Study On Determination Of Hydrogen Peroxide And Its Application In Photocatalytic Oxidation

In this thesis, a new method for determination of hydrogen peroxide using a modified ion chromatograph based on the flow injection analysis principle was developed. Three sets of automatic and continuous mornitoring systems for controlling the concentration of HaCh during water treatment were designed. Dye wastewater and phenol wastewater were treated with photocatalytic oxidation. During the reaction of phenol wastewater the residual concentrations of H2O2 were determined using the new method. According to the relationship between the residual H2O2 and the reaction efficiency, mechanism of photocatalytic reaction of TiOi was discussed.1 A study on the determination of hydrogen peroxide based on the flow injection analysis-conductivity method with a modified ion chromatographA new method for the determination of hydrogen peroxide using a modified ion chromatograph with a conductometric detector based on the flow injection analysis principle was developed. In this study HjSOj is used as carrier liquid which reacts with HzOz to produce H2SO4 and the conductivity change between FfeSCb and H2SO4 has a good linearity with the concentration of hydrogen peroxide. The results showed the repeatability of 8 times was less than 2.6%, the lowest detectable concentration was 0.5mg/L and the relationship coefficient was 0.9996. The effects of H^SOs concentration, injection volume, reactor length on the results were also discussed. In order to eliminate the interference of the conductivity of other ions in water catalase was used to decompose the I-bC^ for the blank.2 Design of automatic and continuous mornitoring systems for controlling the concentration of H2O2 during water treatment2.1 Automatic and continuous mornitoring system for controlling the concentration of HjOi with conductometric detectorAccording to the study of the determination of hydrogen peroxide using flow injection?.analysis-conductometric method, an automatic and continuous mornitoring system for controlling the concentration of HaOa with conductometric detector was designed. A ual-channel flow system with a dual-cell conductometric detector is utilized. In onechannel the enzyme catalase is added, which selectively destroys hydrogen peroxide before the oxidation reaction between HiOz and HiSOs. This channel therefore provides an analytical blank for the determination of hhOj. There is no enzyme catalase in another channel. The difference of these two signals is recorded simultaneously by the system. The whole system is run automatically by means of peristaltic pumps.2.2 Automatic and continuous mornitoring system for controlling the concentration of HjOz with fluorometric detectorThis technique is based on the selective catalysis of H2O2 which can react with(p-hydroxyphenyl) acetic acid (POPHA) and produce a dimeric product(6,6'-dihydroxy-3,3'-biphenyldiacetic acid). The dimeric product has strong fluorescencewith a peak excitation wavelength of 320 nm and a peak emission wavelength of 400 nm.The peroxide concentration is directly proportional to the fluorescence intensity.Peroxidase also catalyzes the reaction of organic hydroperoxides to form the fluorescence dimmer. In order to distinguish HiOi from organic hydroperoxides, a dual-channel flow system with a dual-cell fluorometer is utilized, hi one channel the enzyme catalase is added, which selectively destroys hydrogen peroxide before the peroxide-catalyzed reaction occurs. This channel therefore provides an analytical blank for the determination of HaC^. There is no enzyme catalase in another channel. The difference of these two signals is recorded simultaneously by the system. The whole system is run automatically by means of peristaltic pumps.2.3 Automatic and continuous mornitoring system for controlling the concentration of HjOa with chemiluminescent detectorIt is reported that KIO/rK^COa system which produces strong chemiluminescent signals can be used to determine HaC^. It...