza C.
Total Authors: 5
|
| Document type: | Journal article |
| Source: | Science of The Total Environment; v. 609, p. 807-814, DEC 31 2017. |
| Web of Science Citations: | 13 |
| Abstract | |
The two-dimensional fractal dimension (D-f) of large aggregates of kaolin (>540 mu m) during the shear flocculation process for kaolin solution was investigated using non-intrusive in situ image-based acquisition system. Separate experiments were also carried out for three different sized sub-ranges of large aggregates (0.540-1.125 mm; 1.125-1.750 mm; 1.750-2.375 mm). Digital images were taken at a frequency of 10 Hz for 10 s for each different pairs of gradients of velocity (G(f)) of 20 and 60 s(-1) and flocculation times of 2; 3; 4; 5; 10; 20; 30; 60; 120 and 180 min. For the same conditions, particle size distribution (PSD) was also determined. Under the investigated conditions, the lowest G(f) produced the greatest D-f (1.69) at a flocculation time of 30 min for the whole range of aggregates. Also, the evolution of the longest length of aggregate (l) and D-f with time, showed that the dynamic steady-state was reached at different times for each shear rate and l ranges. However, D-f varied for each size sub-range (ca. 1.1 to 1.8). Finally, the behavior of the aggregate structure may be understood by the predominance of different aggregation mechanisms such as cluster-cluster for G(f) of 60 s(-1) and particle-cluster for G(f) of 20 s(-1). (C) 2017 Elsevier B.V. All rights reserved. (AU) | |
| FAPESP's process: | 10/50694-0 - Development and application of an on-line floc sizer device aiming at the optimization of coagulation/flocculation and filtration |
| Grantee: | Marcelo de Julio |
| Support Opportunities: | Research Grants - Research Partnership for Technological Innovation - PITE |
| FAPESP's process: | 13/25641-9 - Procedure etermination for image acquisition to determine flocculent particles size in static reactors |
| Grantee: | Pedro Augusto Grava da Silva |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |
| FAPESP's process: | 13/01634-3 - Particle distribution size by image analyses |
| Grantee: | Pamela Moreno |
| Support Opportunities: | Scholarships in Brazil - Master |