土壤胶体化学家虞宏正的学术思想与科学贡献

虞宏正是我国著名的胶体化学与物理化学家、教育家。他扎根西北,融汇世界思想,形成了颇具价值的学术思想,至今仍是当代科学研究的精髓与主导思想。他毕生致力于胶体化学、热力学研究,建立了新的分支学科,开创了土壤科学研究所,培育了几代化学科学家,为中国化学学科和农业科学的发展做出了重要的贡献。     

土壤腐殖质的分析化学研究进展

对土壤腐殖质的分析化学研究进展作了综述。具体包含如下几个方面的内容；土壤腐殖质的组成和结构的研究，土壤腐殖质的起源和形成的研究，土壤腐殖质与土壤中有机，无机物质的相互作用的研究以及有机物料的分解，转化及其对腐殖质影响的研究，同时，对土壤腐殖质的研究中有待进一步用分析化学方法解决的几个问题进行了探讨。     

Element concentration cadasters in a Swedish biotope

Summary 62 elements were determined in a Swedish and a German peat bog soil. The results are tabulated in Element Concentration Cadasters. An attempt is made to suggest the Swedish peat bog soil as reference standard for inorganic environmental chemistry and to expand this kind of investigations over all vegetation zones of the world.     

硒的土壤化学及其生物有效性

硒是重要的生命元素。高硒和低硒均会引起动物发生各种疾病，硒由土壤进入植物体，通过食物链控制着动物的硒营养状况，因此研究硒的土壤化学及其对生物的有效性对维护人类健康和牲畜生产是十分有意义的，本文拟就土壤中硒的含量、形态、有效性影响因素，硒的保健作用和调节措施等方面作一综述。     

土壤的植物修复与超积累植物研究

被污染土壤的植物修复将是未来更好与更廉价的修复技术,所以近年来对植物修复与超积累植物的研究兴趣日益增加。本文简要介绍了近期的发展趋势。目前研究的重点包括根际土壤微环境中的复杂反应与吸收过程,金属从土壤向植物根以及从植物根向叶的传输过程,金属在超积累植物中的定位与螯合作用等等。这是分析化学与环境科学及植物科学交叉研究的新领域,充满挑战。     

Intrinsic bioremediation of gas condensate hydrocarbons

Condensate liquids have been found to contaminate soil and ground water at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate end point to support a no-intervention decision. Ground water monitoring, soil gas analysis, and analysis of soil cores suggest that bioremediation is occurring at these sites by multiple pathways, including aerobic oxidation, sulfate reduction, and methanogenesis. Results of over two years of monitoring of ground water and soil chemistry at these sites are presented to support this conclusion.

     

我国胶体与界面化学的发展

胶体与界面化学在能源、材料、生物、化学制造和环境科学等领域具有广泛的应用,并渗透到国民经济的各个主要领域中。所涉及到其中的一些重大科学问题,如土壤改良、功能与复合材料、三次采油、人造血浆、药物缓释与定向、润滑和油漆涂料等,与国家安全、能源开发、环境保护和人民生活等方面密切相关,发展胶体与界面化学学科对社会与经济的可持续发展具有重要的意义。本文综述了我国胶体与界面化学学科30年来的研究进展,尤其是近10年所取得的成就,主要包括新型两亲分子有序组合体的设计与构建、界面化学与有序分子膜、胶体与界面化学在微纳米功能材料合成中的应用新进展、胶体与界面化学在生物医药中的研究新进展,以及胶体与界面化学的研究新方法,并对该学科的发展前景与趋势进行了分析。     

硼的土壤化学及其生物有效性的研究进展

综述了近年来有关硼的土壤化学及其生物有效性的研究成果。主要内容涉及土壤对硼的吸附与硼的解吸及其影响因素；土壤硼吸附的主要化学模型及其优缺点；土壤硼生物有效性的影响因素等；并评述了硼的研究现状。     

城市土壤对铅的吸附动力学特征及影响因素

采用批量法对温州景山森林公园5种不同土壤的Ph的吸附动力学行为进行了研究,初步探讨了不同理化性质土壤对重金属吸附的影响。结果表明,在实验条件下,5种土样均在180rain内达到吸附平衡;抛物线扩散方程、双常数速率方程和Elovich方程能很好地描述5种土壤Pb^2＋动力学行为;随着外源Pb^2＋质量浓度的增大,土壤对Pb^2＋的吸附量都相应增大;通过吸附速率与吸附强度与土壤理化性质相关性分析,得出土壤对重金属铅的吸附速率是土壤各理化性质综合作用的结果,而土壤对铅的吸附强度在很大程度上取决于土壤pH。     

Chromatographic determination of herbicide residues in various matrices

The newest results in the use of various extraction techniques and chromatographic methods such as gas-liquid and high-performance liquid chromatography used for the assessment of herbicide residues in various matrices have been compiled and critically evaluated. Practical employments in water and soil research, environmental protection, clinical and food chemistry are presented.     

