二氧化钛光催化技术处理制药废水的实验研究

通过改变二氧化钛浓度、调节pH值、添加H2 O2及铁离子浓度等实验方法,验证了二氧化钛光催化反应处理制药废水的效果。根据测定制药废水中氨氮、COD浓度,计算氨氮、COD的去除率,得出二氧化钛光催化反应的最佳反应条件,为实际应用提供依据。     

Photocatalytic degradation of NOx in a pilot street canyon configuration using TiO2-mortar panels

Titanium dioxide is the most important photocatalysts used for purifying applications. If a TiO₂- containing material is left outdoors as a form of flat panels, it is activated by sunlight to remove harmful NOx gases during the day. The photocatalytic efficiency of a TiO₂-treated mortar for removal of NOx was investigated in the frame of this work. For this purpose a fully equipped monitoring system was designed at a pilot site. This system allows the in situ evaluation of the de-polluting properties of a photocatalytic material by taking into account the climatologic phenomena in street canyons, accurate measurements of pollution level and full registration of meteorological data The pilot site involved three artificial canyon streets, a pollution source, continuous NOx measurements inside the canyons and the source as well as background and meteorological measurements. Significant differences on the NOx concentration level were observed between the TiO₂ treated and the reference canyon. NOx values in TiO₂ canyon were 36.7 to 82.0% lower than the ones observed in the reference one. Data arising from this study could be used to assess the impact of the photocatalytic material on the purification of the urban environment.     

高效液相色谱法分离和测定甲醛和苯酚

本文讨论了高效液相色谱分离和测定甲醛和苯酚的条件,并对酚醛树脂生产废水进行了实际测定,结果令人满意。     

挥发酚实验用水的探讨

本文对挥发酚实验用水进行探索及改进．直接采用蒸馏水代替无酚水为实验用水。应用于质控考核工作中,取得较理想的显著效果。结果表明．精密度、准确度都符合分析要求,并能降低成本,省时、省电、提高工效,可广泛应用于环境监测工作中,具有普遍实用价值。     

Time dependent influx and efflux of phenol by immobilized microbial consortium

Phenol, like many other organic solvents, is toxic to micro-organisms even at low concentrations. However, some micro-organisms can withstand this toxicity to a certain concentration. To observe the uptake mechanism of phenol, bacteria were isolatedfrom a petroleum refinery effluent and identified. Study was carried out to understand the effect of varying sub-lethal concentrations of phenol, on all the isolated individual bacterial cultures. Out of the bacteria isolated, Serratia liquefaciens was found to tolerate phenol concentration up to 1500 mg l^-1. A microbial consortium of the isolated bacteriawas formulated and immobilized. Individual cultures were also immobilized and uptake of phenol by the immobilized micro-organisms was observed in a nutrient-rich and nutrient-stressed medium containing phenol as a sole source of carbon. A time-dependent uptake of phenol was exhibited by the micro-organismsin nutrient-stressed medium, after which a sudden increase in phenol concentration occurred in the extracellular medium, till it reached back to the initial concentration. This was attributedto an active efflux mechanism adopted by the micro-organisms to withstand the toxic shock.     

垃圾渗出液中酚类物质的气相色谱分析

建立了一种用气相色谱法准确、快速测定垃圾渗出液中酚类物质的新方法。外标法定量分析 4 -甲基苯酚及苯酚。采用填装了 80～ 1 0 0目 Chromosorb WAW DCMS的玻璃填充柱 ,担体上涂渍了 2 % OV-1 7,2 .5% QF-1的固定液 ,分离酚类物质效果较好 ,线性范围为 1 0 0～ 1 50 0 mg/ L,相关系数为 0 .9996,方法回收率为 94 .7%。     

固相微萃取-毛细管气相色谱法快速分析水中酚类化合物

固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点.本工作用固相微萃取富集水中酚类化合物,毛细管气相色谱分离分析,整个分析过程只需45min,检出限可达1.0～10.0μg/L,已用于地面水、海水、工厂废水中酚类化合物含量的测定.     

