Photochemical oxidation of thiophene in n-octane/water extraction system by using air as oxidant was studied.Results obtained here can be used as the reference of oxidative desulfurization of gasoline because thiophene is one of the main sulfur-containing components in fluid catalytic cracking gasoline.A 500 W high pressure Hg lamp （wave length 365 nm, 0.19 kW·m -2 ） was used as the light source for irradiation and air was introduced by a gas pump for supplying O2.Thiophene dissolved in n-octane was photodecomposed and removed into the water phase at ambient temperature and atmospheric pressure.Thiophene can be photo-oxidized directly to sulfone,sulfoxide, or ethanedioic acid,SO 2- 4 ,CO2.The photo-oxidation kinetics of thiophene with O2 was first-order with rate constant of 4.42×10 -5 s -1 and half-time of 4.36 h.The desulfurization yield of thiophene in n-octane was 58.9% for a 5 h photo-irradiation under the conditions with air flow at 150 ml·min -1 and water/oil ratio at 1∶1.The sulfur content could be reduced from 800 μl·L -1 to less than 330 μl·L -1 .
通过对某污水处理厂循环活性污泥法工艺(cyclic activated sludge technology,CAST)中选择池、缺氧池和好氧池中氮组分和污泥浓度进行测定,结合污泥活性、同步硝化-反硝化(simultaneous nitrification and denitrification,SND)速率及饱食-饥饿(feast-famine)批次实验,评价该处理工艺的脱氮性能。结果表明,好氧池内同步硝化-反硝化和沉淀过程中的内源反硝化(endogenous denitrification,ED)脱氮对总氮去除的贡献占据主导,分别为(35.50±4.15)%和(62.86±4.13)%,而缺氧池反硝化(DEN)脱氮贡献仅为(1.64±0.05)%;溶解氧(dissolved oxygen,DO)浓度对CAST工艺脱氮性能有极大影响,控制好氧池中DO浓度为1~1.5 mg·L^(-1)时可获得最佳脱氮效果,CAST工艺的TN去除率可达84.51%;饱食-饥饿批次实验证明,饥饿时长为36 h时对乙酸(HAc)的吸收能力最强,可达每1 g VSS消耗0.173 g HAc,依此可推算出CAST工艺的最佳回流比为45%。
