A new environmentally benign technology and approach to bleaching kraft pulp. Polyoxometalates for selective delignification and waste mineralization

A new technology based on polyoxometalates for bleaching and processing wood pulp in conjunction with paper manufacture is presented. In four Unit Operations not only is kraft pulp selectively delignified by polyoxometalates in an anaerobic process, but also all organic waste from the bleaching step is mineralized to CO2 and H2O by polyoxometalates in a complex aerobic process. The sum of the Unit Operations is the selective conversion of kraft pulp into a bleached pulp with attractive papermaking profiles (strength indices, mechanical properties, etc.), plus CO2 and H2O. Studies using dimeric lignin models link lignin fragmentation during anaerobic polyoxometalate delignification to a combination of oxidative and hydrolytic steps.