Chemical Engineering July 2021 - 7

Embedding active enzymes into plastics
R
esearchers at the Fraunhofer Institute
for Applied Polymer Research
(IAP;
Potsdam-Golm,
www.iap.fraunhofer.de)
Germany;
have
developed
a process for embedding active enzymes
into plastics. This has been difficult before,
since plastics are normally processed at
temperatures above 100°C. The technology
offers the possibility of manufacturing materials
that clean themselves, have anti-mold
surfaces or are self-degrading, for example.
The new materials are being developed
as part of a project running since summer
2018, in cooperation with The Brandenburg
University of Technology (BTU; Cottbus-Senftenberg,
Germany).
In order to stabilize the enzymes, the researchers
use porous inorganic carriers.
" The enzymes bind to these carriers by
embedding in the pores, " explains Ruben
R. Rosencrantz, head of the Biofunctionalized
Materials and (Glyco)Biotechnology
department at Fraunhofer IAP. " Although
this restricts the enzymes' mobility, they remain
active and are able to withstand much
higher temperatures, " he says.
The researchers then found a way to
apply the stabilized enzymes not only to
the surface of the plastic, but of embedding
them into the plastics directly. In order
to achieve an optimum material result in
the downstream process, the stabilized
enzymes have to be distributed as quickly
Fraunhofer IAP
as possible in the hot plastic melt to which
they are added, without becoming exposed
to excess force or elevated temperatures.
" We have developed a process that is suitable
for both bioplastics and for conventional
petroleum-based plastics such as
polyethylene, " says Thomas Büsse who
heads the institute's processing pilot plant
for biopolymers in Schwarzheide.
So far, the researchers have mainly evaluated
protease enzymes, which are able to
break up other proteins. This lends the plastic
functionalized by these proteases a selfcleaning
effect. Pipes, for example, would not
close up or clog as readily. Other enzymes
are also being systematically tested as well.
The partners at BTU Cottbus-Senftenberg
are focusing more closely on enzymes for
degrading plastics and toxic substances,
for example. The first functionalized plastic
granulates, films and injection molding bodies
have already been produced in a pilot
plant in Schwarzheide (photo).
Scaling up a recycling process for
blended textile fibers
I
n order to handle the growing volume
of waste textile materials, recycling processes
must begin significantly scaling
up. Lenzing AG (Lenzing, Austria; www.
lenzing.com) and Södra (Växjö, Sweden;
www.sodra.com) are joining forces to scale
up the OnceMore textile-recycling process,
which is said to be the world's first industrial-scale
recycling technology for textiles
with blended fibers, which are typically
seen as difficult to efficiently recycle.
" OnceMore is able to simultaneously degrade
polyester while retaining the cotton
or cellulosic part of the material. Today,
the process accepts textiles containing
up to 50% polyester. Since polyestercotton
is one of the most abundant textile
blends, we can process many types
of post-consumer waste, including bedsheets,
napkins, towels and garments, "
explains Johannes Bogren, vice president
of Södra's Cell Bioproducts division. Furthermore,
OnceMore is capable of largescale
production because it is able to use
existing pulp-mill equipment says Bogren.
The process blends waste textiles with
wood cellulose to create a dissolving highalpha-cellulose
pulp product that can be
processed into new textile products. The
OnceMore technology has successfully
processed 25 tons of textile waste in one
day, and the company is now working
to replicate that performance and begin
using OnceMore pulp as a raw material for
the production of Lenzing's Tencel x Refibra
specialty fibers.
Lenzing and Södra's partnership aims to
increase the share of recycled content in
OnceMore pulp from 20% up to 50%, significantly
increasing the production capacity.
" For our target of recycling 25,000 tons
of textiles by 2025, we will need a working,
sorting and collecting system for discarded
textiles. People need to stop throwing their
textile waste in the garbage. Technologywise,
we need to expand our specification
for what we can accept - we will need
ways to handle zippers, prints, various trims
and assorted fibers like wool, elastane and
nylon, " adds Bogren.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM JULY 2021
is based on Axens' PrimeG+
hydrodesulfurization
technology and Sulzer
Chemtech's GT-BTX PluS
extraction technology.
The combination of Prime
G+ and GT-BTX PluS offers
a unique solution to reduce
octane loss to a very low
level for the gasoline pool.
The technology is especially
important in countries
that are upgrading fuel
specifications to meet environmental
requirements,
and it can be applied in
new, or retrofits of existing
units in operation to maximize
profit. It also provides
refiners the option of converting
FCC gasoline into
petrochemical products
- benzene, toluene, xylenes
(BTX) and additional
propylene - and get additional
margin in regions
where gasoline demand is
not sufficient. For those, the
combined offer can convert
their excess gasoline into
petrochemical products to
adapt to the market change
with minimum investment,
say the companies.
TRANSPORTING H2O2
Evonik Industries AG (Essen,
Germany; www.evonik.com)
has developed a container
made of pure aluminum with
a 220-L capacity for the safe
transport of high-concentration
hydrogen peroxide.
With this patented container,
the company is closing a logistical
gap that had opened
up in the safe delivery of
highly concentrated H2O2
to users in the aerospace
industry. Up to now, only
very small containers (up to
12.5 L) were available.
The new container is installed
in a lattice box with
a protective steel frame
to protect the actual container
from damage during
transport. The pure aluminum
in the inner tank
serves to ensure the quality
of the H2O2.
H2O2 in concentrations of
82.5 to 98% has been used
as a propellant for rocket
engines since the mid-20th
century. With Propulse,
Evonik is supplying a highconcentrated
H2O2 for this
(Continues on p. 8)
7
http://www.iap.fraunhofer.de http://www.evonik.com http://www.lenzing.com http://www.sodra.com http://WWW.CHEMENGONLINE.COM
Chemical Engineering July 2021

Table of Contents for the Digital Edition of Chemical Engineering July 2021
