不同来源溶解态腐殖酸与Cu2+作用的荧光特性

利用三维荧光等高线图以及其所确定的荧光峰荧光强度随溶液化学条件的变化,研究不同来源溶解态腐殖酸与Cu²⁺作用的荧光特性。研究结果表明：溶解态天然腐殖酸中主要存在二类发射荧光的有机物官能团能与Cu²⁺发生络合作用。位于激发波长和发射波长分别为271～281 nm和335～351 nm的荧光峰1所代表的有机物官能团是与Cu²⁺发生络合配位的主要点位;pH值为4～6时,其络合受pH值影响较显著;而受溶液离子强度影响较小。位于激发波长和发射波长分别为223～246 nm和335～371 nm的荧光峰2所代表的有机物官能团与Cu²⁺的络合作用受溶液pH值影响较小,受溶液离子强度影响较显著。溶解态商品腐殖酸荧光峰1′所代表的有机物官能团与Cu²⁺的络合作用荧光特性,与天然腐殖酸荧光峰1所代表的有机物官能团和Cu²⁺络合作用荧光特性相似,在pH值为3～7时,其络合受pH值影响较显著。     

Effects of fulvic acid concentration and origin on photodegradation of polycyclic aromatic hydrocarbons in aqueous solution: Importance of active oxygen

With an Xe arc lamp house as simulated sunlight, the influences of fulvic acid (FA) concentration and origins on photodegradation of acenaphthene, fluorine, phenanthrene, fluoranthene and pyrene in aqueous solution have been studied. Similar effects of FAs, collected from five places around China, on polycyclic aromatic hydrocarbon (PAH) photodegradation have been observed. Active oxygen was of significance in PAH photodegradation with the presence of FAs. For systems with 1.25 mg L⁻¹ FAs, the contributions of OH to PAH photodegradation rates were from 33% to 69%. FAs had two opposite effects, i.e., stimulating the generation of active oxygen and advancing PAH photodegradation; competing with PAHs for energy and photons and restraining PAH photodegradation. Generally, photodegradation rates of the 5 PAHs decreased with the increase of FAs concentration; except fluoranthene and pyrene were advanced in solutions with low FA concentration. The influences of FA concentration on PAH photodegradation were more significant than FA origin.     

纳米SiO2对微污染物HA、SDS及NH3-N的助凝特性研究

以聚合氯化铝PAC为混凝剂,纳米SiO₂为助凝剂,对含有下列微污染物：十二烷基硫酸钠（SDS）、氨氮（NH₃-N）或腐植酸（HA）的高岭土悬浊液进行混凝沉降实验。借助形态学理论、电镜观察与图像分析技术,研究纳米SiO₂对微污染物的助凝作用效果、吸附特性与絮体结构的形态学特征。结果表明：（1）在含有HA、SDS、NH₃-N的模拟原水中,污染物去除率与浊度去除率的相关性随污染物分子量的增大而增强;（2）纳米SiO     

Fenton及电-Fenton处理难降解有机废水技术

Fenton法与电-Fenton法属于高级氧化技术(Advanced Oxidation Technologjes,AOTs),是由H2O2与催化剂Fe2 所构成的氧化体系.在Fenton体系中,H2O2在Fe2 的催化剂作用下,能产生两种活泼的氢氧自由基(HO2·和·OH),从而引发和传播自由基链反应,加快有机物和还原性物质的氧化.本文简要介绍了Fenton法与电-Fenton反应的机理和应用在催化氧化难降解废水领域中的处理技术及研究进展.     

