Alkali-resistant polyethyleneimine/triglycidyl isocyanurate nanofiltration membrane for treating lignin lye

Mitigation of Membrane Fouling in Lignin Recovery from Black Liquor via Surface-Patterned Ceramic Membrane

Among the various methods for recovering lignin from black liquor, membrane separation has gained prominence in the paper industry due to its advantages of uniform molecular weight distribution, high recovery rates, and absence of secondary pollution. However, over time, lignin particles tend to deposit and form a cake layer on the membrane surface, leading to membrane fouling and a decline in filtration flux. To address this issue, this study investigates the construction of ceramic membranes with radial rib patterns, and examines the effects of different trans-membrane pressure differences and radial rib patterns on membrane surface shear force and particle deposition. The research findings indicate that at a trans-membrane pressure difference of 0.5 bar and a blade rotation speed of 1000 r/min, the membrane surface experiences the highest shear force. Compared with those without patterns, ceramic membranes with radial rib patterns can more effectively delay the deposition of particles. Furthermore, it was observed that ceramic membranes combining coarse and fine rib patterns exhibit a more pronounced increase in membrane surface shear force.

Rationally Designed Binder with Polysulfide-Affinitive Moieties and Robust Network Structures for Improved Polysulfide Trapping and Structural Stability of Sulfur Cathode

Lithium-sulfur batteries (LSBs) have emerged as a promising next-generation energy storage application owing to their high specific capacity and energy density. However, inherent insulating property of sulfur, along with its significant volume expansion during cycling, and shuttling behavior of lithium-polysulfides (LiPSs), hinder their practical application. To overcome these issues, a crosslinked cationic waterborne polyurethane (CCWPU) is rationally designed as a binder for LSBs. The mechanical robustness of CCWPU enables it to withstand the high stress derived from volume expansion of sulfur, facilitating charge-transferring through conserved charge-transfer pathway and promoting interconversion of LiPSs. Additionally, polar urethane groups offer favorable interaction sites with LiPSs, mitigating shuttling behavior of LiPSs via polar-polar interaction. Density functional theory investigations further elucidate that the incorporation of cationic moieties enhances LiPSs immobilization by confining Sn x- (x = 1 or 2) in LiPSs, thereby improving sulfur utilization. Benefiting from these, the cell with CCWPU demonstrates reduced polarization, superior LiPSs conversion rates, and stable cycling performance. Moreover, water-processable nature of CCWPU aligns with environmental consciousness. These diverse functionalities of CCWPU provide valuable insights for the development of advanced binder for LSBs, ultimately improving the electrochemical performances of LSBs.

Thin-Film Composite Membranes for Hydrogen Evolution with a Saline Catholyte Water Feed

Hydrogen gas evolution using an impure or saline water feed is a promising strategy to reduce overall energy consumption and investment costs for on-site, large-scale production using renewable energy sources. The chlorine evolution reaction is one of the biggest concerns in hydrogen evolution with impure water feeds. The "alkaline design criterion" in impure water electrolysis was examined here because water oxidation catalysts can exhibit a larger kinetic overpotential without interfering chlorine chemistry under alkaline conditions. Here, we demonstrated that relatively inexpensive thin-film composite (TFC) membranes, currently used for high-pressure reverse osmosis (RO) desalination applications, can have much higher rejection of Cl- (total crossover of 2.9 ± 0.9 mmol) than an anion-exchange membrane (AEM) (51.8 ± 2.3 mmol) with electrolytes of 0.5 M KOH for the anolyte and 0.5 M NaCl for the catholyte with a constant current (100 mA/cm2 for 20 h). The membrane resistances, which were similar for the TFC membrane and the AEM based on electrochemical impedance spectroscopy (EIS) and Ohm's law methods, could be further reduced by increasing the electrolyte concentration or removal of the structural polyester supporting layer (TFC-no PET). TFC membranes could enable pressurized gas production, as this membrane was demonstrated to be mechanically stable with no change in permeate flux at 35 bar. These results show that TFC membranes provide a novel pathway for producing green hydrogen with a saline water feed at elevated pressures compared to systems using AEMs or porous diaphragms.

Ratiometric Luminescent Thermometer Based on the Lanthanide Metal-Organic Frameworks by Thermal Curing

The high-performance optical thermometer probes are of great significance in diverse areas; lanthanide metal-organic frameworks (Ln-MOFs) are a promising candidate for luminescence temperature sensing owing to their unique luminescence properties. However, Ln-MOFs have poor maneuverability and stability in complex environments due to the crystallization properties, which then hinder their application scope. In this work, the Tb-MOFs@TGIC composite was successfully prepared using simple covalent crosslinking through uncoordinated -NH₂ or COOH on Tb-MOFs reacting with the epoxy groups on TGIC {Tb-MOFs = [Tb₂(atpt)₃(phen)₂(H₂O)]_n; H₂atpt = 2-aminoterephthalic acid; phen = 1,10-phenanthroline monohydrate}. After curing, the fluorescence properties, quantum yield, lifetime, and thermal stability of Tb-MOFs@TGIC were remarkably enhanced. Meanwhile, the obtained Tb-MOFs@TGIC composites exhibit excellent temperature sensing properties in the low-temperature (S_r = 6.17% K^-1 at 237 K), physiological temperature (S_r = 4.86% K^-1 at 323 K), or high-temperature range (S_r = 3.88% K^-1 at 393 K) with high sensitivity. In the temperature sensing process, the sensing mode of single emission changed into double emission for ratiometric thermometry owing to the back energy transfer (BenT) from Tb-MOFs to TGIC linkers, and the BenT process enhanced with the increase of temperature, which further improved the accuracy and sensitivity of temperature sensing. Most notably, the temperature-sensing Tb-MOFs@TGIC can be easily coated on the surface of polyimide (PI), glass plate, silicon pellet (SI), and poly(tetrafluoroethylene) plate (PTFE) substrates by a simple spraying method, which also exhibited an excellent sensing property, making it applicable for a wider T range measurement. This is the first example of a postsynthetic Ln-MOF hybrid thermometer operative over a wide temperature range including the physiological and high temperature based on back energy transfer.