High performance and antifouling vertically aligned carbon nanotube membrane for water purification

• A vertically aligned (VA) carbon nanotube (CNT) membrane was fabricated.
• The VA CNT membrane shows about three times higher water flux than the UF membrane.
• The flux on the VA CNT membrane increases with increasing solvent hydrophilicity.
• The rejection property of the VA CNT membrane was similar to the UF membrane.
• The VA CNT membrane has better biofouling resistance than the UF membrane.

A vertically aligned carbon nanotube (VA CNT) membrane created from the successful fusion of nanotechnology and membrane technology has been stated to be a next generation membrane due to its fast water transport and antimicrobial properties. Although previous studies of the VA CNT membrane reported the potential for fast water transport or desalination by molecular dynamics simulation, this study is the first to report on the feasibility of using the VA CNT membrane for water purification. The VA CNT membrane (4.8 nm of pore diameter and 6.8×1010 #/cm2 of pore density) was fabricated and its flux, rejection performance, and membrane biofouling tendency were evaluated in comparison to the commercial ultrafiltration (UF) membrane. The VA CNT membrane appeared to have a water flux approximately three times higher than the UF membrane and water transport approximately 70,000 times faster than conventional no-slip flow. This higher flux was peculiarly observed in water, the most hydrophilic solvent, while other solvents showed that permeate flux decreased with higher viscosity. The rejection property of the VA CNT membrane as examined by the MWCO measurement was similar to the commercial UF membrane. Additionally, the VA CNT membrane showed better biofouling resistance with approximately 15% less permeate flux reduction and 2 log less bacterial attachment than the UF membrane. This study reports the high potential of the VA CNT membrane with antifouling property in the water purification process.