模拟退火算法在大气环境质量综合评价中的应用

为了建立一种对多项指标都能普遍使用的大气环境质量综合评价模式,利用模拟退火算法对幂函数加和型指数评价中参数进行优化,并用优化后的综合评价指数公式对大气环境进行综合评价。该公式应用于大量实例的分析评价结果与其他多种评价方法评价结果比较表明:该公式不受污染物种类和数目多少的限制,计算简便,具有可行性、实用性和通用性。     

Global fallout Pu recorded in lacustrine sediments in Lake Hongfeng, SW China

Studies on the distribution and isotope compositions of fallout Pu are important for source characterization of possible future non-fallout Pu contamination in aquatic environments, and useful for dating of recent sediments to understand the pollution history of environmental contaminants. We present the historical record of atmospheric Pu fallout reconstructed from a sediment core from Lake Hongfeng, China. The Pu activity profile was in agreement with the 137Cs profile. Inventories were 50.7 Bq m(-2) for 239+240Pu and 1586 Bq m(-2) for 137Cs. The average 240Pu/239Pu atom ratio was 0.185+/-0.009, indicating that Pu originated from global stratospheric fallout rather than from direct tropospheric or close-in fallout from the Chinese nuclear testing conducted in the 1970s. Our data suggested that Lake Hongfeng would be an ideal setting for monitoring atmospheric fallout and environmental changes in this region.     

Cadmium stress alters gene expression of DNA mismatch repair related genes in Arabidopsis seedlings

Cadmium (Cd) is a non essential element, and is a widespread environmental pollutant. Exposure to Cd can result in a variety of adverse health effects in plant and humans. In the current study, Arabidopsis seedlings were used as a bio-indicator of Cd pollution. Seedlings were grown on MS media containing 0-6.0 mg L(-1) Cd for 18 days, and the gene expression patterns were used to link increased Cd exposure with progressive biological effects. Reduction of total soluble protein content in shoots of the Arabidopsis seedlings occurred with increase in Cd concentrations. For the gene expression patterns, seven genes known to be involved in cell division and DNA mismatch repair (MMR) system were investigated by semi-quantitative RT-PCR, and normalized using 18S rRNA gene expression. Expression of the proliferating cell nuclear antigen 2 (atPCNA 2), MutS 3 homolog (atMSH 3) and MutL1 homolog (atMLH1) genes in shoots of Arabidopsis was strongly induced by exposure to 0.75 mg L(-1) Cd, but were repressed by other Cd concentrations whereas exposure to 0.75-6 mg L(-1) of Cd resulted in a decreased expression of atPCNA1, atMSH 2, 6 and 7 genes independently of any observable biological effects, including survival, fresh weight and chlorophyll level of shoots. This work demonstrated that specific gene expression changes could serve as useful molecular biomarkers indicative of Cd exposure and related biological effects.     

氧化镁基催化剂及脱硝性能研究

为控制燃烧烟气中NOx的污染,对共混合方法制备的氧化镁基催化剂进行烟气直接催化分解法脱硝实验研究,分析模拟烟气脱硝塔内温度及床层高度及氧气浓度、NO浓度和空速对脱硝效率的影响.研究表明:氧化镁基催化剂可以采用直接催化分解法对烟气脱硝,脱硝率85%～95%,氧化镁基催化吸附剂组成为氧化镁、固化剂、添加剂;脱硝的床层高度4～5 cm,脱硝反应温度130～170℃,烟气空速2 500～3 000 h-1;研究推测出氧化镁基催化剂存在活性缺陷,并对脱硝机理进行了初步分析.     

不同条件下高炉渣吸附水中无机磷的研究

高炉渣(BFS)是在冶炼生铁过程中产生的固体废弃物,开展高炉渣的资源化研究具有重要意义.为了对水淬高炉渣净化含磷污水的应用提供理论依据,采取等温吸附的实验方法,比较了不同水淬炉渣的吸附磷效果,研究了不同pH和不同温度下水淬炉渣吸附磷的特点,结果如下:利用Langmuir等温吸附方程炉渣吸附磷的过程进行拟合,其相关系数均能达到显著水平.炉渣的碱度越高,吸附磷的效果越好;炉渣对磷的吸附能力随溶液pH的增加而降低,且初始为酸性(pH=2、4)的溶液在吸附达到平衡后pH有所上升,而初始为碱性的溶液(pH=10、12)在吸附达到平衡后pH有所下降;炉渣对磷的吸附是一个自发放热过程.     

