Creating smart chlorine-resistant polyamide reverse osmosis membranes via self-healing temperature-responsive nanocontainer functionalization

We present an innovative solution for improving the chlorine resistance of polyamide RO membranes. Our method involves the design of temperature-specific (70 degrees C) responsive nanocontainers (T-RNC) through layer-bylayer self-assembly on a monodisperse SiO2 nanoparticle core. These nanocontainers, measuring 25 nm in size, are embedded within a thin film nanocomposite (TFN) membrane, resulting in a homogeneous surface structure with increased roughness and strong hydrophilicity. The precise temperature-responsive properties of T-RNC enable the dissolution of the encapsulated shell material, releasing SS molecules containing amino and carboxyl groups. These molecules effectively bind to broken amid bonds within the PA layer, repairing structural damage caused by chlorination and significantly enhancing the membrane's chlorine resistance. Extensive testing revealed that the temperature-responsive TFN membrane maintained over 90 % NaCl rejection, even after exposure to 18,000 ppm.h of chlorination. In contrast, the control group lacking temperature-responsive TFN and TFC membranes exhibited reduced rejection rates of 62.15 % and 71.24 %, respectively. Additionally, the TFN membranes exhibited excellent water permeability and resistance to contamination. Our findings offer promising avenues for researchers to explore the development of intelligent and chlorine-resistant polyamide RO membranes, with a particular focus on chlorination-remediation techniques.