Tubular ultrafiltration ceramic membrane based on titania nanoparticles immobilized on macroporous clay-alumina support: Elaboration, characterization and application to dye removal

The development of new membranes with improved separation properties, high mechanical and thermal stability using inexpensive and naturally abundant materials is of utmost importance for sustainable development and environmental applications. Ceramic materials due to their high chemical, mechanical and thermal stability in combination to their facile surface functionalization have inspired material scientists to design innovative low-cost ceramic-based membrane supports. This study focuses on the preparation and characterization of novel asymmetric ultrafiltration ceramic membrane coated with single separation layer made of TiO2 nanoparticles, and its application to removal of alizarin dye from aqueous solutions. The membrane was prepared by a simple and one-step deposition of micrometer-thick titania layer on the internal surface of the tubular-shape porous clay-alumina membrane support from an aqueous colloidal suspension of titanium oxide (TiO2) nanoparticles with size of 10 nm. The colloidal suspension was prepared in the presence of 0.2 wt.% of Dolapix, and 30 g of an aqueous solution of polyvinyl alcohol at 12 wt.% and 66 mL of H2O. Microfiltration tubular supports of 10 mm/7 mm (outer/inner diameter) were prepared through an extrusion method followed by a sintering process using China Clay Rajmahal grade and alumina, as mineral precursors. The composition of 25% of clay and 75% of alumina was selected in this work as it showed a lower sintering temperature (T-f = 1350 degrees C) which could ensure low cost elaboration process, an average water flux of 850 L h(-1) m(-2) bar(-1) as well as enhanced mechanical performance (approximate to 37 MPa) and large porosity (48%) with an average pore diameter of 0.75 mu m. SEM characterization showed that at the sintering temperature of 800 degrees C, the TiO2 nanoparticles coated densely and homogeneously the ceramic support forming a thin layer of about 4.2 mu m in thickness and leading to a clear reduction of the mean pore size (50 nm approximatively) while providing a water permeability of 117 L h(-1) m(-2) bar(-1). The so-designed ultrafiltration (UF) tubular ceramic membrane has proved efficient for alizarin red dye removal with a retention rate of 99% and a permeate flux of 70 L h(-1) m(-2) at pH 9 and a transmembrane pressure of 5 bar. (C) 2017 Elsevier B.V. All rights reserved

Synthesis and characterization of alpha alumina-natural apatite based porous ceramic support for filtration application

The present study reported the synthesis of low-cost ceramic membrane supports. They were prepared by an extrusion method using alumina/natural apatite blends and further consolidated by heat treatment. The chemical composition, structure and particle size of the starting materials were analyzed. The effect of the natural apatite content, as sintering agent, on the microstructure, porosity, flexural strength and linear shrinkage of the prepared supports were studied as a function of sintering temperature. The microstructure exhibited that the sintering temperature decreased with the increment of the apatite content. The porosity and the pore size were controlled by the sintering temperature and the apatite amount added to the starting mixture. The mechanical strength and the linear shrinkage increased with increasing the apatite and the firing temperature. The sample selected for filtration displayed good porosity (45.38%) and pore size of 1.35 mu m giving a high perme-ability 959.64 h(-1) m(-2) bar(-1)

Efficient and Recyclable Heterogeneous Catalyst Based on PdNPs Stabilized on a Green-Synthesized Graphene-like Nanomaterial: Effect of Surface Functionalization

International audienc

Developing of titania-smectite nanocomposites UF membrane over zeolite based ceramic support

International audienc

Preparation and characterization of microfiltration apatite membrane over low cost clay-alumina support for decolorization of dye solution

Apatite material obtained from natural sources of Tunisian mineral has been used for the development of membrane over clay-alumina-based microporous supports. For this purpose, supports of single-channel and 19-channel circular configurations were used. The apatite powder used for membrane preparation had average pore diameter of 4.02m. Coating formulation has been optimized to obtain stable suspension. Powder loading of 4wt.% was found as optimum for obtaining a proper microfiltration membrane with 0.2m pore diameter. Single-channel membrane was used for characterization. The application to color removal from synthetic reactive dye solution was performed using membrane with 19-channel configuration. An average water flux of 200 and 80l/m(2)h was obtained for 19-channel support and membrane, respectively, in laboratory scale setup. Reactive red dye removal from synthetic dyeing solution was achieved up to 99%. Resulting saturated membrane was successfully regenerated using H2O2 at various concentrations and contact time. Color separation efficiency of the membrane (g/m(2)) has been evaluated as an indicator of membrane regeneration. Moreover, apatite membrane-based separation of reactive red dye has been compared with adsorption using the apatite powder followed by membrane separation. Apatite membrane-based separation was found to be more efficient compared to adsorptive separation using apatite powder