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991.
大型溞(Daphnia magna)因其个体小、繁殖快、易于培养及对污染物敏感等特点,而成为水生毒理学研究中广泛应用的模式物种.本文构建了一套以大型溞为受试动物的水生生态毒理学实验内容和方案,可用于本科生基础性、综合性实验教学.本方案以形态学观察、生理学和毒理学测试为主,也可扩展为包括分子毒理学在内的其他毒性终点的创新性实验.此外,授课教师还可以本方案为基础,对实验内容酌情增减或联合使用,以满足不同层次学生的生态毒理学实验需求.  相似文献   
992.
中国南方土壤常常受到镉砷复合污染,镉砷的化学特性截然不同,因此在土壤不同组分表面的化学行为存在显著区别。在南方偏酸性土壤中铁氧化物占固相比例很大,基于此,选取两种典型土壤组分,即铁氧化物(针铁矿)和微生物(蜡状芽孢杆菌Bacillus cereus),通过批吸附实验结合X-射线光电子能谱探究Cd(Ⅱ)与As(Ⅴ)的共吸附特点和潜在机制,得到如下结果:在单一体系中,针铁矿对As(V)的亲和力较强,Langmuir模型拟合得到最大吸附量为1259.82 mmol·kg-1,而蜡状芽孢杆菌对Cd(Ⅱ)的亲和力较强,最大吸附量可达1291.64 mmol·kg-1。XPS结果表明,针铁矿表面铁羟基和细菌表面羧基和酰胺/胺基在Cd(Ⅱ)、As(Ⅴ)吸附过程中发挥主导作用;在Cd(Ⅱ)-As(Ⅴ)复合体系中,可能形成吸附剂-Cd-As或吸附剂-As-Cd三元络合物。该研究证实,镉砷在典型土壤铁氧矿物体系中的吸附存在普遍的促进效应,在微生物体系中存在不同程度的抑制,Cd(Ⅱ)与As(Ⅴ)的共吸附规律在土壤矿物和微生物上存在区别,这也意味着在土壤根际土壤与非根际土壤中有较大差异。因此在预测土壤Cd(Ⅱ)、As(Ⅴ)共存规律时也要考虑土壤组成,特别是有机物的含量等因素。该研究结果可为预测镉、砷在土壤组分上的迁移转化行为提供参考,为调控镉砷形态,对预测镉、砷在土壤中的生物地球化学循环有一定的参考价值。  相似文献   
993.
• Cu0.15-ACF performs the best for H2S and PH3 simultaneous removal. • 550°C and 90°C are separately calcination and reaction temperatures. • The reason why Cu0.15/ACF shows better performance was found. • The accumulation of H2PO4 and SO42−(H2O)6 is the deactivation cause of Cu0.15/ACF. Poisonous gases, such as H2S and PH3, produced by industrial production harm humans and damage the environment. In this study, H2S and PH3 were simultaneously removed at low temperature by modified activated carbon fiber (ACF) catalysts. We have considered the active metal type, content, precursor, calcination, and reaction temperature. Experimental results exhibited that ACF could best perform by loading 15% Cu from nitrate. The optimized calcination temperature and reaction temperature separately were 550°C and 90°C. Under these conditions, the most removal capacity could reach 69.7 mg/g and 132.1 mg/g, respectively. Characterization results showed that moderate calcination temperature (550°C) is suitable for the formation of the copper element on the surface of ACF, lower or higher temperature will generate more cuprous oxide. Although both can exhibit catalytic activity, the role of the copper element is significantly greater. Due to the exceptional dispersibility of copper (oxide), the ACF can still maintain the advantages of larger specific surface area and pore volume after loading copper, which is the main reason for better performance of related catalysts. Finally, increasing the copper loading amount can significantly increase the crystallinity and particle size of copper (oxide) on the ACF, thereby improving its catalytic performance. In situ IR found that the reason for the deactivation of the catalyst should be the accumulation of generated H2PO4 and SO42−(H2O)6 which could poison the catalyst.  相似文献   
994.
