改性甘蔗渣吸附废水中低浓度Cu2+的研究

利用离子液氯化-1-己基-3-甲基咪唑对甘蔗渣进行改性,利用改性甘蔗渣吸附去除模拟废水中低浓度的Cu2+,并对比了较优条件下甘蔗渣改性前后的Cu2+吸附性能.结果表明,溶液pH、改性甘蔗渣投加量、吸附时间对改性甘蔗渣吸附Cu2+均有一定的影响,较佳的溶液pH为5.41、改性甘蔗渣投加量为0.30 g、吸附时间为130 min;吸附温度升高Cu2+吸附率反而降低,因此选择在室温下进行吸附反应为宜;在以上较优条件下,改性甘蔗渣和甘蔗渣的Cu2+吸附率分别为83.20％和53.83％,前者的Cu2+吸附率提高了30.35％.     

An assessment of heavy metals loading in River Benue in the Makurdi Metropolitan Area in Central Nigeria

River Benue, the second largest river in Nigeria, serves as the major source of municipal water supplies for towns and villages along its course. Water samples from the river were collected at ten stations in the Makurdi metropolitan area (7°44^′ N, 8°32^′ E) in Benue State, Central Nigeria, for 12 months and analyzed for their heavy metals concentration, along with other water-quality parameters such as turbidity, pH, total dissolved solids and total solids. The results revealed that the mean concentrations of heavy metals in the river was in the following ascending order, Cd < Cu < Zn < Mn < Pb < Cr < Fe. The levels of most of the parameters determined, with the exception of Cd, Cr and Pb were, generally, within acceptable limits for drinking water. From the present study, it is concluded that the River Benue is only moderately contaminated with regard to heavy metals, in the Makurdi metropolitan area.     

城市工业区周边土壤-水稻系统中重金属的迁移累积特征

对H市工业区土壤-稻米-谷壳体系中重金属的迁移累积特征进行分析,结果显示,不同重金属元素的迁移累积特征不同,Cd易于从土壤中向稻谷籽实迁移,而Cu,Zn,Cr,Ni,As和Hg等迁移能力则较弱.水稻籽实中不同重金属在稻米和谷壳之间的分配规律不同.营养元素Cu和Zn有向稻米迁移累积的趋势,而有毒有害重金属Pb,Cd,Cr,Ni和As则主要累积于谷壳中,Cr和Nj在稻米和谷壳之间的分配较均衡.重金属在稻米中的累积能力为:Cd>Zn>Ni>Cu>Pb>Cr>Hg>As,而在谷壳中则为:Cd>Pb>Ni>Zn>Cr>Cu>As>Hg.     

Dispersive liquid–liquid microextraction of silver nanoparticles in water using ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate

Using the ionic liquid(IL)1-octyl-3-methylimidazolium hexafluorophosphate as the extractant and methanol as the dispersion solvent,a dispersive liquid–liquid microextraction method was developed to extract silver nanoparticles(AgN Ps)from environmental water samples.Parameters that influenced the extraction efficiency such as IL concentration,pH and extraction time were optimized.Under the optimized conditions,the highest extraction efficiency for AgN Ps was above 90% with an enrichment factor of 90.The extracted AgN Ps in the IL phase were identified by transmission electron microscopy and ultraviolet–visible spectroscopy,and quantified by inductively coupled plasma mass spectrometry after microwave digestion,with a detection limit of 0.01 μg/L.The spiked recovery of AgN Ps was 84.4% with a relative standard deviation(RSD)of 3.8%(n = 6)at a spiked level of 5 μg/L,and 89.7% with a RSD of 2.2%(n = 6)at a spiked level of 300 μg/L,respectively.Commonly existed environmental ions had a very limited influence on the extraction efficiency.The developed method was successfully applied to the analysis of Ag NPs in river water,lake water,and the influent and effluent of a wastewater treatment plant,with recoveries in the range of 71.0%–90.9% at spiking levels of 0.11–4.7 μg/L.     

