In-situ growth of layered double hydroxides (LDHs) onto thin-film composite membranes for enhanced reverse osmosis performance

Thin-film nanocomposite (TFN) membranes have been intensively investigated because of their outperformance in desalination. However, in most cases, nanomaterials have to be synthesized in advance before preparing TFN membranes, which is usually both material- and time-consuming. Herein, a new methodology to prepare TFN membranes is illustrated by in-situ growth of layered double hydroxides (LHDs) onto the surfaces of the pristine thin-film composite (TFC) membranes. By fine tuning the concentrations of nanomaterial precursors and optimizing the preparation process, a water permeance of 3.36 L m−2 h−1 bar−1 (LMH bar−1) with a salt rejection of 98.22 % is obtained for the optimal TFN membrane. Compared to the pristine membrane, the water permeance is improved by 84 % without jeopardizing the salt rejection notably. This method offers us a new route to fabricate TFN membranes for practical use.