Fabrication and characterization of low cost ceramic membranes for microfiltration of Acutodesmus obliquus using modified clays

Resumo

Tubular ceramic microfiltration membranes were prepared by extruding thermally treated clay (TC) and
raw clay (NC) mixtures in different fractions with the addition of cationic manioc starch. Previous studies
have verified that membranes containing TC possess higher hydraulic permeability and permeate flow
values than those containing only NC for application in crossflow filtration. However, TC membranes
had a low mechanical strength. Therefore, this study aimed to increase the mechanical strength without
adversely affecting their permeate flow and hydraulic permeability. The physical, mineralogical, and
morphological characteristics of the membranes were determined. The membranes were used for
microfiltration of Acutodesmus obliquus microalgae with applied pressure of 1 bar with a volumetric flow
rate of 250 L/h at a temperature of 10 ± 5°C. The efficiency of each ceramic membrane was evaluated in
terms of the permeate flow for water and microalgae and hydraulic permeability. The mixture of 70% TC,
15% starch fractions and sintered at 1150°C exhibited optimal performance in mechanical strength
(15.1±0.2 MPa), water permeate flow of 522.4±0.3 Kg·m−2·h−1, microalgae permeate flow of 114.8±0.8
Kg·m−2·h−1 and hydraulic permeability of 568.0±0.3 Kg·m−2·h−1·bar.
Keywords: membranes, kaolinite, mechanical strength.