[Investigation of the oxidation reaction of O3 with bromide ion in aqueous solution].

The reaction mechanism of O3 with bromide ion in aqueous solution was studied by ion chromatography and UV-Vis spectrometry instruments. Ion chromatography analysis showed that only 10% of Br- which was oxidized by ozone was formed into bromate ion. The results demonstrated that the final products of the oxidation reaction were identified as Br2 and Br3- except for BrO3-. The formation of Br3- which was yielded from the reaction of Br2 with Br- was the major process in the reaction of Br attacked by O3. The characteristic absorption spectrum of Br3- with an absorption peak at 260 nm was also investigated. The results may provide helpful information about the mechanism of the oxidation reaction of Br- with O3 and fate of Br- or its derivatives in the environment by the oxidation processes.

[New-type electrodeless excilamp for advanced treatment on nitrogen-heterocyclic compounds (NHCs) in aqueous solution].

A novel 206 nm excilamp generated by microwave-driven Kr/I2 mixtures was employed for nitrogen-heterocyclic compounds (NHCs) degradation in aqueous solution. The photodissociation efficiencies of indole and quinoline with 206 nm excilamp were estimated on the basis of removal efficiency of targeted compounds and the loss of total organic carbon (TOC). The results indicated that removal efficiency of 20 mg x L(-1) indole was as high as 62.0% after 80 min and TOC loss efficiency of 50.7% for 150 min. The irradiation time, initial concentration and pH value had some influences on quinoline degradation. Indole removal efficiency and TOC loss was markedly higher than that of quinoline under the same condition. The intermediates were identified qualitatively by gas chromatography/mass spectrum (GC/MS) with headspace sampling after they were extracted by rotary evaporator. GC/MS analysis indicated that indole and quinoline underwent ring-open dissociation under 206 nm irradiation, as a result, benzene, xylene, acetate, aldehyde, as well as ester compounds were formed, while indole aggregation reaction occurred during indole photodegradation. At last, degradation mechanisms of quinoline and indole in aqueous media with 206 nm excilamp were proposed on the basis of intermediates.

[Photolysis of simulating CS2 malodorous gas using microwave electrodeless lamps].

The photolysis of simulating carbon disulfide malodorous gas was studied under UV irradiation emitted by microwave electrodeless lamps. Experiments results show that the photolysis of carbon disulfide is determined by the initial concentration, residence time and gas humidity. When air velocity is 0.2 m/s, initial concentration is about 100 mg/m3, and gas humidity is about 40%, the conversion ratio of carbon disulfide can reach to 75% with microwave electrodeless mercury lamp and 50% with microwave electrodeless iodine lamp. The mechanism of carbon disulfide photolysis was further studied. It is concluded that the photolysis of carbon disulfide is probably a collective action of direct photolysis and *OH radical oxidation.

A combined plasma photolysis (CPP) method for removal of CS2 from gas streams at atmospheric pressure.

A combined plasma photolysis (CPP) reactor that utilizes a dielectric barrier discharge (DBD) plasma and 207 nm UV radiation from discharge-driven KrBr* excimers was designed and constructed. Gas streams containing CS2 were treated with stand-alone DBD and CPP at atmospheric pressure. In comparison to DBD, CPP greatly enhanced the removal efficiency at the same applied voltage, waste gas concentration and gas residence time. Thus the applied voltage could be reduced to a certain extent in the plasma processing of industrial wastes. Influences of the KrBr* radiation, inlet CS2 concentration and gas residence time on CS2 removal by CPP were also studied. In addition, the likely reaction mechanisms for the removal of CS2 by CPP are suggested based on the byproducts analysis. The enhanced removal efficiency and reaction mechanisms implied that the CPP process would probably be suitable for the removal of a large number of gaseous pollutants.

[Photocatalytic degradation of hexafluorobenzene by tungstophosphoric acid].

We verified that C6F6, a typical perfluorine compound, could be photocatalytic degraded by H3PW12O40. The defluorination of C6F6 was determined as a function of irradiation time, pH, initial concentration of H3PW12O40, and additives as well. The defluorination of C6F6 increased with the irradiation time. Acid condition, especially pH = 1.0 is preferred. 3 mL solution of 2.0 x 10(-4) mol/L C6F6 and 5.0 x 10(-6) mol/L H3PW12O40 was irradiated for 20 min and the defluorination of C6F6 was equal to 208.1%. O2, KMnO4 and K2S2O8 added in the solution were able to increase the defluorination of C6F6 via oxidating [PW12O40](4-). The defluorination of C6F6 would decline in the presence of alcohol and aromatic compounds.

[Differentiated thyroid carcinoma in children and adolescents: clinical characteristics and treatment].

OBJECTIVE: To explore the clinicopathologic characteristics, treatment and prognosis of differentiated thyroid carcinoma (DTC) in adolescents. METHODS: The data of 46 patients with DTC under the age of 18 years were retrospectively reviewed. RESULTS: Twenty patients were misdiagnosed in this group (43.5%). All patients received operation, including 39 unilateral neck dissection and 6 bilateral neck dissection, followed by postoperative thyrotropin suppressive therapy. There were 42 cases of papillary carcinoma (91.3%) and 4 cases of follicular carcinoma (8.7%). Cervical lymph node metastasis was found in 39 cases (84.8%). In the follow-up period of 1 to 25 years (mean 10 years), no death of thyroid carcinoma occurred. CONCLUSIONS: The most common DTC in adolescents is papillary carcinoma with better prognosis regardless of the higher incidence of cervical lymph node metastasis. The optimal extent of primary thyroidectomy and neck dissection followed by postoperative thyrotropin suppressive therapy in adolescents with DTC may improve the quality of life and decrease the incidence of complications.

[Dissociation of SF5CF3 under discharge].

SF5CF3 was identified recently as a potent greenhouse gas with strong radiative force and long atmosphere residential life. Spark discharge method was used to take simulative investigation on the elimination of SF5CF3 from atmosphere under discharge here. The results show that SF5CF3 was dissociated under discharge and formed some compounds containing S, F, O and C. The dissociation of SF5CF3 was reduced if the system existed H2O, but it was independent of the amount of H2O. The rate coefficients were estimated to be 0.011s(-1) under moisture circumstance when the system total pressure was about 31 kPa. And the increase of the system pressure would cause exponential decrease of SF5CF3 dissociation. The reactive mechanism was argued based on the experiment results and the sinks of SF5CF3 under lightning (one of the discharge in the atmosphere) was estimated to be 53.6 kg x a(-1).