Fe3O4/Ag磁性纳米颗粒去除水中的铅离子

采用水相共沉淀法制备小尺寸磁性Fe₃O₄纳米颗粒,以没食子酸作为还原剂和表面修饰剂,还原Ag[(NH₃)₂]⁺制备出Fe₃O₄/Ag磁性纳米颗粒。研究该磁性纳米颗粒对水溶液中铅离子的吸附行为,研究结果表明,pH为7.0,吸附温度30℃时可得到最好的处理效果,铅的去除率可达99.7%以上,Fe₃O₄/Ag颗粒吸附行为符合二级动力学模型(R² > 0.99)。该磁性纳米颗粒经过多次再生处理后,仍具有很好的吸附效果,表明Fe₃O₄/Ag在水处理方面拥有良好的应用前景。     

间歇运行式生物滴滤池处理油漆废气中试研究

为研究间歇运行式生物滴滤池对油漆生产厂废气净化能力,建立一座中试规模生物滴滤池（BTF）,接种降解菌群,采用8 h/d运行方式净化某油漆厂包装车间废气,并用PCR-DGGE技术揭示BTF细菌群落结构与工艺运行条件间的联系。油漆厂包装车间废气中挥发性有机物（VOCs）主要为甲苯、乙苯、混合二甲苯（间、对和邻二甲苯）,BTF对甲苯、乙苯、混合二甲苯最大去除率分别为88.8%、83.7%和86.3%。DGGE分析显示,BTF稳定运行时,主要优势菌相对丰度较为稳定（F,P>0.05）,其细菌多样性显著低于启动期（F,P>0.05）;同时,下层填料细菌多样性高于上层填料,其细菌结构变化也较上层明显;另外,提升培养液浓度至2倍和4倍对菌群结构亦无显著影响。     

响应面分析法优化稀土废水MAP沉淀法脱氮

经过预处理后的稀土生产废水,其氨氮浓度大幅降低,但并未达到中华人民共和国《稀土工业污染物排放标准》（GB26451-2011）中氨氮浓度限值。实验通过响应面分析法中的Box-Behnken实验设计（BBD）,取pH、n（Mg）：n（N）、n（P）：n（N）3因素,采用Design-Expert 8.0.6,建立合适的剩余氨氮浓度及剩余总磷浓度模型,得到回归方程,并分析模型各项指标,各因素及其相互作用对剩余氨氮浓度及剩余总磷浓度的影响。利用预测模型预测最佳实验条件,在最佳实验条件下验证预测结果,并对沉淀物进行X射线衍射（XRD）分析。结果显示,二次响应模型适用于剩余氨氮浓度及剩余总磷浓度,2个模型均拥有较好的拟合程度、可信度及精密度,最优反应条件为：pH=9.88、n（Mg）：n（N）=1.50：1、n（P）：n（N）=1.38：1时,剩余氨氮浓度为46.58 mg/L,剩余总磷浓度为7.85 mg/L。在最优条件下所得到的沉淀物并非纯净的MgNH₄PO₄·6H₂O,还有Mg₃（PO₄）₂·22H₂O生成。     

臭氧-BAF组合工艺对石化行业废水深度处理的中试研究

采用臭氧-曝气生物滤池（BAF）组合工艺对中石化九江分公司二级生化出水进行深度处理中试实验。探讨了臭氧投加量、进水水质冲击负荷等因素对该组合工艺出水COD、NH₄⁺-N的影响。中试结果表明,在该水质条件下,臭氧最佳投加量为20~25 mg/L;组合工艺处理后出水COD低于40 mg/L,NH₄⁺-N低于5 mg/L,达到中水回用设计标准;该组合工艺能够经受一定冲击负荷。     

Projecting Climate Change Effects on Forest Net Primary Productivity in Subtropical Louisiana,USA

This study projected responses of forest net primary productivity (NPP) to three climate change scenarios at a resolution of 5 km × 5 km across the state of Louisiana, USA. In addition, we assessed uncertainties associated with the NPP projection at the grid and state levels. Climate data of the scenarios were derived from Community Climate System Model outputs. Changes in annual NPP between 2000 and 2050 were projected with the forest ecosystem model PnET-II. Results showed that forest productivity would increase under climate change scenarios A1B and A2, but with scenario B1, it would peak during 2011–2020 and then decline. The projected average NPP under B1 over the years from 2000 to 2050 was significantly different from those under A1B and A2. Forest NPP appeared to be primarily a function of temperature, not precipitation. Uncertainties of the NPP projection were due to large spatial resolution of the climate variables. Overall, this study suggested that in order to project effects of climate change on forest ecosystem at regional level, modeling uncertainties could be reduced by increasing the spatial resolution of the climate projections.     

