Flux enhancement in reverse osmosis membranes induced by synergistic effect of incorporated palygorskite/chitin hybrid nanomaterial

The substrate of RO thin film composite membranes offers support for rejection layer formation. It remarkably affects the physicochemical and structural properties of the developed rejection layer. This denotes the relevance of substrates modification in realizing optimized substrate structure in terms of porosity, thickness and tortuosity with the goal of obtaining highly selective and enhanced hydrophilic membrane. Polyamide thin film nanocomposite (TFN) membranes with its polysulfone (PSF) substrate embedded with palygorskite-chitin (PAL-CH) hybrid nanomaterial have been fabricated in this study. The hybridization of palygorskite and chitin nanofibers was performed under the collision as well as the shear force of ball mill. The TFN membranes with different loadings of PAL-CH in the PSF layer were characterized and applied for desalination process. The incorporation of PAL-CH hybrid increased the finger like structure formation and improved the overall hydrophilicity besides highly cross linked and thinner PA layer. The flux of the neat and PAL-CH membranes was 0.82 L m(-2) h(-1) and 2.4 L m(-2) h(-1) respectively. The developed membranes exhibited remarkably improved pure water flux without compromising the salt rejection. Flux enhancement of 192.7% was achieved using 0.01 wt% PAL-CH3 hybrid nanomaterial.

Automated summary

The substrate of RO thin film composite membranes plays a crucial role in supporting rejection layer formation, highlighting the importance of optimizing substrate structure for selective and enhanced hydrophilic membranes. In this study, TFN membranes embedded with PAL-CH hybrid nanomaterial were successfully developed, leading to improved hydrophilicity and pure water flux.