New catalyst could bring cleaner paper.
New catalyst means greener paper is not pulp fiction.
Pollution from paper production could be cut, say US chemists, with a new way of refining wood pulp1. But the process must go through the mill before it can convert industry.
During paper production, gluey wood component lignin is stripped out to leave stringy cellulose. The harsh chemicals used create environmental pollutants, such as toxic and long-lasting chlorinated compounds.
Paper manufacturing is one of the world’s largest industries. It generates 100 million tonnes of wood pulp a year. Using strong chemicals and high temperatures, pulping digests up to 90% of the lignin from wood chips. The resulting slurry is made into low-quality paper such as brown grocery bags.
For premium white paper, pulp is bleached and the remaining lignin is degraded using chlorine or the more environmentally friendly substitute, chlorine dioxide. These chemicals selectively break down lignin rather than cellulose by stealing its electrons, in an ’oxidation’ reaction. The new catalyst replaces this step.
The catalyst - called a polyoxometalate (POM) - was inspired by a protein in wood-digesting fungi. First, POM oxidizes lignin. Then oxygen re-oxidizes POM. This second step converts lignin to harmless carbon dioxide and water and recycles the catalyst.
At the end of the process, the catalyst must be carefully removed to avoid traces ending up in the paper. POM contains the heavy metals tungsten and molybdenum, also of concern to environmentalists.
Although this is "clever chemistry", says Terry Collins of Carnegie Mellon University in Pittsburgh, Pennsylvania, "it’s important that people keep experimenting with alternative technologies".
The inefficiency of the reaction means that 170 tonnes of catalyst are needed for every tonne of wood pulp, points out Collins, who works on green chemistry. This ratio would make working with the catalyst an expensive operation. He feels that new processes should aim to be cheap, efficient and non-toxic.
Weinstock argues that these criteria can be met and that the process can be made economically competitive.
HELEN PEARSON | © Nature News Service
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering