Paper machine manufactured photocatalysts - Lateral variations

Paper machine manufacturing of photocatalysts can enable low cost devices for removal of low concentrated pollutants. Lateral variations originating from the paper making process leads to variations of the catalytic activity over the paper area. Paper machine manufactured papers made from tetrapodal ZnO whiskers and kraft pulp were investigated in this test geometry using simulated solar light. Photocatalytic ZnO papers were laminated between polyethylene sheets and an indicator solution seeped into the laminated photocatalytic paper, to create a test geometry where the indicator ink is confined to a small volume between the polyethylene sheets. The photocatalyst papers exhibited surprisingly similar photocatalytic behavior although having different catalyst loading 15, 30 and 45 wt percent. All papers exhibited lateral variations that peaked during the conversion. The results show that production of effective photocatalytic composite papers can be scaled. Further, the results show that variations must be considered for photocatalytic papers.