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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Fractal dimension of large aggregates under different flocculation conditions

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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: 13/25641-9 - Procedure etermination for image acquisition to determine flocculent particles size in static reactors
Grantee:Pedro Augusto Grava da Silva
Support type: Scholarships in Brazil - Scientific Initiation
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 type: Research Grants - Research Partnership for Technological Innovation - PITE
FAPESP's process: 13/01634-3 - Particle distribution size by image analyses
Grantee:Pamela Moreno
Support type: Scholarships in Brazil - Master