Structure Regulation Improves Performance of Polyamide Composite Membranes

Chinese Academy of Sciences

Membrane separation technology has been widely applied in desalination and CO2 capture. Polyamide composite membranes fabricated via interfacial polymerization process have attracted attention owing to its facile scale-up and cost-efficiency.

Control of surface morphology and structure of polyamide membranes is important in dictating the separation performance.

A research team led by Prof. JIANG Heqing from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS) constructed an ultrathin graphene oxide (GO) interlayer on polyethersulfone macroporous substrate to tailor the structure of polyamide composite membrane, and thus improve the desalination performance.

The related findings were published in ACS Applied Materials & Interface on April 12.

Interfacial polymerization is a reaction-diffusion process, which in critically influenced by the diffusion of activator and inhibitor. It is challenging to regulate the selective layer thickness and structure of polyamide membranes due to the difficulty in tailoring the diffusion of monomers.

In this study, the researchers directly introduced Zr-based metal organic framework into aqueous amine phase, taking advantage of the strong interaction between Zr metal centre and amine monomer to lower amine diffusion, thus generating polyamide membranes with a specific nanoscale striped Turing structure and a selective layer thickness of 145 nm.

The resulting membrane exhibited a higher CO2/CH4 selectivity of 58 and a CO2 permeance of 27 GPU, showing a promising application in CO2 capture and biogas upgrading.

This work was supported by the National Natural Science Foundation of China and the QIBEBT and Dalian National Laboratory for Clean Energy (DNL), CAS.

A Scheme for the synthetic reaction for polyamide membrane with a homogeneous nanoscale striped Turing structure. (Image by JIAO Chengli)

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