Papers by Author: Lin Sun

Abstract: The factors that influence the performance of Bi₂₀TiO₃₂ were discussed, and the removal of TOC in the analogue waste water was also examined. The shorter the light wavelength or the more the intensity, the more efficient the photocatalytic process. Different substance has different optimum pH for being photodegraded by photocatalyst Bi₂₀TiO₃₂, which may be related with its surface charge. Aeration have little benefit for decomposing the organics. Some organics like methyl orange and phenol can be photodegraded by Bi₂₀TiO₃₂ completely. Bi₂₀TiO₃₂ has visible-light activity for the degradation of organics.

Abstract: This paper studied the stability and regeneration mechanism of photocatalyst Bi₂₀TiO₃₂. There is no change in the XRD of the catalyst after reaction, which indicates that photocatalyst Bi₂₀TiO₃₂ has stable structure. The comparison of XPS between used and fresh catalyst, shows that the major cause of the deactivation is the competitive adsorption of intermediates onto the surface active sites of the catalyst. Simple cleaning by deionized water, light irradiation, acid or base purging can not refresh the catalyst. However, ethanol with ultrasonic vibration can recover its activity well, as further demonstrates that the deactivation is because of that active sites are occupied by organic intermediates. Calcination is an effective way to recover the catalyst activity.

Abstract: In order to make full use of sunlight and improve photocatalytic degradation efficiency, a new rotary solar photocatalytic reactor with focus reflector was designed. The new type of solar photocatalytic reactor we designed solves such problems as shallow optical depth, small surface area, the need for aeration and agitation, insufficient contacting time or sunlight intensity in the photocatalytic reaction. It has the characteristics of cheap price and easy operation. Using focus reflector to increase the light intensity can improve decomposing efficiency. The paper also studied the method for the immobilization of the catalyst.

Abstract: Comparative research was done on the performance of new highly visible-light responsive photocatalyst Bi20TiO32 with P-25. Surface photovoltage spectrum of Bi20TiO32 indicates that its absorption wavelength starts from 550nm. Under Xe-lamp irradiation and the same catalyst dosage, the apparent rate constant of degrading methyl orange by P25 is 0.0465min-1, which is 2.7 times higher than that achieved by Bi20TiO32 (0.0172min-1). The apparent rate constant of degrading phenol by P-25 is 0.0543min-1, which is 1.8 times higher than that achieved by Bi20TiO32 (0.0296min-1). And the TOC removal of the solution by P-25 is also greater than by Bi20TiO32. But the performance of Bi20TiO32 under visible light irradiation is better than P-25. Under the visible light irradiation (>400nm), the apparent rate constant of degrading methyl orange by Bi20TiO32 is 0.0119min-1, which is 3.13 times higher than that achieved by P25 (0.0038min-1). The apparent rate constant of degrading phenol by Bi20TiO32 is 0.0133min-1, which is 33.25 times higher than that achieved by P-25 (0.0004min-1), and TOC removal by Bi20TiO32 is also much higher than by P-25.