碳纳米管负载纳米四氧化三铁多相类芬顿降解亚甲基蓝

在课题组前期研究的基础上,以碳纳米管(MWCNTs)为载体制备了Fe3O4/MWCNTs复合物并作为催化剂,以染料亚甲基蓝(MB)为降解对象,研究了该催化剂催化H2O2对亚甲基蓝溶液的降解特性及其影响因素,并考察了催化剂的重复使用效果,探讨了催化反应的机理.结果表明,在pH值3~8的范围内,催化反应体系都能有效降解MB,最佳pH值为3.5.随着催化剂投量的增加,MB的降解率明显提高,500 mg·L-1催化剂投量条件下,MB的降解率最高.随着H2O2初始浓度的增加,MB的降解率增加,10 mmol·L-1时MB的降解率最高.溶液中共存的阴离子会降低MB的降解率.在最佳条件,即温度25℃、H2O2浓度10 mmol·L-1、催化剂浓度500 mg·L-1的条件下,0.20 mmol·L-1MB在30 min内的降解率达到99.1%.催化剂重复使用后仍然具有较好的催化活性,说明Fe3O4在MWCNTs表面负载比较牢固,催化剂具有反复使用的能力.催化反应机理是催化剂催化H2O2产生羟基自由基,高活性的羟基自由基氧化MB.     

间接竞争ELISA方法测定水中2，4-D的研究

以2,4-D-BSA为包被抗原,采用自行制备的2,4-D单克隆特异性抗体6D11建立了水中2,4-D的间接竞争 ELISA检测方法．本研究比较了包被抗原2,4-D-BSA浓度分别为240ng·mL-1、120ng·mL-1和60ng·mL-1的反应体系和竞争反应时间为60min和15min的间接竞争ELISA剂量-反应曲线,确定了当包被抗原浓度为60 ng·mL-1、竞争反应时间为15min时,剂量-反应曲线的IC50值较低．采用上述实验条件分别测定了由PBS缓冲溶液、饮用水、清华大学地下水和圆明园福海地表水配制的2,4-D标准溶液的剂量．反应曲线,发现实际水样的基质效应对检测结果的影响较大;采用实际水样和PBS缓冲溶液配水在含有5％乙醇的PBS缓冲体系中反应的方法,基本上消除了基质效应对检测结果的干扰．采用上述优化试验条件,测定2,4-D浓度分别为0．5mg·L-1、0．125mg·L-1和0．03mg·L-1的加标样品,测定数据的准确度符合痕量有机污染物定量检测对准确度的要求,但是平行样品测定数据之间的变异系数较大,需要进一步改进检测方法,用于实际水样的检测．     

Perspectives for sustainable management of cedar forests in Lebanon: situation analysis and guidelines

The signature and ratification of the convention on biological diversity by the Lebanese government has boosted the declaration of nature reserves. Cedar forests formed the pilot ecosystems, using international funds, for the implementation of a conservation programme and development of management plans. Although different in their attributes, all recent nature reserves have the same basic management objectives and goals but they ignore the idea of taking into account the difference in specific site features and assets that could boost the success of any management plans. Twelve cedar forests flourish in the Mount Lebanon chain. These forests are either protected by the forestry law or are declared as nature reserves by the Ministry of Environment. The results reveal, through Participatory Rural Appraisals and Rapid Rural Appraisals, that religion, geographical location and land ownership play, to a certain extent, a role in adopting successful management practices of cedar forests. The RRAs and PRAs spell out the origins of woodcraft, old stories memorized by elderly people and ethnobotanical knowledge. The 4Rs tools method adopted highlighted the need for more collaboration and synergy of effort between various institutions. The social, ecological and economic aspects of the regions play a major role in defining the backbone of management plans for cedar forests in Lebanon. The present paper proposes guidelines for the establishment of a network of cedar nature reserves in Lebanon adopting collaborative management and assigning a separate role for each reserve; the details rely on the site’s natural features, as well as socio-economic and cultural characteristics. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue     

软锰矿与氧化亚铁硫杆菌吸收SO2过程中的影响因素

研究了低浓度软锰矿浆与氧化亚铁硫杆菌(Thiobacillus ferrooxidans,简称 T.f)联合吸收SO2过程中软锰矿浆浓度、T.f菌液量、O2体积分数、气体流量以及SO2进口浓度对硫酸根生成的影响.研究表明:在该体系中,生成的硫酸根浓度随着软锰矿浆浓度、T.f菌液量、O2体积分数以及气体流量的增加而增大;随着进口SO2浓度的增加,硫酸根的生成呈现先增加后减少的趋势.     

