不同质量浓度苦草对铜绿微囊藻生长及抗氧化酶系统的影响

采用苦草（Vallisneria spiralis Linn.）和铜绿微囊藻（Microcystis aeruginosa）共生培养的实验方法,通过追踪测定铜绿微囊藻的生物量、叶绿素a含量、丙二醛（MDA）含量、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性,研究了不同质量浓度苦草对铜绿微囊藻生长及抗氧化酶系统的影响。结果表明,质量浓度大于10 g/L时,苦草对铜绿微囊藻有明显的抑制作用,表现为苦草质量浓度为10、20和40 g/L时,第15天对铜绿微囊藻的抑制率分别为63.3%、94.7%和99.8%,培养过程中,铜绿微囊藻的叶绿素a含量逐渐减少,而SOD、POD活性及MDA含量呈现先增加后逐渐降低的趋势,表明苦草释放的化感物质在经过一定时间积累后能够明显抑制铜绿微囊藻SOD和POD的活性,引起细胞的氧化损伤,促进叶绿素的分解,从而导致藻类死亡,这是苦草抑制铜绿微囊藻生长的原因之一。     

Degradation of rizazole in water–sediment systems

This study investigated the degradation of rizazole in water-sediment systems (West Lake system, WL; Beijing–Hangzhou Grand Canal system, BG) with two different types of sediments under aerobic and anaerobic conditions. The half-lives of rizazole in the WL water phase (14.59–15.13 d) were similar to those in the BG water phase (15.90–16.46 d). Within 3–7 d, the rizazole concentration in the sediments reached the maximum values, i.e., equilibrium. Rizazole dissipation was faster in the WL sediment phase with higher organic matter content (T_1/2 = 18.99–19.09 d) compared with the BG sediment phase (T_1/2 = 31.08–33.32 d). Rizazole degradation was slightly faster in the West Lake water-sediment system (WL system) (T_1/2 = 17.11–18.05 d) than in the Beijing–Hangzhou Grand Canal water—sediment system (BG system) (T_1/2 = 20.51–25.02 d). The aerobic degradation of rizazole was similar to its anaerobic degradation in the water-sediment system. The findings are useful to understand the behavior of pesticide in environment.     

H(+)/phenanthrene symporter and aquaglyceroporin are implicated in phenanthrene uptake by wheat (Triticum aestivum L.) roots

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that are toxic to human and nonhuman organisms. Dietary intake of PAHs is a dominant route of exposure for the general population because food crops are a major source of dietary PAHs. The mechanism for crop root uptake of PAHs remains unclear. Here we reveal that wheat root uptake of PAHs involves active and passive processes. The passive uptake is mercury and glycerol dependent. Mercury and glycerol inhibit uptake, indicating that aquaglyceroporins sensitive to mercury contribute to passive uptake. Active uptake is mediated by a phenanthrene/H symporter. The electrical response of wheat roots triggered by phenanthrene consists of two sequential phases: depolarization followed by repolarization. The depolarization is phenanthrene concentration dependent, with saturation kinetics that have an apparent of K(m) 10.8 μmol L(-1). As uptake proceeds, external solution pH increase is noticed. Lower pH favors the uptake. Vanadate and 2,4-dinitrophenol suppress the electrical response to phenanthrene and phenanthrene uptake, suggesting that plasma membrane H(+)-ATPase is involved in the establishment of an electrochemical proton gradient acting as a driving force for active uptake. Therefore, it is suggested that aquaglyceroporin and phenanthrene/H symporter are implicated in phenanthrene uptake. Our results provide insight into PAH uptake mechanism in wheat roots that is relevant to strategies for reducing PAH accumulation in wheat for food safety, improving phytoremediation of PAH-contaminated soils or water by agronomic practices and genetic modification to target remedial plants for higher PAH uptake capacity.     

