New polymeric membrane nanofiltration for succinate recovery: a comparative study

A Facile Way to Fabricate GO-EDA/Al2O3 Tubular Nanofiltration Membranes with Enhanced Desalination Stability via Fine-Tuning the pH of the Membrane-Forming Suspensions

Pristine graphene oxide (GO)-based membranes have proven promising for molecular and ion separation owing to efficient molecular transport nanochannels, but their separation ability in an aqueous environment is limited by the natural swelling tendency of GO. To obtain a novel membrane with anti-swelling behavior and remarkable desalination capability, we used the Al₂O₃ tubular membrane with an average pore size of 20 nm as the substrate and fabricated several GO nanofiltration ceramic membranes with different interlayer structures and surface charges by fine-tuning the pH of the GO-EDA membrane-forming suspension (pH = 7, 9, 11). The resultant membranes could maintain desalination stability, whether immersed in water for 680 h or operated under a high-pressure environment. When the pH of the membrane-forming suspension was 11, the prepared GE-11 membrane showed a rejection of 91.5% (measured at 5 bar) towards 1 mM Na₂SO₄ after soaking in water for 680 h. An increase in the transmembrane pressure to 20 bar resulted in an increase in the rejection towards the 1 mM Na₂SO₄ solution to 96.3%, and an increase in the permeance to 3.7 L·m^-2·h^-1·bar^-1. The proposed strategy in varying charge repulsion is beneficial to the future development of GO-derived nanofiltration ceramic membranes.

Membrane Purification Techniques for Recovery of Succinic Acid Obtained from Fermentation Broth during Bioconversion of Lignocellulosic Biomass: Current Advances and Future Perspectives

Recently, the bioconversion of biomass into biofuels and biocommodities has received significant attention. Although green technologies for biofuel and biocommodity production are advancing, the productivity and yield from these techniques are low. Over the past years, various recovery and purification techniques have been developed and successfully employed to improve these technologies. However, these technologies still require improvement regarding the energy-consumption-related costs, low yield and product purity. In the context of sustainable green production, this review presents a broad review of membrane purification technologies/methods for succinic acid, a biocommodity obtained from lignocellulosic biomass. In addition, a short overview of the global market for sustainable green chemistry and circular economy systems or zero waste approach towards a sustainable waste management is presented. Succinic acid, the available feedstocks for its production and its industrial applications are also highlighted. Downstream separation processes of succinic acid and the current studies on different downstream processing techniques are critically reviewed. Furthermore, critical analysis of membrane-based downstream processes of succinic acid production from fermentation broth is highlighted. A short review of the integrated-membrane-based process is discussed, as well, because integrating “one-pot” lignocellulosic bioconversion to succinic acid with downstream separation processing is considered a critical issue to address. In conclusion, speculations on outlook are suggested.