Chemical Engineering December 2011 - 15

CHEMENTATOR
Recover oil from messy spills
with this mesh
novel mesh for oil-water separation
with opposite wettability to traditional
materials has been developed by a group
of researchers from Beijing, China - the
Beijing National Laboratory for Molecular
Sciences, Institute of Chemistry, Chinese
Academy of Sciences (www.iccas.
ac.cn); School of Chemistry and Environment,
Beihang University (ev.buaa.edu.
cn); Dept. of Chemistry, Tsinghua University
(www.tsinghua.edu.cn); and Graduate
School of the Chinese Academy of Sciences
(gucas.ac.cn).
The new material is a superhydrophilic
and underwater superoleophobic hydrogelcoated
mesh in an oil/water/solid threephase
system. It consists of rough nanostructured
hydrogel coatings and microscale
porous metal substrates. The researchers
claim the new material can selectively and
with an efficiency of better than 99%, separate
water from oil-water mixtures, such
as vegetable oil, gasoline, diesel, and even
crude-petroleum oil-water mixtures withA
out
any extra power. The underwater superoleophobic
interface prevents the coated
mesh from fouling by oil, making it easy to
recycle the oil and the materials.
Hydrogel consists of a cross-linked network
with interstitial spaces that fill up
with water, making it a typical hydrophilic
material. The trapped water molecules
greatly decrease the contact area between
oil droplet and solid surface. The threephase
system presents a discontinuous contact
line, allowing an oil droplet to easily
roll off the surface, and the oil-adhesion on
the surface is extremely low.
The research group chose polyacrylamide
(PAM) as the coating material, where
N,N'-methylene bisacrylamide (BIS) served
as the chemical cross-linker.
Stainless
MT HalfpgChemEng2011.qxd:Chemical Engineering /2 horizontal 11/1/11 1:25 PM Page 1
steel meshes with diameters between 340
and 380 µm were used as substrates. The
cleaned stainless-steel mesh was carefully
immersed in the mixed pre-gel solution,
then drawn out horizontally and slowly
(Continues on p. 16)
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Circle 21 on p. 62 or go to adlinks.che.com/35072-21
CHEMICAL ENGINEERING WWW.CHE.COM DECEMBER 2011 15
Green standards
In late October, NFS International
(Ann Arbor, Mich.;
www.nsf.org) and the American
Chemical Soc. Green
Chemistry Institute (ACS
GCI; Washington, D.C.; www.
acs.org/gci) developed an
American National Standard
that provides a standardized
way to define and report the
environmental and human
health hazards associated
with a chemical product and
its manufacturing process
impacts. The standard,
known as NSF/GCI/ANSI
255 Greener Chemicals
and Process Information
Standard (www.nsf.org/info/
nsfgci355), establishes standardized
criteria for comparing
chemicals and processes
that help manufacturers
and their customers make
" greener " choices. As a thirdparty
certifier, NSGF International
will certify reports to
this standard.
❏

http://www.nsf.org http://www.acs.org/gci http://www.iccas http://www.ac.cn http://ev.buaa.edu http://www.tsinghua.edu.cn http://gucas.ac.cn http://www.nsf.org/info/ http://www.multitherm.com http://adlinks.che.com/35072-21 http://WWW.CHE.COM

Chemical Engineering December 2011

Table of Contents for the Digital Edition of Chemical Engineering December 2011