Fluoride sorption and associated aluminum release in variable charge soils

Fluoride sorption and related aluminum (Al) release are evaluated in two iron-oxide-rich soils as a function of soil depth, composition, and physical-chemical properties and potential mechanisms of fluoride-surface interaction are suggested. Measured Al concentrations at equilibrium fluoride sorption, reflective of the net balance between Al dissolution and sequestration of the released Al by the solid phase, suggest net fluoride-assisted dissolution of Al-bearing amorphous and crystalline soil minerals. Strikingly, soils of similar depth and horizonation from the same soil order but of distinct soil series exhibited markedly different susceptibility to Al loss in the presence of fluoride, possibly a combined result of differences in the mechanism of fluoride sorption, soil mineralogy, reactivity of the surficial Al and Fe, and soil solution chemistry. Fluoride sorption is strongly correlated with soil Al and Fe present as high-surface-area amorphous and crystalline oxide phases. Fluoride complexation to surficial Al and Fe ions via ligand exchange with surficial OH groups and water molecules appears to be the dominant sorption mechanism. At high dissolved fluoride concentrations (>7 mM), other mechanisms of fluoride retention including adsorption of AlF solution complexes, entrapment in the interparticle pore fluid, and precipitation into solution and/or onto the soil surface are also likely.     

Techniques in chemometrical modeling for micro-pollutants assessment

Summary Chemometrics have been described as effective tools for exploring chemical data, and many software packages are now available on micro-computers. This work evaluate their suitability for environmental analytical chemistry. Guidelines for multivariate method selection are proposed. They are based on the type of variables and the goal of the study. Two examples are proposed to illustrate these methods and their efficiency. Firstly it is shown that a global assessment of Rhine basin mercuric pollution in the Alsace region is possible with Multiple Correspondence Factor Analysis. Several goals are simultaneously reached: a mapping of pollution, a detection of pollution changes during the study period and an evaluation of bio-accumulation as a function of fish species. Secondly the modeling of industrial soil pollution by heavy metals is studied by Multiple Linear Regression. It demonstrates that chemometrics provide us with necessary tools for environmental analytical chemistry but also for toxicological studies or ecosystem modeling.     

Lead Adsorption on a Soil: A Polarographic Study

The adsorption of lead by a non‐contaminated loamy sand soil (Guarda, Portugal) was studied by voltammetric titrations using differential pulse polarography for pH values of 6.0, 6.8 and 7.2 and I of 0.5, 0.1 and 0.01 mol L^?1. After lead or soil additions, residual lead in solution was measured in the presence of the soil particles after an equilibration period, thus with minimum sample manipulation. The characteristics of the surface groups were studied by acid base potentiometric titrations. Lead retention by the soil is influenced both by pH and ionic strength of the medium. From the voltammetric data surface constants and total available binding groups have been estimated according to a complex surface model for the different experimental conditions and the results interpreted in terms of the surface characteristics of the soil and the support medium. Surface binding capacities in the range 1 to 70 mmol Pb kg^?1 were found depending on the pH and the ionic strength. The behavior found is in agreement with what is known in soil chemistry thus supporting the conclusion that voltammetric methods are quite appropriate for determining the extent of interaction between metal ions and soils.     

Stereoselective Synthesis and Biological Profile of All Stereoisomers of Lactam Analogues of Strigolactones GR24 and GR18

Strigolactones (SLs) are signaling molecules involved in plant development and governing interactions with soil microorganisms in the rhizosphere as well as the germination of parasitic weeds. Developing their use in Crop Protection is a promising approach to a sustainable agriculture by mitigating biotic and abiotic stresses. Recently, a new class of lactam analogues of SL has emerged, namely strigolactams, displaying outstanding potency to induce the germination of parasitic weed O. cumana as well as enhanced chemical and soil stability. Herein, we describe the stereoselective synthesis of GR24 and GR18 lactams harnessing the chemistry of chiral keteniminium (KI) salts, in particular the unprecedented reactivity of chloro-substituted KI, supported by DFT calculations. We disclose subsequently the biological activity on corn of the 32 stereopure strigolactams prepared, highlighting the crucial influence of stereochemistry and lactam substitution, rationalized by docking analyses. Finally, we performed stability studies in soil, which reveal that stereoisomers display very different half-lives, reflecting the significant impact of stereochemistry on degradation kinetics.     

