Researchers develop novel antifouling nanofiltration membranes utilizing ionic liquid

A brand new post-modification technique has been proposed by a analysis group led by Prof. Wan Yinhua from Institute of Course of Engineering (IPE) of the Chinese language Academy of Sciences, aiming to attain excessive separation selectivity and powerful fouling resistance of nanofiltration (NF) membranes. The technique includes polyamide swelling rearrangement induced by ionic liquid (IL), which facilitates polyelectrolyte deep grafting. The research was revealed within the AIChE Journal.

NF is a promising low-energy separation course of for water purification and useful resource restoration. Nonetheless, membrane fouling, which refers back to the accumulation of gear on the membrane floor and pores, stays a persistent downside throughout sensible purposes. It could possibly trigger elevated transmembrane resistance, decreased permeate flux, and adjustments in separation selectivity, resulting in a deterioration within the high quality of the produced water.

Publish-grafting has been generally used to switch NF membranes and scale back fouling tendency by adjusting their hydrophilicity and charged properties. Nonetheless, floor grafting usually ends in important pore narrowing or blocking, resulting in a loss in permeability. As well as, monocharged surfaces wrestle to withstand blended foulants with completely different costs.

“In our technique, we used an ionic liquid (IL)-ethanol (EtOH) to induce the deep grafting of polyethyleneimine (PEI) and rearrange the polyamide layer, bettering the floor and aperture properties of the NF membrane,” Prof. Wan defined.

The proposed system utilized the sturdy affinity of the IL to the polyamide layer and the low diffusion steric hindrance of EtOH to induce polyamide swelling and obtain deep grafting of PEI. This additionally allowed for focused filling of bigger pores, leading to a narrower pore measurement distribution. The deep grafting of amino teams made the polyamide layer extremely hydrophilic and practically charge-neutral, thereby sustaining glorious antifouling potential towards hydrophobic macromolecules and blended charged molecules.

Moreover, the NF membrane demonstrated exceptional long-term antifouling and separation selectivity stability when examined with coking wastewater and molasses, respectively. Its efficiency was corresponding to NF270.

“This research highlights the potential of utilizing IL-induced deep grafting of polyelectrolytes to enhance the antifouling efficiency of NF membranes,” mentioned Prof. Luo Jianquan, the corresponding writer of the research. “It underscores the importance of solvent properties in grafting habits, and offers a flexible platform for the fabrication of superior NF membranes for wastewater remedy and useful resource restoration.”