Fresh water scarcity has emerged as a big challenge of current era. Desalination of seawater has long been utilized to produce fresh water suitable for human consumption and irrigation in areas of water scarcity, and its use is becoming more widespread across the globe. Currently, the major desalination technologies are based on membrane separation via reverse osmosis (RO). High pressure, and thus significant energy, is required to force water through the membranes. The use of semipermeable membranes containing carbon nanotubes (CNTs) that form continuous pores has been suggested as a way to reduce the cost of desalination via reverse osmosis. Example membranes containing aligned CNTs have been fabricated, but obtaining only the very narrow pores that are able to block the passage of ions while allowing a rapid flow of water remains a challenge and previous computational studies have focused on idealized single-walled nanotubes. We use non-equilibrium molecular dynamics (NEMD) simulations of pressure induced flow of water and aqueous salt solutions through multi-walled CNTs (MWCNT) with the aim of investigating the effect of additional walls on the performance of CNT based membranes. For NEMD simulations, we apply a fixed force on a water salt solution having a defined length to obtain a hydrostatic pressure difference. Simulations on CNT with different number of walls incorporated into membranes have been conducted with a hydrostatic pressure difference in order to determine the ion rejection and water flux.
MULTI-WALLED CARBON NANOTUBES (MWCNTs) MEMBRANES FOR REVERSE OSMOSIS APPLICATION: A SIMULATION STUDY
Tocci E;Rizzuto C;Drioli E
2016
Abstract
Fresh water scarcity has emerged as a big challenge of current era. Desalination of seawater has long been utilized to produce fresh water suitable for human consumption and irrigation in areas of water scarcity, and its use is becoming more widespread across the globe. Currently, the major desalination technologies are based on membrane separation via reverse osmosis (RO). High pressure, and thus significant energy, is required to force water through the membranes. The use of semipermeable membranes containing carbon nanotubes (CNTs) that form continuous pores has been suggested as a way to reduce the cost of desalination via reverse osmosis. Example membranes containing aligned CNTs have been fabricated, but obtaining only the very narrow pores that are able to block the passage of ions while allowing a rapid flow of water remains a challenge and previous computational studies have focused on idealized single-walled nanotubes. We use non-equilibrium molecular dynamics (NEMD) simulations of pressure induced flow of water and aqueous salt solutions through multi-walled CNTs (MWCNT) with the aim of investigating the effect of additional walls on the performance of CNT based membranes. For NEMD simulations, we apply a fixed force on a water salt solution having a defined length to obtain a hydrostatic pressure difference. Simulations on CNT with different number of walls incorporated into membranes have been conducted with a hydrostatic pressure difference in order to determine the ion rejection and water flux.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