流动注射在线富集分离荧光分光光度计测定垃圾渗出液中的苯酚

建立了用荧光分光光度计作为流动注射分析的检测器 ,用自行研制的流通池测定垃圾渗出液中苯酚的新方法。方法的线性范围为 0 .0 9～ 0 .6mg/ L,检出限为 5 μg/ L。用于垃圾渗出液的测定 ,结果与 4-氨基安替吡啉法无显著性差异 ,回收率在 96%～ 10 3 %之间 ,该法具有选择性好、灵敏度高、重现性好的特点     

Pathways and Kinetics on Photocatalytic Destruction of Aqueous Phenol

In this study, the TiO₂ photocatalytic decomposition process of aqueous phenol was investigated. The intermediate products generated in the elementary reaction steps in the mineralization process were experimentally identified as hydroquinone, catechol and hydroxyhydroquinone. The concentration variations of these intermediate products with time passage were traced by high performance liquid chromatograph. The pathways of the decomposition process were given. Based on Langmuir isothermal theory and Langmuir-Hinshelwood mechanism, the multi-compounds competition kinetic model was established. In this model, the observed time-dependent concentrations of phenol and the intermediate products were simulated.     

氟利昂替代品降解产物——三氟乙酸对水环境的潜在影响

三氟乙酸 (简称 TFA)是氟利昂替代品的主要降解产物之一 ,该物质会造成大气环境的恶化 ,雨水会将其从大气中去除。三氟乙酸化学性质极其稳定 ,在水中全部溶解。在自然条件下 ,三氟乙酸不降解、不光解、不被土壤吸附、不被微生物分解 ,易于在水体中积累 ,特别是在没有流入和流出的水体及季节性湿地中蓄积。全球雨水中的三氟乙酸 2 0 1 0年预计可达到 1 0 0～ 1 60 ng/L,部分地区地表水可达到 1 60 ng/L。     

紫外光度法测定海水石油类质控指标研究

采取问卷调查的形式对76家"近海网"成员单位海水石油类测定情况进行调查,根据调查问卷获得的数据信息,结合实验室数据,采用控制图法确定了紫外光度法测定海水石油类质控指标限值,包括萃取剂透光率、检出限、校准曲线斜率、平行样偏差等。     

金属离子和氧化剂对3,5-二氯酚光化学降解的影响

在实验条件下 ,Fe2 +、KCl O3、KCl O4 、KBr O3、KIO4 对 3 ,5 -二氯酚光化学降解起加速作用 ,且随其浓度增大 ,加速作用也在增强。KIO4 的加速作用比较强。光照时 ,KIO4 +Mn2 +对 3 ,5 -二氯酚光化学降解的加速作用非常显著。无光照时 ,当 KMn O4 浓度增加时 ,3 ,5 -二氯酚被迅速氧化 ;KIO4 +Mn2 + /Fe2 + 能够使 3 ,5 -二氯酚发生化学降解 ,尤其是 KIO4 +Mn2 + 的作用。     

A holistic approach towards assessment of severity of land degradation along the Great Wall in northern Shaanxi Province,China

The farming and grazing interlocked transitional zone along theGreat Wall in northern Shaanxi Province is particularly vulnerable to desertification due to its fragile ecosystem and intensive human activity. Studies reveal that desertification isboth a natural and anthropogenic process. Four desertificationindicators (vegetative cover, proportion of drifting sand area, desertification rate, and population pressure) were used to assess the severity of desertification in a GIS. The first threefactors were derived from multitemporal remote sensing and landinventory data. The last factor was calculated from census data.It was found that the overall severity of land degradation in thestudy area has worsened during the last two decades with severely, highly and moderately degraded land accounting for 84.2% of the total area in 1998. While the area affected by desertification has increased, the rate of desertification has also accelerated from 0.74 to 0.87%. Risk of land degradation in the study area has increased, on an average, by 155% since 1985. Incorporation of both natural and anthropogenic factors inthe analysis provides realistic assessment of risk of desertification.     