生态环境重大工程是实施国家中长期规划、具有中国特色的一项制度安排。本研究通过梳理我国重大生态环境工程项目管理现状,包括制度建设、工程标准体系建设、绩效管理体系建设等,结合“十四五”生态环境保护形势和任务要求,分析当前我国在生态环境工程项目管理体系建设上存在的主要问题。在此基础上,构建出我国重大生态环境项目组织管理的框架和路线图,提出“十四五”加强和提升我国重大生态环境保护项目全过程管理的对策与建议。  相似文献   
995.
2019年天津市挥发性有机物污染特征及来源   总被引:13,自引:13,他引:0  
为了解天津市环境空气挥发性有机物(VOCs)污染特征及来源,基于2019年城区点位高时间分辨率在线监测数据,对天津市VOCs浓度水平、化学组成及来源进行分析.结果表明,2019年天津市VOCs年均浓度为48.9 μg·m-3,不同季节浓度水平依次为:冬季(66.9 μg·m-3) > 秋季(47.9 μg·m-3) > 夏季(42.0 μg·m-3) > 春季(34.6 μg·m-3).化学组成包括烷烃、芳香烃、烯烃和炔烃,年均浓度占比分别为:65.0%、17.4%、14.6%和3.0%,其中烷烃、芳香烃和炔烃占比分别在秋季、夏季和冬季最高,烯烃占比在夏季和冬季均较高.春夏季烷烃、烯烃、芳香烃和炔烃的臭氧生成潜势贡献分别为:16.9%、48.6%、33.5%和1.0%,乙烯、丙烯、间/对-二甲苯、1,2,3-三甲苯、甲苯、异戊二烯、反-2-丁烯、顺-2-戊烯、邻-二甲苯和间-乙基甲苯的臭氧生成潜势较高;秋冬季芳香烃对二次有机气溶胶(SOA)生成潜势贡献高达91.5%,邻-二甲苯、甲苯、间/对-二甲苯、乙苯、邻-乙基甲苯和苯是主要贡献物种.PMF解析结果表明,春夏季VOCs主要来源分别为:机动车排放源、LPG/NG和汽油挥发源、溶剂使用源、石化工业源、燃烧源和天然源,贡献率分别为:29.2%、19.9%、16.4%、10.3%、7.3%和6.6%;秋冬季VOCs主要来源分别为:LPG/NG和汽油挥发源、机动车排放源、燃烧源、溶剂使用源和石化工业源,贡献率分别为:32.4%、21.9%、18.5%、13.3%和8.4%.与春夏季相比,秋冬季VOCs来源中LPG/NG和燃烧源贡献率分别显著上升62.8%和153.4%,其他源贡献率下降18.4%~25.0%.结合解析得到的各源类成分谱结果,春夏季石化工业源和溶剂使用源排放以烯烃和芳香烃为主,为臭氧防控重点管控对象;秋冬季燃烧源和溶剂使用源排放芳香烃类物质较多,为SOA重点防控源.  相似文献   
996.
被动采样-UV法测定环境空气中的臭氧浓度   总被引:2,自引:0,他引:2  
研究被动采样-UV法测定臭氧浓度.以NaNO2作为诱捕试剂,用被动采样器吸收O3,然后在紫外分光光度计上进行测定.通过测定所生成的NO-3浓度,间接计算出臭氧浓度.结果表明,测得臭氧浓度范围在20~100 μg/m3,NO-3浓度线性范围在0~0.6 mmol/L.在测定NO-3浓度时,NO-2会造成很大的干扰,但在实验中,NO-2浓度在0~0.8 mmol/L,氨基磺酸都能有效地去除其干扰.该方法是简单、灵敏、可靠的测定环境空气中臭氧浓度的良好方法.  相似文献   
997.
