微型舱模拟室内环境中活性炭净化甲醛的能力

利用微型实验舱(0.04 m3)模拟室内甲醛环境进行活性炭吸附实验,研究吸附后甲醛浓度随时间的变化趋势,计算活性炭对甲醛的净化效率、吸附速率和饱和吸附量,探索活性炭对室内甲醛的吸附规律.研究发现,当甲醛含量为0 ～0.40 mg,活性炭用量为0.5g时,舱内甲醛浓度随时间延长呈指数递减变化趋势,吸附后0～0.5 h甲醛浓度递减得最快,0.5～2h递减速度变缓,2～4h甲醛浓度基本上保持不变;研究E0A1、E1A4曲线斜率K及活性炭甲醛净化效率发现,每次吸附过程活性炭吸附2h可达到吸附平衡,活性炭进行3次吸附平衡即可达到吸附饱和,每次实验第一次吸附过程、每次吸附过程前半小时活性炭对甲醛的吸附能力最强;活性炭的吸附速率在吸附初期迅速降低,最后趋近于0;等量椰壳活性炭在一定浓度的污染物环境中饱和吸附量是个定值.说明使用活性炭净化室内甲醛有一定的规律可循.     

The Vegetation Coverage Dynamic Coupling with Climatic Factors in Northeast China Transect

Based on SPOT-VGT images and meteorological data, this paper applied an integrated method to investigate the vegetation dynamic and its response to climate factors during 1998-2008 in Northeast China Transect, one of 15 ecological transects listed in the International Geosphere-Biosphere Programme. The main findings are as follows: (1) The NDVI time series presented nonlinear patterns that vary with timescales. The series fluctuated greatly at the smallest timescale (20?days), showing no salient trend, whereas a trend manifested itself more and more with the increase of time scale and finally stabilized at the 320-day scale. Little difference was found between vegetation types about the NDVI periodicity, as they occurred on either a 280-day or a 290-day cycle. (2) NDVI exhibited a significant correlation with temperature, precipitation, and sunshine hours. Overall, the correlation between NDVI and temperature was the highest, followed by precipitation, sunshine hours, and relative humidity. For different vegetation types, the correlations between NDVI and climate variables diversified, increasing from desert steppe to typical steppe, meadow steppe, and forest. (3) The periodicity of temperature and precipitation occurred in either a 280-day or 290-day cycle, which was approximately coincident with that of NDVI. This further supported the significant relationship between NDVI and these two climate factors. (4) At all the time scales under examination, NDVI and temperature and precipitation are significantly, positively correlated, especially at the 160-day scale, which can be regarded as the most suitable time scale for investigating the responses of vegetation dynamics to climate factors at most stations.     

光催化与生物技术联用工艺处理油漆废气中试研究

光催化与生物技术联用工艺用于油漆生产、加工过程有机废气的现场处理,中试实验结果表明:油漆生产、加工过程现场的主要污染物是甲苯、乙苯、间/对二甲苯和邻二甲苯等苯系物,浓度在27～55 mg/m3之间。单独使用光催化和微生物技术现场处理这些苯系物,其去除效率都不很高。虽然在中试开始阶段光催化对苯系物的平均去除效率达到了86.2%,在中试稳定期,光催化技术对苯系物的平均去除效率却只有67.6%,而生物滴滤床在成功挂膜之后对现场有机废气的平均去除效率也仅为67.5%。但是将这两种工艺联合使用之后,在中试稳定期该组合工艺对苯系物的平均去除效率可以达到99.2%。     

氧化亚铁硫杆菌浸铜研究及胞外多聚物的作用

为了获得氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f)以及胞外多聚物(extracellular polymeric sub-stances,EPS)对铜浸出的作用结果,进行了透析袋实验,设置2个处理,2者的浸出液均为成熟菌液,但一个将铜片装入透析袋中以隔离A.f及EPS与铜的直接接触。结果表明:(1)菌液的处理和加透析袋的处理中铜都得到了浸出,240 h铜的浸出浓度分别为6 796 mg/L和1 366 mg/L,可知A.f及EPS与铜片直接接触能促进铜的浸出;(2)透析袋的处理中Fe3+保持较高浓度,说明Fe3+与EPS络合后被阻挡在透析袋外面从而不能与铜反应,可知EPS在A.f浸铜中起了媒介载体的作用;(3)2者的SEM图表明无透析袋的处理A.f与铜在实验初期发生了吸附,实验后期则无,实验初期铜快速浸出是由于传质距离短,而后期速度变缓是由于传质距离增大。     

不透水表面雨水径流污染物冲刷规律研究

针对雨水径流污染冲刷模型中降雨强度与污染物冲刷存在的时间差问题,采用有效降雨强度替代降雨强度,建立了径流污染物冲刷模型,并利用建立的模型对不透水表面雨水径流污染物冲刷进行了模拟。结果表明,模型对SS、COD、TN和TP模拟的相关系数R2平均为0.87、0.81、0.93和0.89,具有较高的模拟精度。SS、COD、TN和TP的冲刷系数分别为0.77、0.66、0.92和0.74 mm-1,TN的冲刷系数略高,但总体相差不大。SS、COD、TN和TP均显示了较强的初期冲刷效应,在有效降雨强度为4 mm时,截留初期雨水径流量的35%~40%,即可控制70%以上雨水径流污染物。建立的模型可应用于研究不透水表面的雨水径流污染物冲刷规律,为雨水径流污染物控制提供理论计算依据。     