Humic substances

GOALS, SCOPE AND BACKGROUND: Changing environmental conditions and handling stress are well known to cause chronic or acute stress situations in fish with subsequent infections. These requires a therapy by means of antibiotics and chemicals. In contrast to the huge number of pathogens, only a few substances are permitted for application as therapeutics in German aquaculture. Hence, there emerges an urgent need for highly effective and residueless alternatives. MAIN FEATURES: The prophylactic stimulation and training of the defense system of fish by alternative approaches becomes increasingly necessary. One approach is the application of dissolved humic substances (HS) of natural or artificial origin. For example, there exist several reports on the positive effect of HS to fishes. These effects shall be considered in detail. Furthermore, the impact of HS on the constitution of parasites and pathogens will be displayed. The reports on this issue are diverse, if not inconsistent. We try to shed some light on these discrepancies. The last aspect covered by this review is the outdated paradigm that calcium ions act as antidotes. In the presence of HS, even the opposite effect may occur. APPROACH: To overcome old paradigms on HS and their potential interactions with fish and fish parasites, we reviewed recent international literature, as well as 'grey' literature. We also include results from own former and ongoing studies. RESULTS AND DISCUSSION: HS are able to increase the physiological condition of the individuals and to reduce adverse physiological and histological consequences caused by stress; the mechanism behind remains obscure. HS detoxify heavy metals and organic pollutants. Damages caused by several fish pathogens, such as bacteria and parasites, can be repaired more quickly in the presence of HS. Some parasites--mainly fungi--appear to be directly affected by HS. Comparing the fungicidal effects of HS from various sources, evidence is increasing that the aliphatic moiety may be the effective structures. However, further research is necessary to relate more physiological and anti-pathogenic effects to the chemical characteristics of HS. CONCLUSIONS: HS are not real alternatives to strong traditional therapeutics. However, they show different advantages in repairing secondary, stress induced damages in fish. The ecophysiological relevance of HS in either aquatic systems or aquaculture is getting conspicuously. PERSPECTIVES: The lack of therapeutic and antiparasitic substances in aquaculture requires new strategies and ways of thinking. The search for alternatives to the 'traditional' chemical therapeutics calls for the intensive research. Inevitably, this search will lead to an intensive contemplation on HS as 'health promoting substances' and/or even therapeutics. Basic research is needed to detect the functional groups of the HS responsible for the effects observed. Health promoting effects of first investigations made in vitro to affect pathogens via application of HS and several field studies with HS raises hopes for a broader utilisation of HS to reduce stress consequences in fish and fish pathogens residuelessly.     

Humic Acids from Endemic Arsenicosis Areas in Inner Mongolia and from the Blackfoot-Disease Areas in Taiwan: A Comparative Study

The physical and chemical properties of humic acids (HA) extracted from drinking waters from the endemic arsenicosis areas in Inner Mongolia and from the Blackfoot disease (BD) areas in Taiwan are studied by using AAS (atomic absorption spectrophotometry), ICP-MS (inductively coupled plasma emission-mass spectrometry), IR (Infrared spectroscopy), FR (fluorescence spectrometry) and TLS (total luminescence spectroscopy) in order to shed light on the pathogenesis of BD with the concern as to whether the disease may eventually occur in arsenicosis-affected areas in the Mainland of China. Ames test and lipid peroxidation experiments were also conducted on these HA samples. It is found that water samples from the two regions are high in arsenic (As) with strong fluorescence and apparent positive correlations between As content, fluorescence, pH and total dissolved solids (TDS). The water samples are similar in fluorescence spectra but differ somewhat in IR and TLS between the two regions. The difference may be a reflection of the difference in radicals and structure of the HA owing to different hydrogeological conditions, and may also be related to the difference in their biological effects, i.e., HA from Inner Mongolia have a stronger ability to cause lipid peroxidation while HA from Taiwan exhibits a more prominent effect of mutation with respect to TA98(±S9).     

甲磺隆在土壤腐殖物质中结合残留的动态变化

土壤中14 C 甲磺隆的可提取态残留物随时间延长不断降低 ,而其结合态残留率第 2 8天达最高 .14 C 甲磺隆结合态残留物在土壤腐殖物质中的分布是 :富啡酸 胡敏素 >胡敏酸 .在处理最初 2 8天 ,富啡酸中14 C 甲磺隆结合态残留物不断增大 ,随后减少 ;胡敏素中的结合态残留量在 2 8— 2 2 4天变化不大 .14 C残留物在不同土壤之间的结合及其分布都是有差异的 ,与土壤pH值、粘粒矿物类型等都有密切关系