Study On Preparation And Performance Of Paper Containing Titanium Dioxide

Over the past several decades, photocatalytic degradation of indoor volatile organic pollutants (VOC) by titanium dioxide (TiO2) had attracted much attention. In this paper, actived carbon fibers (ACF) were used as the nano-TiO2 carrier, and the ACF/TiO2 photocatalytic sheet was prepared by a papermaking technique in an attempt to offer technological and theoretical support for the research of photocalytic paper.A simple photocatalytic device to test formaldehyde concentration was designed using resistance-type semiconductor VOC sensor. This device not only had good air tightness, but also was stable and sensitive. The detection results showed that the sensor sensitivity and concentration of formaldehyde is presented inverse logarithm relationship.The synergistic effect of ACF and nano-TiO2 was tested, the results indicated that the first and second time using ACF sheet, TiO2 sheet and ACF/TiO2 sheet, the photocatalytic dagradation rate were 65%/15%, 80%/80%, 90%/89%. We found that the ACF/TiO2 sheet could overcome the saturation of ACF sheet and increase the degradation rate of TiO2 sheet. With 30% and 35°SR softwood pulp, the ACF/TiO2 ratio of 1:2, 6% latex, 0.15% PEI and 0.2% APAM, the tensile index, retension rate of TiO2, air permeability and photocatalytic degradation rate can reach about 4.7N·m/g,94%, 2000mL/min, 94% respectively.To prepare stable TiO2 suspension in water, the optimal dispersion treatment parameters were as following: the pH<3.0 or pH>9.5, Ultra sonic dispersion time 15 min, amount of sodium hexametaphosphate 0.2%. And the ACF base sheet was prepared with 2% PPE to increase the wet strength. After dipping, the dipped sheet with 6g/m2 TiO2 can degrade 84% formaldehyde after 210 min. By the way, the TiO2 added in the wet-end sheet can degrade 93% formaldehyde after 210 min. The SEM images showed nano-TiO2 distributed uniform on the ACF about the dipped sheet, while the nano-TiO2 filled in the goove of ACF about the wet-end sheet, but both methods could improve the contact area.Some factors, such as the photocatalytic activity of photocatalyst, lamps, light intensity, concentration of formaldehyde, and humidity, were researched. And the results showed that the photocatalytic activity of photocatalyst is the key point to degrade formaldehyde efficiently; the degradation rate of 254nm, 365nm, and incandescent lamp were 99%, 99%, 55%, this means the incandescent lamp hardly photocatalytic degaraded formaldehyde; the increasing speed of photocatalytic degradation became slower and slower as increasing the light intensity; the lower concentration of formaldehyde was fit for zero order reaction, while the higher concentration was fit for first order reaction; the photocatalytic degradation rate was highest when the humidity remain about 45%.