Concentration of carboxylic acids by forward osmosis process

Abstract

To profoundly comprehend the forward osmosis performance, related to the process operation parameters during concentrating carboxylic acid, the mathematical model was developed by thoroughly enumerating and integrating each single logical phenomena equation with pertinent variables during the operation of FO process. By means of Levenberg-Marquardt algorithm, the precise dependent process variables as a function of time were simultaneously determined at each point in simulating time (Dynamic Simulation Model). In this research, the two selected draw solution, NH4Cl and NaCl, were also used to investigate the filtration mechanisms of carboxylic acid in forward osmosis so as to develop consistent mathematical process models. Forward osmosis experimental process was carried out to verify the developed model by using Thin-Film Composite (TFC) FO membrane whereas feed solution was varied types of carboxylic acids and a mixture of them. In case of NH4Cl draw solution, the standard error of prediction (SEP) for weight change of draw solution and pH of feed solution were in the range from 4.20% to 6.99% and 0.52% to 1.13% of single carboxylic acid feed solution and in the range from 5.88% to 9.34% and 0.68% to 0.88% of a mixture of two carboxylic acids, respectively. In case of NaCl draw solution, the standard error of prediction (SEP) for weight change of draw solution and pH of feed solution were in the range from 4.76% to 6.36% and 0.48% to 0.68% of single carboxylic acid feed solution and in the range from 5.31% to 5.90% and 0.66% to 1.15% of a mixture of two carboxylic acids, respectively.