In this study, we investigated the essential role of feed solution pH so as to gain insights into the transport mechanisms of succinic acid concentration by osmotically-driven forward osmosis(FO) process. FO performan...In this study, we investigated the essential role of feed solution pH so as to gain insights into the transport mechanisms of succinic acid concentration by osmotically-driven forward osmosis(FO) process. FO performances including water flux and bidirectional transport of succinate and chloride anions were systematically examined using cellulose triacetate-based FO membrane. Additionally, real seawater was explored as draw solution. Experimental results revealed that the p H-dependent speciation of succinic acid can affect the FO performances. Ionization of succinic acid at higher solution p H enhanced the osmotic pressure of feed solution, thus leading to lower water flux performance. A strong effect was pointed out on the succinate rejection for which nearly 100% rejections were achieved at p H above its pK_(a2) value. The rejection of succinate increased in the following order of chemical form: C_2H_4 C_2O_4H_2 < C_2H_4C_2O_4H~ˉ < C_2H_4C_2O_4^(2-).With real seawater as the draw solution, low to moderate water fluxes(<4 L·m^(-2)·h^(-1)) were observed.The divalent succinate anion was highly retained in the feed side despite differences in the succinic acid feed concentration at p H of approximately 6.90.展开更多
基金the financial support for this work provided by the LRGS/2013/UKM-UKM/PT/03 grant from the Ministry of Education Malaysia
文摘In this study, we investigated the essential role of feed solution pH so as to gain insights into the transport mechanisms of succinic acid concentration by osmotically-driven forward osmosis(FO) process. FO performances including water flux and bidirectional transport of succinate and chloride anions were systematically examined using cellulose triacetate-based FO membrane. Additionally, real seawater was explored as draw solution. Experimental results revealed that the p H-dependent speciation of succinic acid can affect the FO performances. Ionization of succinic acid at higher solution p H enhanced the osmotic pressure of feed solution, thus leading to lower water flux performance. A strong effect was pointed out on the succinate rejection for which nearly 100% rejections were achieved at p H above its pK_(a2) value. The rejection of succinate increased in the following order of chemical form: C_2H_4 C_2O_4H_2 < C_2H_4C_2O_4H~ˉ < C_2H_4C_2O_4^(2-).With real seawater as the draw solution, low to moderate water fluxes(<4 L·m^(-2)·h^(-1)) were observed.The divalent succinate anion was highly retained in the feed side despite differences in the succinic acid feed concentration at p H of approximately 6.90.
