磁性吸附材料CuFe2O4吸附砷的性能

根据Cu(Ⅱ)和Fe(Ⅲ)都对砷有较强的亲和性,制备了同时含有Cu(Ⅱ)和Fe(Ⅲ)的、可用磁分离方法进行分离回收的磁性吸附材料CuFe₂O₄,并对其进行了表征及吸附砷的性能研究.结果表明,该吸附剂对砷的吸附能力与溶液pH有关,在弱酸性及中性条件下,吸附砷的能力最强,而对As(V)的吸附能力比对As(Ⅲ)更强些,在平衡浓度为10μg/L时,其吸附容量可达10mg/g左右,可以很容易地将水中浓度为1～20mg/L的As(V)降到10μg/L以下.实验考察了几种无机阴离子对吸附砷的影响,表明较高浓度(砷浓度的20倍)的硫酸盐对As(Ⅲ)和As(V)的吸附均有一定影响,盐酸盐及磷酸盐则影响不明显;负载的As(V)可较容易地用0.1mol/L NaOH洗脱下来,使吸附剂再生,而As(Ⅲ)则难以洗脱,这与2种价态砷的吸附机理不同有关.     

就业与税收关系

目前，我国的劳动就业形式依然严峻。如何破解这个难题，已经成为我国能否顺利推进改革进程的一个关键性问题。我们应该注意到，劳动就业问题的产生是社会经济生活中众多相关因素共同影响的结果。因此，在我们探讨劳动就业问题的时候，必须找到影响劳动就业问题的相关因素并着力研究它们之间的联系，以综合的，全局的目光对就业问题加以审视，才能真正把握我国劳动就业问题的实质，才能使解决劳动就业问题的措施取得预期的效果，才能使劳动就业问题的解决走出简单应对的“陷阱”。     

中国环保事业的回顾与展望

1970年至现在的30年,中国的环境保护事业大致经历了三个阶段:1970年至1978年,是中国环境保护的萌芽和起步阶段;1979年至1991年,是中国环境保护的奠基和成长阶段;1992年至现在,是中国环境保护的发展和壮大阶段。本文对中国环保事业的发展历程进行了回顾和论述,在此基础上,展望了环境保护的前景,抒发了梦想与期待。     

天然浑浊水中共存无机阳离子的电动化学特征

引入流动电流这一重要电动化学参量，研究了在天然浑浊水中ＳＣ的基本模式，撮了ＳＣ与水中悬浮胶体颗凿表面电荷量及无机阳离子之间的理论关系，探讨了离子的浓度，性质，存在环境等对体系电动特性的影响，并对水中常见８种阳离子共存条件下的电动化学特性进行了实验分析，从而建立了无机阳离子对胶体的聚沉能力与电动响应特性之间的实际联系。     

Quantitative and qualitative characteristics of dissolved organic matter from eight dominant aquatic macrophytes in Lake Dianchi, China

The aim of this research was to determine and compare the quantitative and qualitative characteristics of dissolved organic matters (DOM) from eight aquatic macrophytes in a eutrophic lake. C, H, N, and P in ground dry leaves and C, N, and P in DOM of the species were determined, and C/N, C/P, C/H, DOC/C, TDN/N, TDP/P, DOC/TDN, and DOC/TDP were calculated. Chemical structures of the DOM were characterized by the use of multiple techniques including UV-visible, FT-IR, and ¹³C CP/MAS spectra. The results showed subtle differences in quantity and quality of DOM among species and life-forms. Except oriental pepper which had a C/H of 0.7, C/H of all the other species was 0.6. C/N and C/P of ground leaves was 10.5–17.3 and 79.4–225.3, respectively, which were greater in floating and submerged species than in the others. Parrot feather also had a small C/P (102.8). DOC/C, TDN/N, and TDP/P were 7.6–16.8, 5.5–22.6, and 22.9–45.6 %, respectively. Except C/N in emergent and riparian species, C/N in the other species and C/P in all the species were lower in their DOM than in the ground leaves. DOM of the macrophytes had a SUVA₂₅₄ value of 0.83–1.80. The FT-IR and ¹³C NMR spectra indicated that the DOM mainly contained polysaccharides and/or amino acids/proteins. Percent of carbohydrates in the DOM was 37.3–66.5 % and was highest in parrot feather (66.5 %) and crofton weed (61.5 %). DOM of water hyacinth, water lettuce, and sago pondweed may have the greatest content of proteins. Aromaticity of the DOM was from 6.9 % in water lettuce to 17.8 % in oriental pepper. DOM of the macrophytes was also different in polarity and percent of Ar–OH. Distinguished characteristics in quantity and quality of the macrophyte-derived DOM may induce unique environmental consequences in the lake systems.     

