چكيده لاتين :
Anumber of composite membranes have been investigated for the separation of
water from miscible organic-water mixtures. Organic solvents studied were
ethanol, propanol-2 and acetone. Each composite membrane was formed of at
least two fused layers. One layer was prepared from a mixture of natural rubber latex
solution and the other layer, from a solution of hydrophilic colloid between 1.25 to 20 percent
by weight on a dry rubber basis. Four hydrophilic colloids with not more than three
different molecular masses for each type were used in the preparation of membranes.
Each composite membrane was vulcanized before use in an all stainless steel membrane
cell. These perm-selectivities have been compared with those obtained from the use of
vulcanized natural rubber latex membranes only. The special novel design of this cell
along with the entire equipment used, are described and discussed. The method of forming
a thin film as well as the techniques for checking its soundness and finally, the proposed
mechanism and a model that may be responsible for enhancing the permeation of
water through the composite membranes are also discussed. The incorporation of a layer
of alginic acid hydrocolloid in the composite membrane did increase the separation factor
of water from ethanol-water mixtures by a factor of 24 in comparison with that of a natural
rubber membrane alone. Similarly, the separation factors for water with hydrocolloids
hydroxypropyl methyl cellulose and methyl cellulose from the solutions containing
propanol-2 and acetone were 13.50 and 11, respectively.
