Membrane fouling significantly limits the application of membrane separation technology in the treatment of textile dyeing wastewater. In this study, a loose nanofiltration membrane made of polybenzimidazole (PBI) with enhanced antifouling and high-efficiency dye/salt separation capabilities was developed through Ag@UiO-66-NH₂ immobilization and hydrophilic polymer brush grafting. Initially, Ag@UiO-66-NH₂ nanoparticles, possessing antibacterial properties, were incorporated into the PBI base membrane. Subsequently, a brush-like antifouling layer was constructed on the membrane surface by grafting linear polypropylene glycol (PPG) and polyethylene glycol (PEG). Experimental results revealed that the grafting modification substantially improved the membrane's performance: the rejection of the small-molecule dye Methyl Red increased from 16.8 % to 59.6 %, and the membrane surface hydrophilicity was enhanced, leading to a slight improvement in pure water flux. Additionally, the grafted layer effectively suppressed the adsorption of bovine serum albumin, with a flux recovery rate remaining above 90 % after four fouling cycles. Furthermore, the membrane exhibited rejection of <10 % for inorganic salts (Na 2 SO 4 , NaCl, MgSO 4 and MgCl₂), achieving efficient separation of dyes and salts. In tests with simulated textile dyeing wastewater, the membrane's rejection for industrial dyes remained stable at over 90 %, and the addition of surfactants and auxiliaries had no significant impact on its performance. This study shows that the combination of immobilizing MOF nanoparticles with controlled release properties of biocides and grafting hydrophilic polymer brush can effectively improve the separation efficiency and antifouling performance of the membrane, which provides a new method for the treatment of complex textile printing and dyeing wastewater.
Mercury ions (Hg 2+ ) are extremely toxic, posing severe risks to human health and ecosystems even at trace concentrations. Their prevalence necessitates the development of rapid, selective, and portable methods for on-site Hg 2+ detection in environmental monitoring. Here we report a surface-enhanced Raman scattering (SERS) sensor that employs a capillary-immobilized Ag@UiO-66-NH 2 nanocomposite as the substrate for the indirect detection of Hg 2+ . The inner wall of a glass capillary was amino-functionalized and sequentially decorated with silver nanoparticles (AgNPs) and a zirconium-based metal–organic framework (UiO-66-NH 2 ). After that, Dithizone (DTZ) was immobilized onto the resulting Ag@UiO-66-NH 2 composite to form stable Raman-active complexes. In the presence of Hg 2+ , the strong chelation between DTZ and Hg 2+ induces distinct SERS signal changes, enabling highly sensitive and selective detection of Hg 2+ . A key advantage of this sensor is the ability to directly load microliter-scale samples into a pretreated capillary for on-site analysis using a portable Raman spectrometer. The sensor exhibits a linear response between the DTZ signal intensity and Hg 2+ concentration over a broad range (10 −12 –10 −5 mol·L −1 ), with excellent linearity (R 2 = 0.9900), uniformity, reproducibility, and selectivity against common interfering ions. This method was validated in environmental water samples, demonstrating good agreement with ICP-MS while simplifying sample handling and minimizing pretreatment. These findings underscore the sensor's considerable potential for practical, on-site monitoring of Hg 2+ in both environmental and industrial contexts.
危险品化学品经营许可证（带存储）