Paper's Brighter Future
The use of chlorine for bleaching and processing wood pulp to make paper is
one of industry's dirtiest environmental practices, producing various
highly toxic pollutants, including dioxin. Cleaner methods are available
but chlorine has several big advantages; it's cheap and it works well. Now
a chemist at Carnegie Mellon University has developed a family of
iron-based catalysts that could make one of the leading chlorine
alternatives-hydrogen peroxide-more commercially attractive.
Small amounts of the catalysts, called TAML (tetraamido-macrocyclic ligand
activators), greatly speed up the hydrogen peroxide bleaching process and
allow it to take place at 50 C or even room temperature. What's more, the
catalysts make hydrogen peroxide far more effective in "delignification," a
key step for making high-quality paper. Terrence Collins, a chemist at CMU
and developer of the technology, says industry is already testing the
peroxide activators; he expects that the technology will be ready for
commercial papermaking within three years.