The Chemistry,Biology, and Modulation of Ammonium Nitrification in Soil

Approximately two percent of the world's energy is consumed in the production of ammonia from hydrogen and nitrogen gas. Ammonia is used as a fertilizer ingredient for agriculture and distributed in the environment on an enormous scale to promote crop growth in intensive farming. Only 30–50 % of the nitrogen applied is assimilated by crop plants; the remaining 50–70 % goes into biological processes such as nitrification by microbial metabolism in the soil. This leads to an imbalance in the global nitrogen cycle and higher nitrous oxide emissions (a potent and significant greenhouse gas) as well as contamination of ground and surface waters by nitrate from the nitrogen‐fertilized farmland. This Review gives a critical overview of the current knowledge of soil microbes involved in the chemistry of ammonia nitrification, the structures and mechanisms of the enzymes involved, and phytochemicals capable of inhibiting ammonia nitrification.     

Simultaneous analysis of tannin and lignin signatures in soils by thermally assisted hydrolysis and methylation using 13C-labeled TMAH

Tannin, condensed and hydrolysable, and lignin are two of the most abundant natural biopolymers in the environment. Yet it is still not possible using one analytical technique to simultaneously track each of their dynamics in litter and soils. Thermally assisted hydrolysis and methylation (THM) using tetramethylammonium hydroxide (TMAH) has been employed to investigate the cycling of tannin and lignin forms in one analysis, but sometimes with equivocal results as many of the products released may originate from both biopolymers. In this study we applied ¹³C-labeled TMAH in the analysis of soil organic matter in a soil profile under Corsican pine, an input lacking in hydrolysable tannins, to show the potential of this tool in tracking complex phenol chemistry. This method successfully allowed for a qualitative distinction among tannin and lignin input as well as permitting the inference of ring specific decay of condensed tannins.     

Organic soil as a radionuclide sink in a High Arctic environment

Summary The role of organic soil as a sink for radioactive contaminants in a High Arctic environment was studied. Samples were obtained from an area of organic soil located on the Arctic archipelago of Svalbard (79° N) and from a non-organic control site in the same region. Samples were differentiated into organic layers and the underlying material and measured for a suite of anthropogenic and natural radionuclides and for a variety of soil chemistry parameters. Results indicated that the organic components of the soil constitute a sink term for a number of radionuclides. Values for Pu isotopes, ¹³⁷Cs and ²³⁸U were appreciably higher at the study site than at the control site, by up to a factor of 40 for Pu and 20 for ¹³⁷Cs and ²³⁸U. The source of ²³⁸U to the site appeared to be enrichment of this isotope from surface or melt water via adsorption to to either iron hydroxides or organic matter although the situation pertaining to Pu and ¹³⁷Cs remains less clear.     

Decontamination of polluted urban soils by plants. Our possibilities to enhance the uptake of heavy metals

Pot experiments were carried out to assess the influence of two plantspecies on chemistry of polluted and unpolluted urban soils. Change in pHand acid neutralization capacity of the soils, as well as variations in elementalcomposition of soil leachates and in total concentrations of elements in thesoil were studied by INAA and ICP-AES. Concentrations of 28 elements in plantswere determined by INAA. Cultivation of plants led to significant change insoil parameters. In particular, acid neutralization capacity of polluted soilincreased, resulting in increase in element uptake.     

烟台地区氟中毒的环境因素分析

介绍氟中毒的症状以及发病机理。对烟台地区氟中毒的引发因素进行了综述。从土壤与母质、地形、地貌、岩性与矿物成分、水化学类型、地下水温度、气候及饮食状况等多个方面对烟台地区发生的氟中毒进行环境因素分析,分别阐述了各个因子的特征与该地区发病情况的关系。根据引发烟台地区氟中毒的环境因素提出防治氟中毒的对策。     

Eigen kinetics in surface complexation of aqueous metal ions

The mechanism of chemisorption of aqueous metal ions at surfaces has long been a topical issue in such fields as soil chemistry and bioenvironmental science. Here it is quantitatively demonstrated for the first time that release of water from the inner hydration shell is the rate-limiting step in inner-sphere surface complexation. The reactive intermediate is an outer-sphere complex between metal ion and surface site, with an electrostatically controlled stability defined by Boltzmann statistics. Using tabulated dehydration rate constants for metal ions, the resulting scheme allows for prediction of rates of sorption of aqueous metal ions at any type of complexing surface.