QUAL2K模型在西苕溪干流梅溪段水质模拟中的应用

QUAL2K是一维稳态水质模型,由美国环保局开发并在QUAL2E模型的基础上发展起来的.采用QUAL2K模型对西苕溪干流梅溪段的水质进行了模拟和预测.针对西苕溪的具体情况,选用COD、氨氮和总磷作为模拟预测指标,用模型率定法并参考相关文献确定了COD降解系数Kc、氨氮降解系数Kn和总磷平衡系数Kp等水质参数,并对模拟结果进行了验证,结果表明预测值和实测值的相关性较好.     

类芦对铅的耐性及富集能力探讨

通过野外调查和盆栽试验,研究了类芦(Neyraudia reynaudiana)对Pb的耐性和富集能力.研究结果表明,类芦对Pb耐受的临界浓度为800 mg/kg,在此浓度以下Pb对类芦的生长基本无抑制作用.随着处理浓度的增加,类芦生长变缓慢、出现中毒症状,但仍能存活.从富集能力来看,土壤Pb为中低浓度时,类芦的富集能力较强,但Pb浓度超过1 000 mg/kg后地上部富集量增加缓慢,而根部的含量则降低.在各种Pb处理浓度下,类芦地上部Pb含量均大于根部,说明这种植物对Pb有较好的迁移能力.研究发现,类芦具有较高的生物量,因此其地上部Pb迁移总量较高,在土壤Pb浓度为800 mg/kg时类芦地上部的迁移总量可达到221.77 mg/m2.综合分析可知,类芦对中度Pb污染土壤的植物修复具有较大的潜力.     

应用陶粒过滤-陶瓷膜组合对止咳糖浆制药废水深度处理的试验研究

止咳精浆制药废水经生物接触氧化一体化废水处理装置处理后,其出水中COD、BOD和氨氮等主要污染物质均不能达标排放.在实验室中采用陶粒过滤-陶瓷膜组合对经一体化处理装置处理后的制药废水进行深度处理,在陶粒柱反应器选用粒径为1～2 mm的陶粒滤料,陶瓷膜反应器选用孔径为2～3/μm陶瓷膜的条件下对水样进行测试.废水经陶粒过滤-陶瓷膜组合处理后,其BOD、COD、SS和氨氮指标均可稳定达标排放.     

污泥龄对LSP & PNR污泥减量新工艺运行效能的影响

通过研究分析污泥龄(SRT)对富磷污水除磷的LSP&PNR污泥减量新工艺运行效果的影响,结果发现,延长污泥龄有利于提高系统的厌氧释磷能力,但不影响其总的除磷率,同时磷的回收比例增大,当SRT=50 d时,磷回收率取得最大值70.4%;LSP&PNR系统污泥龄增加,还有利于污泥产率的降低.试验还发现,排富磷污水除磷的长污泥龄LSP&PNR系统的除磷效率与污泥产率之间不存在制约关系,即系统可以同时获得优异的污泥减量与生物除磷效果,当SRT=50 d时,每降解1 kg COD仅产生0.143 kg污泥,而除磷率达最高值92.8%;LSP&PNR系统中SRT、DO与SVI之间存在一定的相关性,在供氧充足(DO=0.8～1.5 mg/L)条件下,SRT增加,SVI越高,但对于SRT为50 d的LSP&PNR系统,稳定运行时没有污泥膨胀之虞.     

溶胶凝胶法制备磷钨酸掺杂TiO2薄膜及其光催化性能

以钛酸四丁酯为前驱物,采用溶胶凝胶法制备了磷钨酸掺杂的二氧化钛薄膜.通过XRD、FT-TR对该薄膜进行了表征,研究了薄膜在对氯苯酚光降解中的催化活性.结果表明,当磷钨酸与二氧化钛摩尔比为0.01:1、薄膜烧结温度600℃、对氯苯酚溶液浓度30 mg/L(pH＝5)、光催化8 h的条件下,对氯苯酚的降解率超过90%,且薄膜可以重复使用.磷钨酸对二氧化钛的光催化活性具有明显的促进作用.