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

Julcelly Dayara De Oliveira Henriques,Patricia Angélica Vieira,Marina Wendt Pedrassani,Rafael Bruno Vieira,Walderson Klitzke,Thamayne Valadares De Oliveira,André Bellin Mariano

doi:10.1590/s1517-707620190004.0826

Julcelly Dayara De Oliveira Henriques, Patricia Angélica Vieira + Show 5 more

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https://doi.org/10.1590/s1517-707620190004.0826

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Abstract

ABSTRACT 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.

Highlights

Membranas de microfiltração em cerâmica tubular foram preparadas por extrusão de misturas de argilas naturais (NC) e argilas tratadas termicamente (TC) em diferentes frações com a adição de amido de mandioca catiônico
Previous studies have verified that membranes containing treated clay (TC) possess higher hydraulic permeability and permeate flow values than those containing only NC for application in crossflow filtration
This study aimed to increase the mechanical strength without adversely affecting their permeate flow and hydraulic permeability

Summary

Introduction

Membranas de microfiltração em cerâmica tubular foram preparadas por extrusão de misturas de argilas naturais (NC) e argilas tratadas termicamente (TC) em diferentes frações com a adição de amido de mandioca catiônico. As membranas foram usadas para microfiltração de microalga Acutodesmus obliquus com pressão aplicada de 1 bar com taxa de fluxo volumétrica de 250 L/h em uma temperatura de 10 ± 5°C. A eficiência de cada membrana cerâmica foi avaliada em termos de fluxo permeado para água e microalga e permeabilidade hidráulica. A mistura de 70% de TC, 15% de fração de amido e sinterizado em 1150oC exibiu ótimo desempenho em resistência mecânica (15.1±0.2 MPa), fluxo permeado de água de 522.4±0.3 Kg·m−2·h−1, fluxo permeado de microalga de 114.8±0.8 Kg·m−2·h−1 e permeabilidade hidráulica de 568.0±0.3 Kg·m−2·h−1·bar. Filtration using low-pressure membranes has been highlighted as an excellent separation process given its facile operation, low energy input, and high filtering efficiency without the need for additional chemical contaminants to the system [4, 5]. The synthesis of porous ceramics frequently includes a substance which disappears during the thermal treatment of sintering generating an additional network of pores that modify the membrane pore size distribution that could be obtained with the ceramic composition by itself [8]

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