The Impact Of Mass Transfer Effects On The TiO₂ Photocatalytic Material In The Flow State Of Water

With the increased awareness of environmental protection, environmental requirements for water are increasingly high, urgent need of new wastewater treatment technologies and key technologies. In particular, the difficult type of biodegradable organic compounds containing chlorine, has a significant human and biological harm. After a large number of academic studies have shown that, TiO2 as a cheap photo catalytic material has a significant effect in chloroform removal. But when it is reaction of metallic iron with chloroform removal, is a new lecture recently.This issue mainly through two different flow conditions, complete mixing flow and plug flow, study the mass transfer effects of TiO2 photo catalyst in different conditions, and then causing changes in the removal of chloroform.In the first, established two experimental systems corresponding to two kinds of flow state, and then change the status of some of the parameters of two flows, to study the effect of changes in mass transfer, and then get the basis of the change in the removal of chloroform, mainly conclusion are:1. The best removal of chloroform in complete mixing flow is 52.72%, but in simulate plug flow is 24.55%, the complete mixing flow experiment response to stabilize need two hours, but the simulate plug flow need a half of two hours, so the experiment result of complete mixing flow is better than plug flow.2. In the complete mixing flow reactor, as a strong mechanical agitation so that the liquid turbulence, enhanced mass transfer is also conducive to the chemical reaction. In the experiment, mass transfer coefficient base in the liquid mass transfer coefficient. The two different experiment base solution are distilled water and tap water, the mass transfer coefficient are 5.66×10-4m/s and 8.52×10-4m/s, consistent with the removal in the two experiment are 41.54% and 52.25%.3. In the plug flow reactor, when Re<2000, affect the mass transfer is mainly molecular diffusion. Experimental results that in three kinds of velocity, 2.16×10-2m/s,1.54×10-2m/s,7.77×10-3m/s, little change in diffusion coefficient, bur with the reduced of flow rate, the mass flux reduced too, the data are 7.69×10-5g/ m2·s,6.02×10-5 g/ m2·s,4.52×10-5 g/ m2·s. Then with the velocity increase, mass transfer enhancement, the removal of chloroform increased.