The study of ethanol and water vapour permeation process through alginate membranes modified by magnetic powders

This paper presents a study of novel hybrid membranes consisting of sodium alginate as a polymer matrix and magnetite and two cross-linking agents, that is, orthophosphoric acid and Ca⁺² ions. Ethanol/water separation parameters were determined using the vapour permeation process. The permeate parameters were estimated on the basis of weight loss of the measuring cell over time using an analytical balance. The results have shown the influence of magnetite particles content in the alginate matrix and the effect of cross-linking agents on ethanol/water separation properties. Comparing permeation coefficients of both types of discussed membranes more advantageous separation properties for the membranes cross-linked with orthophosphoric acid were observed. The best ideal selectivity (55.54) was recorded for membranes with iron oxide content between 5 and 10 w/w%. For Ca⁺² ions cross-linked membranes, the highest ideal selectivity coefficient can be obtained at 15–20 w/w% magnetite content (32.18).