Immobilization of TiO@d2 nanoparticles onto paper modification through bioconjugation

TiO@d2 is commonly used as a brightening agent for paper, but may also be used on paper as a photocatalyst. The TiO@d2 aggregates that typically form in/on paper are inefficient both for brightening or photooxidation. We describe, for the first time, the preparation of homogeneously distributed, non-aggregated TiO@d2 particles on cellulose fibers using explicit bioconjugation with the fusion protein of CBM2a-@@iStrep@-tag II/streptavidin/biotinylated TiO@d2. The maximum absorption of proteins and nanoparticles onto paper were determined to be @@ica.@ 6.22 x 10@@u-2@ nm@@u-2@ for CBM2a-@@iStrep@-tag II, 1.93 x 10@@u-2@ nm@@u-2@ for streptavidin, and 58 km@@u-2@ for TiO@d2 nanoparticles, respectively. The efficiency of photocatalysis of the TiO@d2-containing paper prepared by this bioconjugation method was demonstrated by the decolorization of UV sensitive dye (reactive black dye 5). Immobilized TiO@d2 efficiently degraded the dye within about 10 hours. Only after extensive photolysis (12 hours) did sufficient degradation of the bioconjugating linkers occur such that free TiO@d2 particles and cellulose fibers were found in the supernatant. These experiments demonstrate that bioconjugation of TiO@d2 to paper leads to an effective, supported photocatalyst system.