MORPHOLOGY AND HYDROPHOBICITY OF AGAR, BEESWAX, AND AGAR-BEESWAX EMULSION COATED ON POROUS ALUMINA SUPPORT

Abstract

Membrane degassing technology is based on the principle of hydrophobicity. Up-to-date, the membrane degasifier is industrially produced by extrusion and then stretched to form a hollow fiber shape with long narrow pores along membrane length. Typical degasifiers are engineered with polypropylene (PP) due to its high toughness and flexibility. However, finding environmentally safe materials at a low cost for replacement for PP would be worth investigating. In this work, agar, beeswax, and their emulsion were coated on a tubular alumina membrane for use as a selective layer of the membrane degasifier. The agar solution with different concentrations between 1 and 4 wt% was coated on the alumina membrane support to create a pore network. Beeswax was coated on agar film to enhance the hydrophobicity. SEM images showed that the increase in the concentrations of agar led to a decreased pore size of the selective layer. Moreover, the contact angle increased up to 100° when the concentration of agar solution increased to 4 wt%. The increase in contact angle to 120° was obtained when the beeswax was coated, appropriate for hydrophobic applications.