RSM was utilized to optimize and model influential parameters on fluoride removal. Regression models involving independent variables and main response were developed. Interactive effects and optimum of process factors were illuminated and determined. Fluoride removal efficiency of 99.69% was observed in optimal process conditions. Response surface methodology was utilized to model and optimize the operational variables for defluoridation using an electrodialysis process as the treatment of secondary effluent of the graphite industry. Experiments were conducted using a Box-Behnken surface statistical design in order to evaluate the effects and the interaction of the influential variables including the operational voltage, initial fluoride concentration and flow rate. The regression models for defluoridation and energy consumption responses were statistically validated using analysis of variance (ANOVA); high coefficient of determination values (R2 = 0.9772 and R2 = 0.9814; respectively) were obtained. The quadratic model exhibited high reproducibility and a good fit of the experimental data. The optimum values of the initial fluoride concentration, voltage and flow rate were found to be 13.9 mg/L, 13.4 V, 102.5 L/h, respectively. A fluoride removal efficiency of 99.69% was observed under optimum conditions for the treatment of the secondary effluent of the graphite industry.  相似文献   
998.
柳焜  王黎  胡宁  陈小进  廖梦根 《化工环保》2012,40(2):169-174
采用微生物电合成系统(MES)还原CO2合成有机物,从微生物菌群、有机物积累量、库伦效率、电化学分析等多个角度研究了阴极电势对MES还原CO2合成有机物性能的影响。实验结果表明:阴极电势为-0.70 V时,甲酸和乙酸的积累量均最大(分别为1.554 mmol/L和2.754 mmol/L),系统的总库伦效率最大(为81.42%);在MES中,醋杆菌(Acetobacterium sp.)、假丝酵母菌(Candida sp. S)、地杆菌(Geobacter sp.)为优势菌种。  相似文献   
999.
Wise and sustainable uses of water resources are essential for an effective river-basin-management planning. Recent management strategy further addresses the fact that quantity and quality of water are closely interrelated, and both must be considered simultaneously for all water resources and water quality management practices. The aim of this paper is to explore the impacts of water resources redistribution and pollution prevention actions between and within river basins simultaneously in South Taiwan. Much emphasis will be placed on assessing the impacts of water transfer over natural boundary to satisfy the needs of industrial development in the Tseng-Wen River system and its resultant influence on the water quality in the downstream area of the Kao-Ping River system where the pollution prevention program is to be implemented. The Kao-Ping River was further characterized hydraulically and environmentally, based on a full investigation of discharges and withdrawals in the river reaches. QUAL2E was successfully calibrated and validated using data collected between 1998 and 1999, and the model was capable of predicting the concentrations of biochemical oxygen demand, dissolved oxygen, total phosphate-phosphorus, and ammonia-nitrogen (NH3-N) for the entire river system. With the aid of QUAL2E simulation model, it shows eliminating the pig farming activities and constructing the sewer systems in the upstream area of Kao-Ping River cannot guarantee the full compliance with water quality standards in the downstream area and water transfer in the upstream area further increases negative impacts on the water quality in the wet season. The predicted situation of water quality in the dry season may even present worse condition. Additional water pollution control policy, such as the use of economic instruments, for controlling and reducing the waste-load of biochemical oxygen demand and ammonia-nitrogen is needed in the Kao-Ping River system in the long run.  相似文献   
1000.
苯系混合气体生物滴滤器净化性能研究   总被引:1,自引:0,他引:1  
马红  羌宁  季学李 《四川环境》2005,24(2):24-26,53
本研究采用纤维附着活性炭(ACOF)和不锈钢丝网为载体材料,进行了气体生物滴滤器(BTF)净化TEX(甲苯、乙苯、二甲苯)混合气体的动态实验研究。实验结果表明最大消除能力值在140g/m3·h左右。由于载体材料的特殊结构和性能,实验研究中实现了对TEX这类疏水性物质在较少停留时间和较大空塔气速情况下的高效连续运行。高负荷运行时,会由于过剩生物质积累引起装置堵塞、压降增加,但设备净化效果变化不显著。  相似文献   
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