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 (CMU) 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.