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371.
锌铜复合氧化物光催化降解甲基对硫磷   总被引:3,自引:0,他引:3  
采用共沉淀法制了锌铅复合氧化物光催化剂,并通过其光催化降解甲基对硫磷农药。结果发现,锌铜复合氧化物能有效地利用空气中的氧,使甲基对硫磷快速光降解,其中ZnO是一个较好的氧化物半导体。  相似文献   
372.
污水零排放可以最大限度地减少工业废水对环境的污染,减少水资源的浪费。企业通过环境论证和风险分析,不断完善工业废水的排水控制和污染物治理措施,制定科学实用的应急预案,实现废水零排放,从而使水资源充分得到利用,环境安全更可靠。  相似文献   
373.
Summary. HPLC analysis of secondary metabolites represents an efficient tool for the studying of plant chemical diversity under different aspects: chemotaxonomy, metabolomics, adaptative responses to ecological factors, etc. Statistical analyses of HPLC databases, e.g. correlation analysis between HPLC peaks, can reliably provide information on the similarity/dissimilarity degrees between the chemical compounds. The similarities, corresponding to positive correlations, can be interpreted in terms of analogies between chemical structures, synchronic metabolisms or co-evolution of two compounds under certain environment conditions, etc. . In terms of metabolism, positive correlations can translate precursor-product relationships between compounds; negative correlations can be indicative of competitive processes between two compounds for a common precursor(s), enzyme(s) or substrate(s). Furthermore, the correlation analysis under a metabolic aspect can help to understand the biochemical origins of an observed polymorphism in a plant species. With the aim of showing this, we present a new approach based on a simplex mixture design, Scheffé matrix, which provides a correlation network making it possible to graphically visualise and to numerically model the metabolic trends between HPLC peaks. The principle of the approach consisted in mixing individual HPLC profiles representative of different phenotypes, then from a complete mixture set, a series of average profiles were calculated to provide a new database with a small variability. Several iterations of the mixture design provided a smoothed final database from which the relationships between the secondary metabolites were graphically and numerically analysed. These relationships were scale-dependent, namely either deterministic or systematic: the first consisted of a monotonic global trend covering the whole variation field of each metabolites’ pair; the second consisted of repetitive monotonic variations which gradually attenuated or intensified along a global trend. This new metabolomic approach was illustrated from 404 individual plants of Astragalus caprinus (Leguminoseae), belonging to four chemical phenotypes (chemotypes) on the basis of flavonoids analysed in their leaves. After smoothing, the relationships between flavonoids were numerically fitted using linear or polynomial models; therefore the co-response coefficients were easily interpreted in terms of metabolic affinities or competitions between flavonoids which would be responsible of the observed chemical polymorphism (the four chemotypes). The statistical validation of the approach was carried out by comparing Pearson correlations to Spearman correlations calculated from the smoothed and the crude HPLC database, respectively. Moreover, the signs of the smoothed relationships were finely supported by analogies and differences between the chemical structures of flavonoids, leading to fluent interpretation in relation to the pathway architecture.  相似文献   
374.
李心宏 《上海环境科学》1992,11(4):22-25,33
阐述了在土地处理制革废水过程中污染物的去除机理。其主要方式是物理、化学和生物的去除,并给出在一定土壤状况下去除机理的综合模型。  相似文献   
375.
磷钨酸光催化降解染料废水研究   总被引:24,自引:0,他引:24  
朱秀华  王炜等 《上海环境科学》2001,20(9):444-445,450
以253.7m紫外灯和太阳光为光源,研究了磷钨酸对几种模拟染料废水的光催化脱色性能,实验结果表明,深溶初始pH值及调节溶液pH值所用酸的类型对磷钨酸光催化活性有影响;催化剂投加量及溶液初始浓度是影响溶液脱色率的重要因素,当溶液中磷钨酸的浓度为0.03g/L,初始pH值为2,初始浓度为10mg/L的甲基橙,甲基红、酸性大红及墨水蓝溶液,阳光辐照3h,除墨水蓝外,其它各溶液脱色率均可达到90%以上。  相似文献   
376.
