Enzymes were adsorbed on the silica mesoporous materials FSM-16, MCM-41, and SBA-15 with various pore diameters from 30 to 90Ä and their stabilities were studied. FSM-16 and MCM-41 prepared by a cationic surfactant showed a higher adsorption of HRP than SBA-15 prepared using a nonionic surfactant. When the average mesopore size of FSM-16 just matched the molecular diameters of the enzyme, immobilized HRP exhibited the best stability. Both the surface character and size matching between pore sizes and the molecular diameters of HRP were important in achieving a high stability. Manganese peroxidase (MnP) immobilized in FSM-16, whose pore size just matched the diameter of the enzyme, showed the best stability and high H₂O₂ tolerance. A two-stage reactor system (TSRS) involving the MnP-immobilized FSM-16 was constructed in which the enzyme and pulp bleaching reactions were separately performed. The thermally discontinuous TSRS resulted in efficient pulp bleaching. After treatment of pulp with TSRS, the brightness of pulp increased to about 85% within 6h.

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