Rural poverty driven soil degradation under climate change: the sensitivity of the disposition towards the Sahel Syndrome with respect to climate

Starting from the basic assumption of the syndrome concept that essentially all of the present problematic civilization–nature interactions on the global scale can be subdivided into a limited number of typical patterns, the analysis of the response of these patterns (syndromes) to climate change can make a major contribution to climate impact research, surmounting the difficulties of more common sectoral ceteris paribus impact studies with respect to their systemic integration. In this paper we investigate in particular the influence of climate on the regional proneness or disposition towards one of the most important syndromes with respect to famines and malnutrition, the Sahel Syndrome. It describes the closely interlinked natural and socioeconomic aspects of rural poverty driven degradation of soil and vegetation on marginal sites. Two strategies of global climate impact assessment on a spatial 0.5°×0.5° grid were pursued: (a) As a measure for the climate sensitivity of the regional proneness, the absolute value of the gradient of the disposition with respect to the global field of 3} 12 monthy normals of temperature, irradiation and precipitation is calculated. (b) The disposition was evaluated for two different climate forecasts under doubled atmospheric CO₂ concentration. For both strategies two new quantitative global models were incorporated in a fuzzy-logic-based algorithm for determining the disposition towards the Sahel Syndrome: a neural-net-based model for plant productivity and a waterbalance model which calculates surface runoff considering vertical and lateral fluxes, both driven by the set of 36 monthly climatological normals and designed to allow very fast global numerical evaluation.Calculation (b) shows that the change in disposition towards the Sahel Syndrome crucially depends on the chosen climate forecast, indicating that the disagreement of climate forecasts is propagated to the impact assessment of the investigated socio-economic pattern. On the other hand the regions with a significant increase in disposition in at least one of the climate scenario-based model runs form a subset of the regions which are indicated by the local climate sensitivity study (a) as highly sensitive – illustrating that the gradient measure applied here provides a resonable way to calculate an upper limit or worst case of negative climate impact. This method is particularly valuable in the case of uncertain climate predictions as, e.g., for the change in precipitation patterns.     

紫外分光光度法直接测定水中酚

通过实验证明,用紫外分光光度法测定水中挥发酚,方法简便、精密度和准确度较好,适用于地表水、地下水和废水中挥发酚的测定,结果令人满意。     

萃取光度法测定高浓度挥发酚初步探讨

用氯仿多次萃取高浓度挥发酚,可提高试样中待测组分的萃取率,其测定结果准确度令人满意。     

Spatial scales and probability based sampling in determining levels of benthic community degradation in the Chesapeake Bay

The extent of degradation of benthic communities of the Chesapeake Bay was determined by applying a previously developed benthic index of biotic integrity at three spatial scales. Allocation of sampling was probability-based allowing areal estimates of degradation with known confidence intervals. The three spatial scales were: (1) the tidal Chesapeake Bay; (2) the Elizabeth River watershed; and (3) two small tidal creeks within the Southern Branch of the Elizabeth River that are part of a sediment contaminant remediation effort. The areas covered varied from 10^–1 to 10⁴ km² and all were sampled in 1999. The Chesapeake Bay was divided into ten strata, the Elizabeth River into five strata and each of the two tidal creeks was a single stratum. The determination of the number and size of strata was based upon consideration of both managerially useful units for restoration and limitations of funding. Within each stratum 25 random locations were sampled for benthic community condition. In 1999 the percent of the benthos with poor benthic community condition for the entire Chesapeake Bay was 47% and varied from 20% at the mouth of the Bay to 72% in the Potomac River. The estimated area of benthos with poor benthic community condition for the Elizabeth River was 64% and varied from 52–92%. Both small tidal creeks had estimates of 76% of poor benthic community condition. These kinds of estimates allow environmental managers to better direct restoration efforts and evaluate progress towards restoration. Patterns of benthic community condition at smaller spatial scales may not be correctly inferred from larger spatial scales. Comparisons of patterns in benthic community condition across spatial scales, and between combinations of strata, must be cautiously interpreted.     

水中挥发酚的测量不确定度评定

建立了分光光度法测定水中挥发酚的合成标准不确定度的数学模式,它由质量的标准测量不确定度和体积的标准测量不确定度组成。应用一个实例对这两部分标准不确定度的分量作了详尽的分析和计算,得出测量扩展不确定度结果。     

4-AAP萃取光度法测定挥发酚的几点体会

介绍了在测定挥发酚过程中对试剂的保存，缓冲溶液pH值的控制，各种试剂的加入顺序及萃取时间的确定等问题的几点体会，并有针对性地提出了解决的办法。     

流动注射分析法在挥发酚测定中的不确定因素分析

从基线波动、气泡干扰、相分离膜干扰及试剂和标准的干扰等4个方面,总结了流动注射分析法在挥发酚测定中的不确定因素,并提出了有效的改进建议。