Development of Nano-Carbon Bucky-Paper Membranes for Membrane Distillation

Membrane distillation (MD) is a special evaporation process to produce fresh water from seawater or contaminated water using membranes. MD has advantages over other evaporation technologies such as multi-stage flash vaporization (MSF) and multi-effect distillation (MED) due to its relatively low energy requirements, allowing the use of solar energy as its heat source. Nevertheless, lack of membrane materials for MD process hinders its practical implementation for desalination and water treatment. In this study, membranes made of carbon nanotube (CNT) are presented for MD. Flat sheet hydrophobic membranes made of polyvinylidene fluoride (PVDF) were selected as supports for bucky-paper membranes, allowing formation of CNT bucky-paper without chemical reactions. Laboratory-scale systems were used to evaluate their potential and performance in direct contact MD. Water permeability and salt rejection were analyzed for each case. D.I water and synthetic feed water were used for the lab-scale tests. It was demonstrated that the physical immobilization of CNT on a hydrophobic membrane changed led to an increase in vapor permeability while improving salt rejection.