Fig. 6. (a) Water flux and (b) removal rate of PIP-TMC, NF-SS, and NF-SH active layers for different heavy metal ions solutions of 10 ppm at 25 °C and 6 bar; (c) durability of NF-SS and NF-SH in a long-time NF operation process for the removal of Hg(ii) ion; (d) comparison of Hg(ii) removal performance of recently reported state-of-the-art TFC PA separation membranes and other benchmark thiol/thio-functionalized porous materials (see Table S1† for details).