High performance lamellar structured graphene oxide nanocomposite membranes via Fe3O4-coordinated phytic acid control of interlayer spacing for organic solvent nanofiltration (OSN)

Graphene oxide (GO), a 2D nanomaterial known for its precise molecular sieving, holds potential for Organic Solvent Nanofiltration (OSN) and wastewater treatment. However, challenges such as thin interlayer spacing, extended diffusion pathways, and susceptibility to dehydration and negative charge-induced swelling limit its separation performance. To overcome these limitations, Herein, we have fabricated novel Fe3O4 coordinated PhA intercalated GO nanocomposite membranes. Impressively, these nanocomposite membranes exhibited remarkable separation efficiency for dyes, pesticides, and pharmaceutical ingredients, addressing the drawbacks associated with pristine GO membranes and enhancing their overall performance. The optimum G10(1)/P1.5-F100µL nanocomposite membrane displayed impressive solvent permeance of 40.43, 33.45, 20.70, 16.24, and 5.6 L/m2 h bar for acetone, methanol, water, ethanol, and IPA, respectively, while maintaining a rejection rate of ≥98.97 % for the MO dye (MW = 327.33 g/mol). Furthermore, the membrane exhibited outstanding efficiency in separating tetracycline (TC) in ethanol (≥97.97 %) and Pendimethalin (PM) in water (≥99.88 %). Additionally, it demonstrated high rejection capabilities for MB (≥98 %) and CR (≥98.78 %) in harsh DMF solvent. Importantly, the nanocomposite membrane displayed outstanding durability throughout continuous separation of Pendimethalin (PM) in a water solution over a period of 168 h. The PM separation remained nearly unchanged for the entire 168-hour duration, demonstrating high mechanical strength and chemical stability. Additionally, the single nanocomposite membrane showcased high efficiency in feed change separation, successfully separating CR in ethanol and PM in water. These results, compared to the other GO-based nanocomposite membranes, demonstrate the exceptional stability and immense potential for real OSN applications.