季节性城市生活垃圾成分分析及厌氧消化特性研究

城市生活垃圾的成分及特性随着季节和人类在不同季节的生活习惯而变化,针对我国北方城市研究了一年中不同季节的城市生活垃圾成分特点,对影响厌氧发酵过程的相关成分如总有机碳（TOC）、总氮（TN）、蛋白质、脂肪和还原糖等进行了测定分析。通过厌氧消化实验,测得不同季节城市生活垃圾pH值、日产气量、沼气甲烷含量、甲烷累积量、挥发性脂肪酸（VFAs）和氧化还原电位（ORP）等参数的变化规律,分析相应变化的影响因素。结果表明,二、三季度的含水率分别为64．81％和67．50％,高于一、四季度,一季度发酵原料中蛋白质和脂肪含量分别为12．56％和8．86％,明显高于其他3个季度。一季度甲烷累积量最高,达到17616mL,单位发酵原料的产气量为204．8mL／g,也是4个季度中最高的,说明蛋白质、脂肪等有机成分含量对厌氧发酵过程及结果影响比较明显。为进一步的城市生活垃圾厌氧消化制取生物燃气的工艺条件提供依据。     

轻污油罐运行风险分析与对策

结合轻污油罐发生的典型事故案例,分析了轻污油罐运行过程中存在的浮盘冲顶、油罐撕裂、管线断裂、火灾、爆炸、中毒窒息等风险,剖析了事故的原因,提出了增加轻污油闪蒸系统等对策.     

g-C3N4/TiO2纳米管阵列光阳极的制备及其光电催化降解邻氯硝基苯

采用阳极氧化-涂覆煅烧法成功制备了g-C₃N₄/TiO₂纳米管阵列（g-C₃N₄/TNAs）光阳极,并通过扫描电镜、X射线衍射仪、X射线光电子能谱仪、紫外可见漫反射光谱仪、光致发光光谱仪和电化学工作站等表征分析了g-C₃N₄/TNAs光阳极的形貌、晶形结构、光学特性和光电化学性能.表征结果证实,g-C₃N₄的引入通过缩小禁带宽度扩宽了TNAs的可见光响应范围,提高了光电流密度和光生电子寿命,促进了光生电子和空穴的分离.g-C₃N₄/TNAs光阳极在光电催化体系内对邻氯硝基苯（o-CNB）的降解效率高于其在光催化和电催化体系中对o-CNB的降解效率,且具有良好的稳定性和可重复性.活性物质捕获实验、电子自旋共振测试和能带结构分析表明,g-C₃N₄/TNAs光阳极中TNAs和g-C₃N₄之间存在Z型异质结相互作用机制.在光电催化体系内降解o-CNB的主要活性物质是^?O₂^-、^?OH和光生空穴,而光生电子是次要的活性物质.     

Photodegradation of amoxicillin by catalyzed Fe3+/H2O2 process

Three oxidation processes of UV-Fe³⁺(EDTA)/H₂O₂ (UV: ultraviolet light; EDTA: ethylenediaminetetraacetic acid), UV-Fe³⁺/H₂O₂ and Fe³⁺/H₂O₂ were simultaneously investigated for the degradation of amoxicillin at pH 7.0. The results indicated that, 100% amoxicillin degradation and 81.9% chemical oxygen demand (COD_Cr) removal could be achieved in the UV-Fe³⁺ (EDTA)/H₂O₂ process. The treatment efficiency of amoxicillin and COD_Cr removal were found to decrease to 59.0% and 43.0% in the UV-Fe³⁺/H₂O₂ process; 39.6% and 31.3% in the Fe³⁺/H₂O₂ process. Moreover, the results of biodegradability (biological oxygen demand (BOD₅)/COD_Cr ratio) revealed that the UV-Fe³⁺ (EDTA)/H₂O₂ process was a promising strategy to degrade amoxicillin as the biodegradability of the effluent was improved to 0.45, compared with the cases of UV-Fe³⁺/H₂O₂ (0.25) and Fe³⁺/H₂O₂ (0.10) processes. Therefore, it could be deduced that EDTA and UV light performed synergetic catalytic effect on the Fe³⁺/H₂O₂ process, enhancing the treatment efficiency. The degradation mechanisms were also investigated via UV-Vis spectra, and high performance liquid chromatography-mass spectra. The degradation pathway of amoxicillin was further proposed.     

Fenton试剂在处理难降解有机废水中的应用

介绍了Ferton试剂的作用机理,探讨了不同外界因素对该技术处理效果的影响,对该试剂在实际中的应用进行阐述。并提出Fenton试剂的研究方向。     

工业锅炉环境污染控讨与控制

对工业锅炉运行中造成环境污染的因素及危害进行分析,结合实际,制定了减少危害的措施。