Photocatalytic remediation of γ-hexachlorocyclohexane contaminated soils using TiO2 and montmorillonite composite photocatalyst

TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading γ-hexachlorocyclohexane(γ-HCH)in soils.After being spiked with γ-HCH,soil samples loaded with the composite photocatalysts were exposed to UV-light irradiation.The results indicated that the photocatalytic activities of the composite photocatalysts varied with the content of TiO2 in the order of 10%＜70%＜50%＜30%.Moreover,the photocatalytic activity of the composite photocatalysts with TiO2 content 30% was higher than that of the pure P25 with the same mass of TiO2.The strong adsorption capacity of the composite photocatalysts and quantum size effect may contribute to its increased photocatalytic activities.In addition,effect of dosage of composite photocatalysts and soil pH on γ-HCH photodegradation was investigated. Pentachlorocyclohexene,trichlorocyclohexene,and dichlorobenzene were detected as photodegradation intermediates,which were gradually degraded with tlle phOtOdegradation evolution.     

多级串联表面流库塘-湿地净化农田径流效果评价

农田径流已成为湖泊流域非点源污染治理的主要制约因素.为研究多级串联表面流库塘-湿地中各级表面流湿地对洱海流域农田径流水体的净化效果,以大理市喜洲镇美坝村新建的多级串联表面流库塘-湿地为研究对象,跟踪监测其各级表面流湿地进、出水中ρ（TN）、ρ（NO₃--N）和ρ（TP）,分析水质净化效果及营养盐质量浓度沿程变化规律.结果表明:①多级串联表面流库塘-湿地出水ρ（TN）、ρ（NO₃--N）和ρ（TP）平均值分别为1.77、1.18和0.05 mg/L,低于GB 3838—2002《地表水环境质量标准》中Ⅴ类标准限值,TN、NO₃--N和TP去除率分别为57.75%、65.54%和67.43%.②农田径流在经过沉淀池、一级和二级表面流湿地后,对TN、NO₃--N和TP的去除率已分别达45.35%、52.21%和50.59%,且二级表面流湿地中出水ρ（TN）、ρ（NO₃--N）和ρ（TP）分别为2.36、1.69和0.06 mg/L,已达到较好的出水水质.③氮、磷营养盐质量浓度沿程削减模型拟合结果表明,指数削减模型较适宜表征TN、NO₃--N在多级串联表面流库塘-湿地中的沿程削减过程,而TP的最佳削减模型为线性削减模型.研究显示,多级串联表面流库塘-湿地对农田径流具有较好的净化效果,其对营养盐净化作用主要体现在前两级表面流湿地.      

基于时间序列分析的渐变性水源水质预测研究

针对引黄水库水质渐变性特点,运用时间序列分析理论建立了水质分析模型并对山东省某市某水库的水质变化趋势进行模拟和预测。选取温度、pH、氨氮、浊度、化学耗氧量、亚硝酸盐作为预测变量。水库水质的模拟结果表明除浊度外其余项准确率均达到了80%以上,所建立的水质模型能够合理地反映渐变性水库中水质的动态变化趋势,预测结果较好。     

centrifugal用热控装置设计

目的 评估飞行器产品在飞行过程对热–离心综合环境的适应性,研制一套热–离心综合环境试验用热控装置。方法 从热–离心试验需求出发,完成综合试验系统总体研制目标及系统方案设计。针对高g值离心环境（离心加速度值≥90g）下的热载荷加载需求,开展基于热传导的热载荷加载方法研究,并完成适用于高g值环境的热控装置硬件布局优化设计。提出基于分段包络思想的产品响应温度梯度分布效应模拟方法及实现,减少过试验考核。结果 利用该热控装置完成了热–离心综合环境功能验证试验,设置最大加速度为92g,保载时间为3 min,最高加热温度为150℃,最大温升速率为3℃/min,3温区控制,升温过程中,温度误差优于±1.5℃。结论 该热–离心综合环境试验用热控装置可用于飞行器产品热–离心综合环境试验的考核。     

Cobalt and manganese stress in the microalga Pavlova viridis （Prymnesiophyceae）： Effects on lipid peroxidation and antioxidant enzymes

Pollution of marine environment has become an issue of major concern in recent years.Serious environmental pollution by heavy metals results from their increasing utilization in industrial processes and because most heavy metals are transported into the marine environment and accumulated without decomposition.The aim of the present study is to investigate the effects on growth,pigments, lipid peroxidation,and some antioxidant enzyme activities of marine microalga Pavlova viridis,in response to elevated concentrations of cobalt(Co)and manganese(Mn),especially with regard to the involvement of antioxidative defences against heavy metal-induced oxidative stress.In response to Co~(2 ),lipid peroxidation was enhanced compared to the control,as an indication of the oxidative damage caused by metal concentration assayed in the microalgal cells but not Mn~(2 ).Exposure of Pavlova viridis to the two metals caused changes in enzyme activities in a different manner,depending on the metal assayed:after Co~(2 )treatments,total superoxide dismutase(SOD)activity was irregular,although it was not significantly affected by Mn~(2 )exposure.Co~(2 )and Mn~(2 )stimulated the activities of catalase(CAT)and glutathione(GSH),whereas,ghitathione peroxidase(GPX)showed a remarkable increase in activity in response to Co~(2 )treatments and decreased gradually with Mn~(2 )concentration,up to 50μmol/L,and then rose very rapidly,reaching to about 38.98% at 200μmol/L Mn~(2 ).These results suggest that an activation of some antioxidant enzymes was enhanced,to counteract the oxidative stress induced by the two metals at higher concentration.     

改进折流式生物反应器净化洗浴废水

利用改进折流式生物反应器，研究了好氧渐变厌氧交替工艺对洗浴废水中氮、磷和有机污染物的去除效果。结果表明：洗浴废水中COD和BOD值分别从98.0-190.6mg/L和68.3-81.7mg/L下降到6-10mg/L和1-2mg/L，含氮化合物和含磷化合物的浓度则分别从13．5—25．2mg/L和9．9—13．5mg／L下降到1mg/L和0．5mg／L。在运行过程中，不需要添加甲醇，利用洗浴废水自身的有机物就能达到很好的脱氮、除磷和降解COD与BOD的效果，而且该工艺的动力消耗仅为传统活性污泥法的三分之一。     

Effects of hydrodynamics processes on phosphorus fluxes from sediment in large, shallow Taihu Lake

The turnover of phosphorus （P） in lake sediments, a major cause of eutrophication and subsequent deterioration of water quality, is in need of deep understanding. In this study, effects of resuspension on P release were studied in cylindrical microcosms with Yshape apparatus. The results indicated that there was a positive correlation between flux of suspended substance across sediment-water interface （Fss） and the wind speed, and an increasing Fss during each wind process followed by a steady state. The maximal Fss under fight, moderate, and strong wind conditions were 299.9±41.1,573.4±61.7, and 2093.8±215.7 g/m^2, respectively. However, flux of P across sediment-water interface （Fp） did not follow a similar pattern as Fss responding to wind intensity, which increased and reached the maximum in initial 120 rain for fight wind, then decreased gradually, with maximal flux of 9.4±1.9 mg/m^2. A rapid increase of Fp at the first 30 rain was observed under moderate wind, with maximal flux of 11.2±0.6 mg/m^2. Surprisingly, strong wind caused less Fp than under light and moderate wind conditions with maximal flux of 3.5±0.9 mg/m^2. Fss in water column declined obviously during the sedimentation process after winds, but Fp varied with wind regime. No obvious difference was detected on Fp after 8 h sedimentation process, compared with the initial value, which means little redundant P left in the water column after winds.