Reduced membrane rejection performance has been a big challenge for the membrane industry when dealing with concentrated complex feed solution. In this study, a robust mixed matrix membrane (MMM) of polyimide/graphene oxide (PI/GO) was systematically fabricated and modified using highly hydrophilic ethylenediamine (EDA) cross-linker under control conditions and tested for the recovery of succinate from fermentation broth at increasing feed concentration. The effects of membrane evaporation time (30, 45 and 60 s) and cross-linking time (0, 1 and 2 h) were investigated for achieving a membrane with inherent physicochemical properties of high succinate rejection and separation factor. The membrane was also tested for the recovery of succinate from by-products solution containing acetate and formate at increasing succinate concentration from 10 to 50 g/L. The result shows a successful cross-linking of PI/GO membrane using EDA with improved hydrophilicity. This is reflected in the reduced membrane contact angle and the increased membrane pure water flux to an average of 70% increase. At increasing feed solution from 10 to 50 g/L, the results showed that the cross-linking process reduced the dropped-in succinate rejection from 33 % for 1 h cross-linking time to 7% for 2 h cross-linking time compared to the non-cross-linked membrane of 73 % dropped-in succinate rejection. At 2 h cross-linking time, 91 % and 84 % succinate rejections were obtained for 10 and 50 g/L feed solutions, respectively. The improved succinate rejection was also reflected in the enhanced membrane selectivity performance. However, not much effect on succinate recovery was seen for the cross-linked membrane fabricated at a different evaporation time. This study herein introduces an alternative modification of cross-linking process on polymeric membrane in dealing with the enduring problem of reduced membrane performances when elevated succinate concentration was utilised.

当处理浓缩的复杂进料溶液时，降低的膜截留性能一直是膜行业的一大挑战。在这项研究中，在控制条件下使用高亲水性乙二胺（EDA）交联剂系统地制造和改性了一种坚固的聚酰亚胺/氧化石墨烯（PI / GO）混合基质膜（MMM），并测试了其从发酵液中回收琥珀酸酯的能力。在增加饲料浓度时。研究了膜蒸发时间（30、45和60 s）和交联时间（0、1和2 h）对获得具有固有琥珀酸高截留率和分离因子的理化性质的膜的影响。还测试了膜的琥珀酸酯浓度从10到50 g / L的增加，从含有乙酸盐和甲酸的副产物溶液中回收了琥珀酸盐。结果显示使用具有改善的亲水性的EDA成功地使PI / GO膜交联。这反映在减少的膜接触角和增加的膜纯水通量上，平均增加了70％。当进料溶液从10 g / L增加到50 g / L时，结果表明，与之相比，交联过程将琥珀酸的截留率从1小时交联时间的33％降低到2小时交联时间的7％。非交联膜的琥珀酸酯截留率降低了73％。在2 h交联时间，分别对10 g / L和50 g / L的进料溶液获得91％和84％的琥珀酸酯截留率。改进的琥珀酸盐截留率也反映在增强的膜选择性性能上。然而，对于在不同蒸发时间下制备的交联膜，对琥珀酸盐的回收率影响不大。本文中的这项研究引入了在聚合物膜上的交联过程的另一种改进，以解决利用琥珀酸浓度升高时膜性能下降的持久问题。