生物沸石球强化吸附氨氮废水的动力学研究

用一种具有多孔结构特征的沸石球作为载体固定化硝化细菌强化吸附氨氮废水。结果表明,沸石球能快速固定化硝化细菌,吸附动力学表明150 min对氨氮吸附容量达到2.816 mg/g,而且还有继续增加的趋势。假二级动力学方程和Elovich模型的精确拟合说明,生物沸石球对氨氮的吸附过程可能是非均相扩散起作用及以化学吸附反应为主的复杂转化过程。扩散拟合结果表明,氨氮在生物沸石球的吸附是以液膜扩散和颗粒内扩散为吸附速率的控制步骤,活性的硝化细菌对氨氮的硝化使氨氮在微孔的吸附得到了强化。     

污水处理厂中邻苯二甲酸酯类环境激素分析

建立了基于HLB固相萃取柱和液相色谱分析城市污水中邻苯二甲酸酯类环境激素的方法 ,同时分析了北京市 4个污水处理厂进水与出水中邻苯二甲酸酯类环境激素的浓度。在四个污水处理厂的水样中共检出了 5种邻苯二甲酸酯 ,分别是DEP、BBP、DBP、DCHP和DEHP ,浓度在 0 .72～ 59.1 7μg/L之间。结果表明 ,曝气活性污泥法对大部分邻苯二甲酸酯类环境激素的去除效果很好     

Enhancing sensitivity of microbial fuel cell sensors for low concentration biodegradable organic matter detection: Regulation of substrate concentration, anode area and external resistance

The relatively low sensitivity is an important reason for restricting the microbial fuel cell (MFC) sensors’ application in low concentration biodegradable organic matter (BOM) detection. The startup parameters, including substrate concentration, anode area and external resistance, were regulated to enhance the sensitivity of MFC sensors. The results demonstrated that both the substrate concentration and anode area were positively correlated with the sensitivity of MFC sensors, and an external resistance of 210 Ω was found to be optimal in terms of sensitivity of MFC sensors. Optimized MFC sensors had lower detection limit (1 mg/L) and higher sensitivity (Slope value of the linear regression curve was 1.02), which effectively overcome the limitation of low concentration BOM detection. The essential reason is that optimized MFC sensors had higher coulombic efficiency, which was beneficial to improve the sensitivity of MFC sensors. The main impact of the substrate concentration and anode area was to regulate the proportion between electrogens and nonelectrogens, biomass and living cells of the anode biofilm. The external resistance mainly affected the morphology structure and the proportion of living cells of the anode. This study demonstrated an effective way to improve the sensitivity of MFC sensors for low concentration BOM detection.     

企业突发环境事件应急预案存在的问题与对策

查阅了2019年通过评审并备案的390家企事业单位突发环境事件应急预案,总结了企事业单位突发环境事件应急预案存在的问题及对策.为提高应急预案的适用性,应在准确辨识企业的环境风险物质、详细调查企业的周边环境风险受体情况、建立快速的应急监测机制、储备足够的应急物资等方面基础上,使应急措施和方案达到可操作性,凸显应急预案的使...     

管理措施对黄土高原油松人工林土壤水溶性碳氮及其三维荧光特征的影响

为研究不同管理措施(凋落物去除、油松幼林、灌木和草地)下土壤水溶性碳、氮含量的变化以及土壤溶解性有机质(SDOM)的组分,选取黄土高原油松人工林为研究对象,以未皆伐油松人工林作为对照,对土壤水溶性碳、氮以及SDOM荧光组分等相关重要特征量进行研究分析.结果表明,灌木和油松幼林的土壤水溶性有机碳含量显著高于其他管理措施,并且土壤水溶性有机碳含量随土层深度的增加而降低,土壤水溶性有机碳/土壤有机碳(WSOC/SOC)值随深度增加呈上升趋势;土壤水溶性氮含量的变化和水溶性碳的变化趋势一致,油松幼林土壤水溶性氮组分含量高于其他管理措施,总体上随深度的增加而降低.不同管理措施对SDOM组分影响显著,基于三维荧光光谱技术结合平行因子(EEM-PARAFAC)分析可知SDOM有4种组分,主要分为类腐殖质、类蛋白和可溶性微生物代谢产物三大类,其中SDOM的主要成分为富里酸类腐殖质,油松幼林土壤中富里酸含量最高.本研究表明,管理措施对土壤水溶性碳氮含量变化和SDOM组分具有一定的影响,特别是油松幼林和灌木影响较大.两种管理措施提高了土壤水溶性有机碳以及水溶性氮组分的含量,增强其在土壤中的迁移转化能力,同...