High-performance and solvent-resistant TFC membranes fabricated solely from sustainable resources such as plant-based monomers, green solvents and recycled polymer waste.

Green thin-film composite (TFC) membranes can offer a sustainable solution for the separation of complex mixtures in aqueous and organic solvent nanofiltration (OSN). However, the fabrication of TFC membranes has relied on toxic petrochemical-based monomers, solvents, and supports. Herein, we developed a green TFC membrane using solely sustainable resources. A fully biodegradable electrospun nanofibrous support comprising polylactic acid (PLA) and gelatin (as the interlayer) was developed for the TFC membranes. Dimethyl carbonate and water, as green solvents, were used for the dissolution of PLA and gelatin, respectively. The incorporation of the gelatin interlayer enhanced the hydrophilicity of the support, leading to the homogeneous adhesion of the TFC membrane. Green polyamide TFC membranes were fabricated on the porous support via the interfacial polymerization of natural monomers, namely the plant-based genipin in the aqueous phase, and priamine in the green organic solvent eucalyptol. The biodegradability of the support was demonstrated using proteinase K within 10 h. The green TFC membrane showed outstanding acetone permeance up to 10 L m⁻² h⁻¹ bar⁻¹ with a molecular weight cut-off in the range of 178–391 g mol⁻¹. The optimized membrane demonstrated an oil removal rate of 99.6% in the produced water treatment at a water permeance of 5.6 L m⁻² h⁻¹ bar⁻¹. The robustness of the TFC membrane was evidenced through continuous crossflow filtration under 30 bar over seven days. The sustainability of the membrane was assessed and compared against green and conventional membranes. Overall, the excellent solvent stability and OSN performance of the ecofriendly TFC membranes can lead to new advances in sustainable membrane manufacturing.

Poly(ether-ether-ketone) has received increased attention due to its high thermal and chemical stability, and high performance in various applications. However, it suffers from a semi-crystalline morphology, low fractional free volume, and poor processability, requiring the use of harsh acidic solvents, which leads to undesired sulfonation. In this work, three intrinsically microporous poly(ether-ether-ketones) (iPEEKs), incorporating spirobisindane, Tröger's base, and triptycene contorted structures, were developed for organic solvent nanofiltration. Molecular dynamics simulations have assisted the molecular engineering of the polymers and the understanding of the improved membrane performance through the binding energies between solvents and polymers. Application of the design principles of polymers of intrinsic microporosity has led to a paradigm shift with a notable enhancement in both the polymer properties and the subsequently fabricated nanofiltration membranes' performance. The iPEEKs showed excellent solution processability, a high surface area of 205–250 m² g⁻¹, and excellent thermal stability. Mechanically flexible nanofiltration membranes were prepared from N-methyl-2-pyrrolidone dope solution at iPEEK concentrations of 19–35 wt%. The molecular weight cutoff of the membranes was fine-tuned in the range of 450–845 g mol⁻¹ displaying 2–6 fold higher permeance (3.57–11.09 L m⁻² h⁻¹ bar⁻¹) than previous reports. The long-term stabilities were demonstrated by a 7 day continuous cross-flow filtration.

Thin film composite (TFC) membranes is the dominant type of desalination in the field of membrane technology. Most of the TFC membranes are fabricated via interfacial polymerization (IP) technique. The ingenious chemistry of reacting acyl chlorides with diamines at the interface between two immiscible phases was first suggested by Cadotte back in the 1980s, and is still the main chemistry employed now. Researchers have made incremental improvements by incorporating various organic and inorganic additives. However, most of the TFC membrane literature are focused on improving the water desalination performance. Recently, the application spectrum of membrane technology has been expanding from the aqueous environment to harsh solvent environments, now commonly known as Organic Solvent Nanofiltration (OSN) technology. In this work, some of the main additives widely used in the desalination TFC membranes were applied to OSN TFC membranes. It was found that tributyl phosphate (TBP) can improve the solubility of diamine monomer in the organic phase, and sodium dodecyl sulfate (SDS) surfactant can effectively stabilize the IP reaction interface. Employing both TBP and SDS exhibited synergistic effect that improved the membrane permeance and rejection in solvent environments.

Organic solvent nanofiltration (OSN) has been recognized as an eco-friendly separation system owing to its excellent cost and energy saving efficiency, easy scale-up in the narrow area and mild operation conditions. Membrane properties are the key part in terms of determining the separation efficiency in the OSN system. In this review paper, the recently reported OSN thin-film composite (TFC) membranes were investigated to understand insight of membrane materials and performance. Especially, we highlighted the representative study concepts and materials of the selective layer of OSN TFC membranes for non-polar solvents. The proper choice of monomers and additives for the selective layer forms much more interconnected voids and the enhanced microporosity, which can improve membrane performance of the OSN TFC membrane with reducing the transport resistance. Therefore, this review paper could be an important bridge to connect with the next-generation OSN TFC membranes for non-polar solvents.

Objectives:The objective of this study is to confirm the possibility of reduction and consequent dissolution of Li, Ni, Co, and Mn from NCM622 cathodes in spent Li-ion batteries through the anaerobic respiration with Na-lactate by Shewanella putrefaciens.Methods:The method involves using anaerobic microbial respiration to mimic dissimilatory metal oxide reduction, allowing metals to be leached from NCM622 cathodes (LiNi0.6Co0.2Mn0.2O2) under near-neutral pH conditions (~7.5).Results and Discussion:The results show that approximately 26 wt% of the total Li, Ni, Co, and Mn were successfully leached into the solution within two weeks. This approach differs significantly from conventional acidic leaching processes, offering a more environmentally friendly and sustainable alternative. In addition, we provide quantitative information regarding the dissolution of NCM622 when it is exposed in environmental systems.Conclusion:In conclusion, microbial-based metal leaching presents a novel, sustainable pathway for recovering metals from spent Li-ion batteries, addressing environmental concerns and reducing dependence on traditional energy-intensive recovery methods.