半导体光催化降解分散染料溶液的研究   总被引:26,自引:0,他引:26  
以TiO2半导体为光催化剂对溶液中的分散染料的降解进行了研究,在通空气的条件下,光照50分钟可使50mg/L的染料溶液完全色,COD.r作文经可达70%以上。研究中探讨了通空气、溶液的PH值,光距TiO2重复使用等因素对光催化降解的影响。  相似文献   
377.
环境微生物降解有机磷农药研究进展   总被引:33,自引:0,他引:33  
微生物降解是有机磷农药在环境中去毒降解的主要方式,该文从环境微生物筛选、降解基因的识别、降解酶的种类及其特性、微生物降解底物特异性及微生物降解效果的评价等5个方面,综述了近年来有机磷农药微生物降解方面的研究进展,展望了微生物降解有机磷农药的研究方向。  相似文献   
378.
白腐真菌对染料的脱色与降解   总被引:4,自引:0,他引:4  
利用白腐真菌对染料脱色和降解的过程机理及影响因素进行了较为系统的介绍,结果认为,白腐真菌对染料的脱色及降解作用可能主要是由于其在次生代谢阶段产生的木质素过氧化酶LIPs和锰过氧化酶MnPs所致。在培养基中加入黎芦醇等能够显著提高LIPs的产生;富氮培养基会抑制LIPs的生成;缓冲液的选择对维持适宜的pH值和菌丝的形态有一定作用,从而影响其脱色效果;富氧环境是一切白腐真菌对染料进行脱色和降解的必要条件;适度的搅拌混合有利于反应时的物质之间传递;一般地,在培养时间达到3d以后白腐真菌才能达到较高的脱色与降解活性。染料分子大小和结构及其基团的位置对脱色及降解效果有明显影响。使用特殊填料来提高处理系统中的生物量以克服真菌生长速度相对较慢,提高处理能力是该技术今后的研究重点。  相似文献   
379.
在超临界水中聚苯乙烯泡沫的降解   总被引:31,自引:0,他引:31  
本文研究了聚苯乙烯泡沫在超临界水中的降解反应。考查了反应时间、温度和添加剂对降解反应的影响.实验结果显示,超临界水能将聚苯乙烯泡沫降解为油状产物。在反应的前30分钟内,分子量降低了约98%;提高温度对反应时间短的或无添加剂的配方有明显的促降解作用;添加剂用量在5%左右时,能得到更大的效率成本比。  相似文献   
380.
Lack of theoretical basis for predicting rate and pathways of recovery   总被引:1,自引:0,他引:1  
An inadequate basis for precisely predicting the outcome of lotic ecosystem recovery, whether due to unaided natural processes or management techniques or both, exists because: (1) the field of ecology has not yet matured as a rigorous predictive science; (2) the precise sequence of events, including climatic occurrences, affecting the recovery process may be unique events and thus rarely or never repeated; and (3) even when attempts are made to control the recolonization process through introduction of species, etc., the interaction of these species may not follow deterministic models. Although this symposium focuses on lotic ecosystems, such systems are influenced strongly by exports from the surrounding land mass and, under certain circumstances, this may be the overriding influence on the recovery process; therefore, unless the boundary conditions are determined realistically, the recovery process may not follow desirable pathways. Despite the lack of a robust theoretical support base for lotic ecosystem recovery, some remarkable and rapid recoveries have occurred to either a close approximation of the original condition or to a condition ecologically superior to the damaged condition. In some cases, the recovery was due entirely to natural processes and, in others, often followed relatively straightforward management practices. There is evidence indicating that lotic ecosystem restoration is both cost effective and likely to produce satisfying results relatively rapidly. It is both fortunate that this is the case, since society is likely to support such efforts when the results have been extraordinarily successful, and unfortunate since restoration ecology needs a predictive capability.  相似文献   
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