Deacidification and reinforcement of aged paper by bacterial cellulose-borax composites via pressurized atomization

The acid-induced depolymerization of cellulose inevitably leads to severe embrittlement and mechanical failure in historical documents, creating an urgent need for effective restoration strategies. However, a major limitation of existing deacidification techniques is their inability to simultaneously restore the structural integrity of fragile paper while ensuring uniform protection. In the present work, a novel, controllable, and efficient strategy based on pressurized atomization of bacterial cellulose–borax (HBC) composites was proposed for the protection of paper documents. The deacidification treatment resulted in a substantial pH increase, from 3.84 to 7.46 (ΔpH = 3.62), accompanied by the formation of a dense bacterial cellulose membrane that cross-linked the fibers for enhanced strength. Meanwhile, borate ions formed hydrogen bonds with the hydroxyl groups of the cellulose fibers, contributing to the formation of a more integrated and reinforced fiber network. Furthermore, the deacidified paper exhibited improved mechanical properties, compared to the untreated paper: the breaking length increased from 1.263 km to 1.546 km, and the tear index rose from 2.103 to 2.965 mN·m 2 ·g -1 . Based on these findings, a practical pressurized-atomization device for BC–BX deacidification was assembled, and its effectiveness and overall feasibility were validated. This work establishes a practical pressurized-atomization deacidification strategy, offering a promising approach for the long-term preservation of historical paper documents.