In-situ crystallization of rigid porous nanoparticles in the GO membrane for stable dye desalination

Graphene oxide (GO) membranes offer substantial promise in the field of dye desalination. However, the low water permeance and structural instability limit their practical application. To address these challenges, a nanoparticle intercalation coupled with in-situ crystallization strategy was developed to tailor the microstructure of GO membranes. This approach enhances the interlayer spacing and strengthens the mechanical properties of the membrane. Rigid, porous MIL-100(Fe) nanoparticles are formed at the defective regions and interlayer spaces of the GO membrane through the in-situ conversion of pre-intercalated iron hydroxide nanoparticles. The MIL-100(Fe)@GO (MGO) membrane features an enlarged interlayer spacing and porous architecture, enabling it to attain a water permeance of 89.4 LMH/bar—a 22-fold improvement compared to the GO membrane. Additionally, the porous structure and negatively charged membrane surface improve dye rejection efficiency (e.g., 98.8 % for Methyl Blue (MB)) while maintaining low rejection of inorganic salts (e.g., <5 % for NaCl). More importantly, the insertion of rigid MIL-100(Fe) nanoparticles imparts exceptional stability to the membrane under cross-flow operation, including no decline in water permeance under high pressure, chemical stability across various pH conditions, and long-term operational stability. These characteristics make the MGO membrane a highly promising option for dye desalination applications.