江津润湿时间的温度分布研究

采用直接读取、4点统计、24点统计三种方法研究了江津试验站1998年的润湿时间的温度分布,研究表明,可以利用全年每天2、8、14、20点的4个数据统计年润湿时间的温度分布;江津地区润湿时间的温度分布特征主要为：(1)99％的年润湿时间是在5℃至30℃温度范围,每月润湿时间的温度波动一般为15℃;(2)在(0～5)℃、(5～10)℃、(10～15)℃、(15～20)℃、(20～25)℃、(25～30)℃、(30～35)℃区间内,4点统计法各区间润湿时间的百分比分别为0.34％、13．4％、24．5％、18．3％、26．0％、17．4％、0．0％。     

Application of recombinant gene technology for production of polyhydroxyalkanoic acids: Biosynthesis of poly(4-hydroxybutyric acid) homopolyester

Screening of a large number of bacteria revealed several strains, which utilize 1,4-butanediol and/or 4-hydroxybutyric acid (4HB) as a carbon source for growth and for synthesis of polyhydroxyalkanoic acids (PHA) containing 4HB as one constituent among others (mostly 3-hydroxybutyric acid). However, none of the wild-type strains investigated in this study was able to produce a homopolyester consisting solely of 4HB. Only several poly(3-hydroxybutyric acid)-leaky mutants ofAlcaligenes eutrophus strain JMP222 synthesized poly(4HB) homopolyester, which amounted to approximately 10% (w/w) of the cellular dry matter. If the PHA synthase structural gene ofA. eutrophus strain H16 was expressed in these mutants, the amount of poly(4HB) was increased to approximately 30% (w/w). The occurrence of poly(4HB) was demonstrated by gas chromatographic as well as¹H and¹³C nuclear magnetic resonance spectroscopic analysis.Paper presented at the Bio/Environmentally Degradable Polymer Society—Second National Meeting, August 19–21, 1993, Chicago, Illinois.     

TOXIC EFFECTS OF PETROLEUM AND SHALE JP-4 AND JP-8 AVIATION FUELS ON FATHEAD MINNOWS1

ABSTRACT: Static 96-hour median lethal concentrations were determined for the water-soluble fraction (WSF) of both petroleum-derived and shale-derived avaiation fuels (JP-4 and JP-8) using fathead minnows. JP-8 was more toxic than JP-4 except for one shale JP-4 sample that was as toxic as the JP-8. Petroleum and shale JP-8 were similar in toxicity. The toxicity of shale JP-4 was less clear. Shale JP-4 from three vendor sources revealed differing toxicity values. One shale JP-4 sample was more toxic and one less toxic than its petroleum analogue, with the third being equally toxic. Toxicity of the fuels may be enhanced by compounds in the WSF that correspond to chemicals containing 10 or more carbon atoms.     

2-(2''''-喹啉偶氮)-4,5-二甲氧基苯酚的合成及其光度法测定水中的钴

合成了新试剂2-(2'-喹啉偶氮)-4,5-二甲氧基苯酚,研究了其与钴(Ⅱ)的显色反应,在pH=5.5的HAc-NaAc缓冲介质中,在十六烷基三甲基溴化铵(CTMAB)存在下,2-(2'-喹啉偶氮)-4,5-二甲氧基苯酚与钴生成2∶1稳定的配合物,该配合物λmax=575 nm,摩尔吸光系数ε为2.443×104 L·mol-1·cm-1.钴含量在0～0.4 mg/L内符合比耳定律.新方法用于水样中微量钴的测定,结果满意.     

常压消化体系--原子吸收分光光度法测定海洋沉积物中Cu、Pb、Zn、Cd、Cr

根据《海洋监测规范第5部分:沉积物分析》(GB 17378．5-1998)的规范方法,比较近海海洋沉积物成份分析标准物质(GBW07314)在HNO3-HCl04-HF常压消化体系中,在不同温度下Cu、Pb、Zn、Cd、Cr的溶出情况。样品消化液经赶酸后,以HCl浸提、过滤、定容,最后直接用原子吸收分光光度计测定。     

The Effects of Three Thermo Electric Power Plants on Yerkesik-Denizova Forests in Mugla Province (Turkey)

Mugla is a city that is located in the southwest part of Turkey. Three thermo-electric power plants called Yatagan (3 × 210 MW) and Yenikoy (2 × 210 MW)and Kemerkoy (Gokova, 3 × 210 MW) havebeen constructed in this region and also have begun operation in 1982 – 1983 – 1984 (three units), in 1988 and in 1995, respectively. The Pinus brutia forests in Yerkesik–Denizova region have been under the common effects of Yenikoy and Yatagan thermo-electric power plants. Therefore, these Pinus brutia forests have startedto dry in groups since 1988. In addition, Kemerkoy thermo-electric power plant, began operation in 1995.Polluting gases arrived in Denizova-Yerkesik throughKoca Stream Valley Forests.Increasing quantities of polluting gases and especially SO₂ have dried the trees in large amounts in this 1650 ha forestland area. YataganThermo-electric power plant has caused drying of Pinus brutia in Bencik Mountain, which was on the south in 1984–1985. The same phenomenon was seen in Denizova-Yerkesik Forest in 1999–2000. It was observed that sulphur content was varying between 4218–6676 ppm at the Pinus brutia needle samples taken in this region on 16 December 2000. Sulphur contents were correlated with the age of needle (1–2 yr old), density of yellow stains on the needles and amount of drying needles. Particularly in 1996–2000 period, the destruction of chlorophyll in needles due to the impacts of SO₂ was also correlated with narrowing of the annual rings from one year to another. The narrowing ratio of yearly rings reached 60–504% for 94–95 yr old, and 375–661% for 58–63 yr old Pinus brutia trees during the 1986–1990, 1991–1995 and 1996–2000 periods.All these results clearly showed that the decrease in the chlorophyll content in needles under the effect of air pollution caused important reduction in the raw timber production and its inputs to the economy. In other words, drying due to increased ecological sensitivity or direct hazard of pollutants emitted by the power plants and cutting of trees have been notably increased in the region. This has created serious economic losses.