Paper title:

Carbon nanotube membranes for desalination and water purification: Challenges and opportunities

 

Journal:

Nano Today (2012) 7, 385?389

 

Author/s:

Soumitra Kar, R.C. Bindal, P.K. Tewari

Desalination Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India

 

Summary:

The paper reviews the application of carbon nanotubes (CNTs) as membranes for desalination and water purification.

The unique properties of CNTs give them the potential to overcome the tradeoff between achieving high water flux and high selectivity at the same time. Moreover, the nanotube ends could be functionalized in order to control the separation properties of a CNT and how it handles both hydrophobic and hydrophilic fouling. CNTs have also shown antimicrobial ability towards gram-positive and gram-negative bacteria, thereby confirming its potential to prevent/reduce biofouling tendencies.

The opportunities offered by CNTs can’t be fully maximized at the moment because of some of the challenges in using them. From the growth of CNTs, to the evaluation of membrane performance, to the scale up for industrial applications, many difficulties are encountered in every step of employing CNT membranes.

It was mentioned that the benefits of CNTs can be exploited by integrating them within a matrix so significant research about how to embed them in a polymer matrix had been done through the years.

The paper also outlined 4 different approaches for fabricating CNT membranes:

1.   Template-synthesized CNT membrane: carbon materials are deposited inside preexisting ordered porous membranes

2.   Dense-array outer-wall CNT membrane: uses the interstices between nanotubes in a vertical array of CNTs

3.   Open-ended CNT membrane: as-grown vertically-aligned CNTs (ex. Through chemical vapor deposition method) are encapsulated using a space-filling inert polymer or ceramic matrix, and are then opened up by plasma chemistry

4.   Mixed-matrix membrane: nanotubes become fillers in a polymer matrix

 

 

 

Contribution and application:

This review paper provides a good, 2-way perspective about the real applications of CNT in desalination. Aside from the opportunities and benefits, the authors of the paper mentioned the challenges met by using CNT membranes.

By: Hannah Ebro

hannah@gist.ac.kr