![](https://static.wixstatic.com/media/b0cedb_8157bfaa1ad74985b55ce2f98931f2f0~mv2.png/v1/crop/x_8,y_28,w_286,h_311/fill/w_121,h_132,al_c,q_85,usm_0.66_1.00_0.01,enc_auto/b0cedb_8157bfaa1ad74985b55ce2f98931f2f0~mv2.png)
Membrane-based Environmental & Sustainable Technology (MembEST) Group
Department of Civil Engineering, The University of Hong Kong
Rapid and effective
water purification
![](https://static.wixstatic.com/media/b0cedb_ae8c02006d2e4da5995db74b0d0d755df000.jpg/v1/fill/w_388,h_612,al_c,q_80,usm_0.66_1.00_0.01,enc_auto/b0cedb_ae8c02006d2e4da5995db74b0d0d755df000.jpg)
![](https://static.wixstatic.com/media/b0cedb_65f8c9f23b3a4d22bc84f52e83fe9516~mv2.png/v1/crop/x_31,y_31,w_403,h_393/fill/w_518,h_480,al_c,lg_1,q_85,enc_auto/b0cedb_65f8c9f23b3a4d22bc84f52e83fe9516~mv2.png)
Electro-spinning Technique
The nanofibrous membrane is fabricated via an electro-spinning technique which utilizes electric force to spray polymer solution onto nanofibers to stretch their diameter into 10s to 100s nanometer. The nanofibers are then weaved into a nanofibrous membrane which can filter tiny substance. Based on different properties of target contaminants, the team fabricate nanofibers with different dimensions.
![](https://static.wixstatic.com/media/b0cedb_21fdd66fc1d84b44a3a998bc649f09fe~mv2.jpg/v1/crop/x_0,y_0,w_7678,h_3056/fill/w_1040,h_414,al_c,q_85,usm_0.66_1.00_0.01,enc_auto/b0cedb_21fdd66fc1d84b44a3a998bc649f09fe~mv2.jpg)
High Water Permeability
The membrane filter is easily operated via a gravity-driven filtration process.
![](https://static.wixstatic.com/media/b0cedb_9fb04a7c9115441d9a1480f80e777971~mv2.png/v1/fill/w_682,h_240,al_c,lg_1,q_85,enc_auto/b0cedb_9fb04a7c9115441d9a1480f80e777971~mv2.png)
Heavy Metals Removal
> 99%
![](https://static.wixstatic.com/media/b0cedb_2959790568cd49fcb3c568a1317b510d~mv2.png/v1/fill/w_784,h_251,al_c,q_85,usm_0.66_1.00_0.01,enc_auto/b0cedb_2959790568cd49fcb3c568a1317b510d~mv2.png)
The membrane can remove > 99% for lead (Pb), nickel (Ni), cadmium (Cd), and chromium (Cr).
Bacterial Removal
> 99.9999%
Bacteria such as E. coli and B. subtilis are almost totally removed in the process.
![](https://static.wixstatic.com/media/b0cedb_f7ffcecb8bcb46bf9dd4c711136f8ccc~mv2.png/v1/fill/w_725,h_355,al_c,q_85,usm_0.66_1.00_0.01,enc_auto/b0cedb_f7ffcecb8bcb46bf9dd4c711136f8ccc~mv2.png)
![](https://static.wixstatic.com/media/b0cedb_b9f9d55e1a434c53a24f06262288854bf000.jpg/v1/fill/w_627,h_462,al_c,q_80,usm_0.66_1.00_0.01,enc_auto/b0cedb_b9f9d55e1a434c53a24f06262288854bf000.jpg)
Reusability
The membrane can be reused after being rinsed in vinegar.
Regenerated water filter was tested by Pb for over 5-round reuse. The removal efficiency removal kept stable.
![](https://static.wixstatic.com/media/b0cedb_0892d4f871b74d6c8f3b1627515843e4~mv2.jpg/v1/fill/w_649,h_400,al_c,q_80,usm_0.66_1.00_0.01,enc_auto/b0cedb_0892d4f871b74d6c8f3b1627515843e4~mv2.jpg)
Filter Prototypes
![](https://static.wixstatic.com/media/b0cedb_92dc967eba314f61a81f77c699aefbaa~mv2.jpg/v1/fill/w_1085,h_432,al_c,q_85,usm_0.66_1.00_0.01,enc_auto/b0cedb_92dc967eba314f61a81f77c699aefbaa~mv2.jpg)