Featured Research

from universities, journals, and other organizations

Nano-infused filters prove effective

Date:
April 29, 2010
Source:
Rice University
Summary:
Researchers have found a way to make carbon nanotube membranes that could find wide application as extra-fine air filters and as scaffolds for catalysts that speed chemical reactions.

Nanotubes grown in holes in silicon dioxide wafers have the potential to outperform currently available filters for many uses, Rice researchers found.
Credit: Rice University

Rice University researchers and their colleagues in Finland and Hungary have found a way to make carbon nanotube membranes that could find wide application as extra-fine air filters and as scaffolds for catalysts that speed chemical reactions.

The results reported in the journal ACS Nano show how such filters can remove up to 99 percent of particulates with diameters of less than a micrometer -- or a millionth of a meter. (A human hair is about 100 micrometers wide.)

Using chemical vapor deposition (CVD), a team led by Rice's Robert Vajtai, a faculty fellow in mechanical engineering and materials science, created devices that, at the start of the process, look like tiny showerheads. After 30 minutes in the CVD furnace, the laser-created holes in these silicon dioxide templates fill up with a forest of carbon nanotubes through which only particles on the nanometer scale can pass.

When the tubes are functionalized with catalytic chemicals, particles enter one side of the filter in one form and come out as another. The process is similar to that used by catalytic converters in cars, which convert carbon monoxide into a less-toxic mix of carbon dioxide, nitrogen and water.

"Even when the holes are larger than the particle itself, it can be a very effective filter," Vajtai said. "The basic idea is you have this carbon nanotube forest. The gas flows through, and because of the very small distance between the tubes, gas atoms have to hit many of them before they get out the other side.

"This very strong interaction, compared to macroscopic materials and even some microscopic materials, provides a very good way to make a catalyst template or a filter that is much more effective than a HEPA (high-efficiency particulate-absorbing) filter you can buy at the store," he said.

The filters' permeability depends strongly on how long the nanotubes are allowed to grow, which determines their length and density. The team tested the filters' ability to act as catalysts by depositing palladium onto the nanotubes and using them to turn propene into propane, a benchmark test for catalysis. They found the activated membranes "showed excellent and durable activity," according to the paper.

Co-authors of the paper include Pulickel Ajayan, Rice's Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science and of chemistry; primary author Niina Halonen, Aatto Rautio, Anne-Riikka Leino, Teemu Kyllönen, Jyrki Lappalainen, Krisztiçn Kordás, Géza Tóth, Mike Huuhtanen and Riitta Keiski of the University of Oulu, Finland; and András Sápi, Mária Szabó, Ákos Kukovecz, Zoltán Kónya and Imre Kiricsi of the University of Szeged, Hungary. Funding came from Rice University, Tekes, the Finnish Funding Agency for Technology and Innovation, and the Academy of Finland.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Niina Halonen, Aatto Rautio, Anne-Riikka Leino, Teemu Kyllo%u0308nen, Ge%u0301za To%u0301th, Jyrki Lappalainen, Krisztia%u0301n Korda%u0301s, Mika Huuhtanen, Riitta L. Keiski, Andra%u0301s Sa%u0301pi, Ma%u0301ria Szabo%u0301, A%u0301kos Kukovecz, Zolta%u0301n Ko%u0301nya, Imre Kiricsi, Pulickel M. Ajayan, Robert Vajtai. Three-Dimensional Carbon Nanotube Scaffolds as Particulate Filters and Catalyst Support Membranes. ACS Nano, 2010; 100406135641055 DOI: 10.1021/nn100150x

Cite This Page:

Rice University. "Nano-infused filters prove effective." ScienceDaily. ScienceDaily, 29 April 2010. <www.sciencedaily.com/releases/2010/04/100426151634.htm>.
Rice University. (2010, April 29). Nano-infused filters prove effective. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2010/04/100426151634.htm
Rice University. "Nano-infused filters prove effective." ScienceDaily. www.sciencedaily.com/releases/2010/04/100426151634.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) — TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) — Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) — When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:  

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile iPhone Android Web
          Follow Facebook Twitter Google+
          Subscribe RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins