Elucidating the structure of poly dopamine
The corresponding approaches to coat or graft these materials on the membranes are reviewed, and the materials with promising performance are highlighted in this short review.
Hydrophilic materials create a hydration layer on the surface, which acts as a physical and energy barrier preventing foulants from attaching to the surface and thus reduces the fouling [1,15,16].
The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted.
Wastewater reuse and seawater desalination are some of the key solutions in meeting the increasing demand for clean water.
Mitigation of fouling is an important step to retain water permeance and lower operating costs for membranes to be competitive with other technologies.
One effective strategy to mitigate membrane fouling is to enhance antifouling properties by surface modification.
For MF and UF membranes, the contaminants may even block the internal pores (i.e., internal fouling, as shown in Figure 1a).As an energy-efficient and low-cost technology, polymeric membranes permeate pure water and reject contaminants ranging from bacteria in microns to ions in angstroms [1,2,3,4,5].For example, microfiltration (MF) membranes with pore sizes of 1–100 μm can remove microbes, cells and bacteria [1,3]; ultrafiltration (UF) membranes with pore sizes of 1–100 nm can remove small contaminants, such as proteins and viruses [3,6]; nanofiltration (NF) membranes having pore sizes of a few angstroms can remove divalent ions (e.g., Ca) and small molecules with a molecular weight of 200–1000 Da ; and reverse osmosis (RO) membranes with a dense selective layer that can desalinate brackish water and seawater [4,5,7].Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs.
This article reviews various materials with antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance.Two general approaches have been widely explored: coating a thin film on the membrane surface (as shown in Figure 2a) and grafting of polymer chains on the surface (as shown in Figure 2b) [1,3,10].