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

Abstract

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 4.02 μm. Coating formulation has been optimized to obtain stable suspension. Powder loading of 4 wt.% was found as optimum for obtaining a proper microfiltration membrane with 0.2 μm 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 80 l/m² 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/m²) 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.

Keywords:

• Apatite membrane
• Clay–alumina support
• Color removal
• Membrane regeneration
• Adsorption

Acknowledgements

Financial support from DST, New Delhi, Government of India (DST Sanction No. INT/Tun/P-1(9)/2009, dated 26.03.2012) and Government of Tunisia is highly acknowledge through the Indo-Tunisia Programme of Co-operation in Science & Technology.