文明的衰败与启迪

人类历史上产生了古代埃及、古代两河流域、古代印度、古代希腊、古代印加、古代中国等光辉灿烂的文明,但都出现了由于人为因素引起的生态破坏带来的文明衰败的现象,留下深刻的经验教训和启迪。人类必须尊重自然、善待自然、也必须师法自然、遵循自然规律,还必须保护环境、保护自然、维护生态环境的平衡与和谐,只有如此人类文明将会走向光辉的彼岸。     

经济发展与环境保护双重目标下的中国能源战略

能源作为国民经济的基础,在中国经济发展过程中一直受到很大重视。进入80年代以后,随着能源生产和利用中引起的环境问题逐步得到重视,环境保护目标开始成为制定能源发展战略和发展规划的一个重要考虑因素,这种格局在中国未来能源战略中将继续存在。     

浅谈危险化学品从业单位安全标准化

近一段时间以来,危险化学品事故频发,造成了严重的社会影响.胡锦涛总书记和党中央、国务院领导对此高度关注,并分别做出重要批示,要求深刻分析事故多发的原因,切实加强危险化学品综合治理和事故防范工作.为切实落实国家的相关法律和规定,强化企业安全生产主体责任,建立安全生产长效机制,提高企业本质安全水平,国家安监总局下发了<关于开展安全质量标准化活动的指导意见>,要求在全国范围内广泛开展安全质量标准化活动.     

高铁酸盐对藻类肝毒素的降解

研究高铁酸盐对悦目颤藻(Oscillatoria amoena)肝毒素(Microcystin-LR)的降解效能及其与pH的关系. 结果表明,处理有机质含量很高的藻类肝毒素粗提液,当高铁投加量增到40mg/L,pH控制在6～10,肝毒素几乎被完全降解.同时高铁的还原产物Fe³⁺、Fe(OH)₃发挥其助凝、絮凝的作用,对水体中有机质吸附沉降去除,TOC去除率达到50%左右,铁几乎无残留.高效液相色谱分析发现,作用机制可能是高铁氧化或异构化Adda基团的共轭双键,使Adda基团的结构发生变化,从而降低其毒性.     

Phytoplankton photosynthetic adaptation to high frequency light fluctuations simulating those induced by sea surface waves

In order to test the ability of phytoplankton to adapt to the high frequency light fluctuations induced by sea surface waves, the green alga Dunaliella tertiolecta was grown under both steady and fluctuating (0.1, 1.0 and 10 Hz) illuminations. The latter conditions reproduced those fluctuations experienced by phytoplankton in the upper photic layer. For each culture, photosynthesis versus irradiance were measured under four incubation frequencies (steady, 0.1, 1.0 and 10 Hz fluctuating illuminations). Results indicated that growth rates were similar for algae grown under steady light and 10 Hz fluctuating light (0.26–0.33 d^–1). Cells grown at 0.1 and 1.0 Hz showed lower growth rates (0.17–0.26 d^–1). Chlorophyll a and b were significantly higher under 0.1 and 10 Hz frequencies than under steady illumination; at 1.0 Hz, there were no significant differences with steady light. No changes in carotenoids were evidenced at any frequency tested. Photosynthetic measurements showed that algae grown under steady illumination had higher photosynthetic efficiency and capacity when incubated under steady and 0.1 Hz fluctuating light. Photosynthetic characteristics of algae grown under 0.1 Hz illumination did not show any clear responses to fluctuating light. Algae grown under 1.0 or 10 Hz had higher photosynthetic efficiency and capacity than those grown under steady illumination, when incubated under 1.0 and 10 Hz light. This suggests that microalgae grown under high frequency illumination (1.0 and 10 Hz) can adapt their photosynthetic characteristics to the rapidly fluctuating light regime experienced during growth, and that algae grown under steady conditions respond better to steady or slowly fluctuating (0.1 Hz) light. Such an adaptation provides a means of probing the photosynthetic responses of phytoplankton to vertical mixing.Contribution to the program of GIROQ (Groupe interuniversitaire de recherches océanographiques du Québec)