Chlorination of chlortoluron: kinetics, pathways and chloroform formation

Chlortoluron chlorination is studied in the pH range of 3-10 at 25 ± 1 °C. The chlorination kinetics can be well described by a second-order kinetics model, first-order in chlorine and first-order in chlortoluron. The apparent rate constants were determined and found to be minimum at pH 6, maximum at pH 3 and medium at alkaline conditions. The rate constant of each predominant elementary reactions (i.e., the acid-catalyzed reaction of chlortoluron with HOCl, the reaction of chlortoluron with HOCl and the reaction of chlortoluron with OCl⁻) was calculated as 3.12 (± 0.10) × 10⁷ M⁻² h⁻¹, 3.11 (±0.39) × 10² M⁻¹ h⁻¹ and 3.06 (±0.47) × 10³ M⁻¹ h⁻¹, respectively. The main chlortoluron chlorination by-products were identified by gas chromatography-mass spectrometry (GC-MS) with purge-and-trap pretreatment, ultra-performance liquid chromatography-electrospray ionization-MS and GC-electron capture detector. Six volatile disinfection by-products were identified including chloroform (CF), dichloroacetonitrile, 1,1-dichloropropanone, 1,1,1-trichloropropanone, dichloronitromethane and trichloronitromethane. Degradation pathways of chlortoluron chlorination were then proposed. High concentrations of CF were generated during chlortoluron chlorination, with maximum CF yield at circumneutral pH range in solution.     

Analysis of pesticide residues using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) pesticide multiresidue method in traditional Chinese medicine by gas chromatography with electron capture detection

The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 15 organochlorine pesticides (OCPs) in completely different matrices of traditional Chinese medicine (TCM). The method employed a rapid, simple and cost-effective procedure. The spiking levels for the recovery experiments were 0.1, 0.5 and 2.0 mg kg⁻¹. Mean recoveries mostly ranged between 76.0% and 114.0% (96.0% on average), and relative standard deviations (RSD) were generally below 10% (4.72% on average). Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity. The contamination status of 15 OCPs on 80 different TCMs marketed in China, and a total of 400 samples were also performed using a previously validated method. 15 OCPs were benzene hexachloride (BHC, including α-BHC, β-BHC, γ-BHC, δ-BHC), hexachlorobenzene, heptachlor, heptachlor epoxide, aldrin, p, p′-DDE, p, p′-DDD, o, p′-DDT, p, p′-DDT, mirex, endrin, dieldrin. This study indicates that the proposed method is useful for analyzing OCPs in TCM.     

钛基IrO2-SnO2电极在烟气海水脱硫恢复系统中的应用

采用浸渍-热分解法制备了含IrOx-TiO2中间层的IrO2-SnO2电极,得到的电极具有较高的析氯电催化活性和较强的稳定性,并通过电化学氧化法对Na2SO3海水脱硫模拟液进行处理,考察了电流密度、温度、pH值和电解时间等电解工艺参数对Na2SO3去除率和化学需氧量COD的影响.结果表明,在电流密度为200 mA/cm...     

低温等离子体氧化水中难降解有机物研究

实验将介质阻挡放电与电晕放电组合在同一个反应器内,实验废水为直接大红染料溶液,将高压电极上通人50 Hz交流高压电,介质阻挡放电系统的电极间距为30 mm、电晕放电系统电极间距为25 mm、电源电压20 kV,利用常压空气中形成的雾化水电极介质阻挡放电/电晕放电低温等离子体及其活性基团作用于难降解有机物分子.实验分析了...