莠去津磁性分子印迹材料制备与吸附应用研究

以莠去津(atrazine)为模板分子,甲基丙烯酸(methyl acrylic acid,MAA)为功能单体,Fe3O4磁性纳米微球为载体,制备了具有特异性识别莠去津的磁性分子印迹聚合物。通过Langmuir等温吸附模型得莠去津分子印迹聚合物(atrazine-magnetic molecularly imprinted polymer,AT-MMIPs)最大吸附量为84.34mg/g;结合吸附动力学模型和吸附位点Scatchard方程对莠去津磁性分子印迹聚合物进行了吸附机理分析。对水库水样中存在的痕量莠去津进行了模拟检测分析,结果表明莠去津磁性分子印迹聚合物用于检测水样中残存的痕量莠去津是可行的。     

Model forecasts of atrazine in Lake Michigan in response to various sensitivity and potential management scenarios

For more than forty years, the herbicide atrazine has been used on corn crops in the Lake Michigan basin to control weeds. It is usually applied to farm fields in the spring before or after the corn crop emerges. A version of the WASP4 mass balance model, LM2-Atrazine, was used to assess the impact of the historical and future usage of this chemical on lake water concentrations. Long-term model forecasts were performed under various sensitivity and potential management scenarios. The model was calibrated to available lake data and results indicate that atrazine, under average conditions, is decaying very slowly in the lake (0.009/year). This kinetic decay translates into a half-life estimate of 77 years. If the average condition scenario were assumed to remain constant into the future and reflective of conditions in January 1, 2005, it is expected that the lake (excluding Green Bay) would eventually reach a volume-weighted average atrazine concentration of approximately 67 ng/L in the year 2157 (current model prediction is 48 ng/L for year 2011). These forecasted lake-wide concentrations are below known water quality criteria for the protection of aquatic ecosystems.     

A fugacity based continuous and dynamic fate and transport model for river networks and its application to Altamaha River

In this paper, a continuous and dynamic fugacity-based contaminant fate and transport model is developed. The dynamic interactions among all phases in the physical domain are addressed through the use of the fugacity approach instead of the use of concentration as the unknown variable. The full form of Saint Venant equations is used in order to solve for the hydrodynamic conditions in the river network. Then a fugacity-based advection-dispersion equation is modeled to examine the fate and transport of contaminants in the river network for all phases.The fugacity-based, dynamic and continuous contaminant fate and transport model developed here is applied to Altamaha River in Georgia, USA to demonstrate its use in environmental exposure analysis. Altamaha River is the largest river system east of Mississippi which offers habitat for many species, including about 100 rare endangered species, along its 140 mile course. Polychlorinated biphenyls (PCBs), a highly hydrophobic and toxic chemical ubiquitous in nature, and atrazine, the most commonly-used agricultural pesticide are modeled as contaminants in this demonstration. Through this approach the concentration distribution of PCBs and atrazine in the water column of Altamaha River as well as the sediments can be obtained with relative ease, which is an improvement over concentration based analysis of phase distribution of contaminants.     

Atrazine removal using adsorption and electrochemical regeneration

This paper demonstrates the removal of atrazine using a novel carbon-based adsorbent to below 1.0 microg l(-1) and its subsequent electrochemical regeneration in a simple electrochemical cell. Effective electrochemical regeneration can be achieved with a treatment time as low as 20 min over a number of adsorption/regeneration cycles using laboratory-prepared solutions. The results suggest that electrochemical modification of the particulate surface on electrochemical regeneration can result in adsorptive capacities three times greater than originally achieved.     

Application of a three-component competitive adsorption model to evaluate and optimize granular activated carbon systems

A recently developed kinetic model for granular activated carbon (GAC) adsorbers (COMPSORB-GAC) that quantitatively describes the adsorption of trace organic contaminant in the presence of competing natural organic matter (NOM) was applied to evaluate the performance of different GAC system configurations: conventional fixed-bed adsorbers, layered upflow carbon adsorbers (LUCA), and moving-bed adsorbers (with few or many bed sections). COMPSORB-GAC separately tracks the adsorption of three components: a trace compound, a strongly competing NOM fraction that reduces trace compound equilibrium capacity, and a pore-blocking NOM fraction that reduces kinetics. Performance was simulated for various design criteria and with model parameters derived for two natural waters with significantly different NOM concentrations. For the range of simulated conditions and with baseline performance defined by a fixed-bed adsorber, LUCA generally reduced carbon usage rates (CURs) by 15-35%. A 2-section and a 16-section moving-bed reactor reduced baseline CURs by 20-30% and 45-55%, respectively. Projected CURs for the water source with a relatively high NOM concentration were 2-3 times higher for all reactor configurations and indicated that NOM preloading would cause performance deterioration in deep GAC beds, which highlights the importance of source water quality. These results show how COMPSORB-GAC can be used in a comprehensive, site-specific optimization of GAC systems to ensure robust system performance and to balance capital and operating costs.     

