Patents
The present invention relates to the use of abundant and generally wasted salt bitterns I with high .osmotic coefficient as draw solution in forward osmosis (FO). A I . > conventional high flux thin film composite polyamide membrane was utilized for this purpose. With sugarcane juice as feed, its fourfold concentration was demonstrated with an energy saving of 97% compared to the energy requirement for conventional multiple effect evaporation. Sucrose loss from feed to draw was <3% and back diffusion of mineral constitu~nts from bittern to feed was-insignificant. using33.5 "Be sea bittern as draw solution and an appropriate ratio of draw solution to feed solution, it was possible to value added the bittern" in as much as the Epsom salt recovered from it after the FO process had a significantly higher purity than the oiiginal bittern. The invention can be applied to dewatering of other,feeds using bittern "as draw solution.