Degradation Of Azo Dye 4bs By Novel Photocatalytic Ultrafiltraion Memebrane Reactor

Azo dyes usually compose of aromatic or naphthalene rings which can not be degraded completely by conventional technologies.The discharge of incompletely degraded azo dyes wastewater would easily lead to tremendous danger because of its carcinogenic and teratogenic to aquatic lives and human being.Performance of novel slurry photocatalytic ultrafiltration membrane reactor on degradation of direct scarlet 4BS in dying wastewater was studied in this paper.Influence of operating parameters such as pH value,dose of titanium dioxide(TiO₂) and initial concentration of 4BS on photocatalysis process,as well as effect of feed velocity and operating time on PAN700 and PVDF700 ultrafiltration membrane separation,was investigated in detail.To analyze the adsorption and photocatalytic process of the 4BS,Langmuir model was introduced.Results indicated that a maximal adsorption of dye on TiO₂ occurred at pH 5.5 and the adsorption character was accorded with Langmuir model. Under the optimal condition of UV=100W,T=20℃,dose of TiO₂ at 1.0g·L^-1 and initial concentration of 4BS of 50 mg·L^-1,the decoloration rate of 4BS after irradiation of 60min was up to 97.9%,and the mineralization rate showed a similar rate by UV-Visible spectrum and TOC value.Effect of the feed velocity and operating time on two kinds of membranes was also checked.PAN700 showed a larger permeate flux and better anti-pollution behavior than PVDF700.The characteristic constantβfor each membrane was calculated according to the cake filtration model and found that PAN700 was more suitable than PVDF700 for coupling system.