高浓度铬污染土壤水浸泡与电动修复联合处理实验

对含铬量为2 142 mg/kg的铬污染土壤首先使用蒸馏水进行6轮浸泡试验,然后再进行电动修试验。土壤经过浸泡、通电24 h和72 h处理后总铬的去除率分别为:47%、61%和70%,表明预浸泡可以显著降低电动修复的负荷从而降低整个土壤修复费用。电动修复过程中对土壤两端的温度进行了测量以间接反映土壤电阻的分布和变化情况。结果显示土壤电阻逐渐上升,从阴极端开始逐渐过渡到阳极端,60 h之后达到最高值并保持稳定。电动修复的电流效率随土壤中铬浓度的降低而下降。此外,浸泡和电动修复均导致整个土壤和各断面铬浓度分布不均匀性增大。     

聚丙烯基改性纤维固相萃取水中的苯酚

通过高能电子束辐照的方法,在聚丙烯（PP）纤维基体上分别接枝长链丙烯酸十八酯（SA）和亲水性丙烯酸-β-羟乙酯（HEA）2种单体,并将该纤维作为固相萃取填料,用于固相萃取（SPE）水中的痕量苯酚。研究了SPE过程中上样速度、洗脱溶剂、洗脱体积以及洗脱速度等因素对纤维萃取效果的影响。结果表明,改性纤维对痕量苯酚的富集倍数达95~145倍,回收率达到90%~98%,甲醇对纤维有良好的再生效果,纤维重复使用6次以内时,吸附性能无明显变化。     

Effect of C/N ratios on the performance of earthworm eco-filter for treatment of synthetics domestic sewage

Purpose

The performances of filter systems that use earthworms and plants, combined with earthworm eco-filter (EE) systems in treating synthetic domestic sewage (SDS) with different C/N ratios, were investigated for a 9-month period.

Methods

The effects of the combination of filters, earthworms, plants, as well as the combination of earthworms and plants on SDS nutrient removal efficiency were separately investigated to select the optimum system for treating SDS. The results of the current study could be used to determine how treatment performance responds to different C/N ratios and to explain and predict the performance of an operating EE system.

Results

EE systems with earthworms and plants (EP groups) consistently performed better than the other types of systems (CK, E, and P; that is, without earthworms and without plants, with earthworms and without plants, and without earthworms and with plants, respectively) under all C/N ratios. The highest removal efficiencies of chemical oxygen demand, total nitrogen, total phosphorus, and total organic carbon were achieved under C/N ratios of 6:1, 6:1, 6:1, and 9:1, respectively. The optimum nutrient removal efficiency was achieved at C/N?=?6, and the contribution order for nutrient removal was EP > P > E > CK.

Conclusions

Influent C/N ratios, the time of year, and the synergetic effects of earthworm behavior and microorganisms significantly affected nutrient removal efficiencies. Considering the removal of all nutrients, EE systems with plants and earthworms achieved optimum removal effects in July when the influent C/N ratio was controlled at 6. Appropriate control of carbon and nitrogen source concentrations permitted the achievement of optimal nutrient removal effects.     

Removal of carbon nanotubes from aqueous environment with filter paper

The potential health and environmental hazards of carbon nanotubes (CNTs) have been a concerned issue. However, in contrast to the wide recognition of the toxicity of CNTs, little attention has been paid to the decontamination/remediation of CNT pollution. In this study, we report that CNTs can be removed from aqueous environment. In the presence of Ca²⁺, CNTs aggregate quickly to micron size and then enable easy and effective removal via normal filtration. After filtration, CNT suspension becomes colorless with the remnant CNT concentration less than 0.5 μg mL⁻¹, a safe dose based on the published data. The filtration approach also works well in the presence of typical surfactant and dissolved organic matter. The removal efficiency is Ca²⁺ concentration-dependent and regulated by the initial pH value and ionic strength. Our study is helpful for future decontamination of CNTs from aqueous environment.     

二氧化氯对颤蚓成虫灭活效果及灭活作用机制

采用对苯二甲酸（terephthalic acid,TA）作为羟基自由基（hydroxyl radical,·OH）捕捉剂,利用荧光分光光度法测定了二氧化氯（CIO2）接触后颤蚓体内-OH浓度变化,结合颤蚓灭活率、过氧化氢酶（catalase,CAT）和丙二醛（malondi．alderhyde,MDA）等指标的测试结果,研究了CIO2对颤蚓成虫的灭活效果及灭活机理。结果表明,ClO2对颤蚓成虫灭活效果显著。当C1O2投加浓度超过0．4mg／L,可对颤蚓体内·OH产生明显的诱导效应,并且·OH诱导效应与颤蚓灭活率直接相关。接触条件下CAT变化情况表明,颤蚓受到了明显的氧化胁迫,且对颤蚓体内抗氧化系统有破坏作用,MAD变化结果则表明ClO2对颤蚓的脂质过氧化作用不明显,可以对颤蚓表皮层有效渗透。上述结果证实了CIO2对颤蚓成虫的灭活作用机制之一是诱导其体内生成·OH,产生氧化胁迫,而CIO2对颤蚓抗氧化系统的破坏作用和对颤蚓表皮层的有效渗透进一步增强灭活效果。