Selection of substrate manufacturing techniques of polyamine‐based thin‐film composite membranes for forward osmosis process

Abstract

This paper is a comparative study on the preparation techniques used to make the support layer of polyamide‐thin‐film composite forward osmosis (TFC‐FO) membranes. The role played by the support layer preparation technique in membrane performance is thoroughly investigated in this study. Electrospinning is shown to produce membranes of lower structural parameter compared to those obtained by conventional phase inversion techniques. The electrospun polyamide selective layer can also be tailored with the required properties. This makes electrospinning a promising process to design efficient FO membrane substrates. It is shown in this work that the FO water flux is more dependent on the internal structure of the support layer than the preparation materials. The main challenge remaining for substrates to operate in FO is to achieve simultaneously a low structural parameter, a high surface porosity, and the required mechanical properties. As most of today's approaches are not suitable, further materials development is essential in future investigations on TFC‐FO membranes.

Synthesis and characterization ofPES/PSF/PEGby immersion precipitation for Mediterranean seawater desalination byFOmembrane

“…A low S value means that the membrane has the best substrate morphology, which contributed to reducing the dilutive ICP effects for the FO process. [ 75,76 ] The porosity, thickness, and tortuosity are the three micro‐structural parameters of the FO membrane that determine the S value of the FO membrane. [ 77 ] The decreased tortuosity and enhanced porosity were responsible for a significant drop in the S value of the PEG membrane.…”

Development of Support Layers and Their Impact on the Performance of Thin Film Composite Membranes (TFC) for Water Treatment

“…The stable properties of substrate membranes are important for TFC membranes to function in real-life applications [ 18 , 122 , 123 ]. In the ideal state, the functions of the membrane are unaffected by the performance of the substrate membrane, and the mechanical effect of the substrate merely serves as a platform for the formation of the selective layer.…”

“…An essential metric, J s / J w is utilized to evaluate membrane separation selectivity, reflecting the balance between permeability and selectivity [ 174 ]. The surface properties and volume characteristics of the substrate membrane significantly impact membrane separation performance [ 122 ]. Compared to substrates with larger pores, substrates with a higher surface pore rate or pore density favor the formation of more permeable TFC membranes.…”

“…The stable properties of substrate membranes are important for TFC membranes t function in real-life applications [18,122,123]. In the ideal state, the functions of the mem brane are unaffected by the performance of the substrate membrane, and the mechanica effect of the substrate merely serves as a platform for the formation of the selective laye However, in actual situations, the performance of the membrane is influenced by factor such as the hydrophilicity of the substrate membrane [124], the aperture parameter [32,33], and other factors [76,83,98] such as methods used for immersion in water bath [125].…”

Beyond Symmetry: Exploring Asymmetric Electrospun Nanofiber Membranes for Liquid Separation

“…The structural parameter S of the FO membrane defines the average length of water molecules transported across the membrane, which can intuitively measure the severity of the ICP phenomenon in the FO membrane. [ 88 ] The S parameter is proportional to the membrane bulk tortuosity τ (positively), thickness L (positively), and bulk porosity ε (negatively) as in Equation 2). $$$$\begin{equation}S = \frac{{\tau \times L}}{\varepsilon }\end{equation}$$$$…”