Fabrication of flexible interdigitated μ-electrodes (FIDμEs) for the development of a conductimetric immunosensor for atrazine detection based on antibodies labelled with gold nanoparticles

The present paper describes a simple and low-cost method for the fabrication of mechanically flexible interdigitated μ-electrodes (FIDμEs) and its application as immunosensor.FIDμEs consist of two coplanar non-passivated interdigitated metallic μ-electrodes supported on a flexible transparent substrate, polyethylene naphthalate (PEN). Bioreagents deposition on PEN substrates becomes possible by depositing SiO₂ on the electrodes surface (fingers and inter-digits space).These FIDμEs were successfully applied for the development of a selective conductimetric immunosensor for the quantification of atrazine residues. The immunosensor has been demonstrated for detection of small amounts of atrazine, thanks to the use of immunoreagents specifically developed to detect this pesticide.The detection method applied is based on the use of antibodies labelled with gold nanoparticles. The presence of these particles amplifies the conductive signal; hence the immunosensor response was quantified using simple and inexpensive DC measurements.Immunochemical detection of the concentrations of atrazine is achieved by a competitive reaction which occurs before the inclusion of the labelled antibodies.The immunosensor shows limits of detection in the order of 2-3 μg L⁻¹, far below the maximum residue level (50 μg kg⁻¹) established by EU for residues of atrazine as herbicide in the wine grapes and other foodstuff products.     

Compromise Between Bromate Ion Formation and Pesticides Degradation and/or Manganese Removal

Ozonation is a widely used technology within the water industry. Bromate ion formed by oxidation of water containing bromide ion was studied with the Gas Ozone Test and Pilot Scale Ozonation. Bromate ion formation was investigated along with the removal of triazines and/or manganese. Under identical conditions of ozonation, BrO₃ ^? formation is specific for each water and depends on parameters such as Total Organic Carbon, UV absorbance at 254 nm, applied ozone and ozone residual. Pesticides degradation by ozonation alone cannot be achieved without the formation of BrO₃ ^? at a high concentration. Hydrogen peroxide, at a constant ozone dose, reduces the BrO₃ ^? formation. However, even with the use of hydrogen peroxide, the concentration of BrO₃ ^? can remain in excess of the provisional Maximum Contaminant Level (10 μg/L). For certain types of water, pesticide degradation is difficult to achieve if the MCL for BrO₃ ^? has to be met. Manganese oxidation by ozone appears to be achieved without high bromate formation; indeed the presence of manganese hinders BrO₃ ^? formation.     

Theoretical Aspects Of The Kinetics Of Competitive Ozone Reactions In Water

Competition of direct and decomposition reactions that ozone can undergo in water when a given compound is present is studied according to concepts of absorption theories. The importance of different parameters, such as pH, rate constants, mass transfer coefficients and concentration of reactants, is considered to clarify which reaction prevails. Parameters like Hatta numbers (film theory) or diffusion and reaction times (surface renewal theories) are key factors to check the competition of these reactions.     

生物测定法和重量法用于分析阿特拉津除草膜药效的评价

本文介绍了生物测定法和重法用于分析阿特拉津除昌地膜药效的研究结果。浮萍生测法对阿特拉津浓度的分辨力较低，只可作为除草膜药效定性分析的方法，柯氏藻生测法灵敏度高，对除草膜含药量差异的分辨力较高试验周期较短，是除草膜药效分析的较好方法；田间除草效果试验一般来验证其它方法的可靠性，其试验周期长，只能用于评价少量样本的除草效果；重不操作简便，可作为分析工艺条件对除划剂在膜面的分布关况影响的简便方法。     

Ozonation of Aqueous Solutions of Nitrogen Heterocyclic Compounds : Benzotriazoles,Atrazine and Amitrole

Study of the ozonation of aqueous solutions of four heterocyclic nitrogen compounds, at slightly acidic pH in a heterogeneous gas-liquid system, showed that the reactivities of these compounds are different. Amitrole, a five-membered ring heterocycle, has been found to be a highly reactive compound, while atrazine, a six-membered ring heterocycle, has been found to be a poorly reactive compound. The benzotriazoles, benz-fused five-membered ring heterocycles, present intermediate reactivities. Moreovoer, the chemical natures of the ozonation by-products have been found to be different between amitrole and atrazine. With atrazine, ozone did not open the heterocyclic ring, and led to the formation of a trioxotriazine. With amitrole, ozone broke the heterocyclic ring and formed mainly formamide.